dropbear: tomsfastmath/tfm.tex annotate

annotate tomsfastmath/tfm.tex @ 646:f10335e5e42f dropbear-tfm

- More asm constraint fixes. Now seems to build OK on 32-bit OS X.

author	Matt Johnston <matt@ucc.asn.au>
date	Wed, 30 Nov 2011 23:03:47 +0800
parents	a362b62d38b2
children

rev	line source
643 a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	1 \documentclass[b5paper]{book}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	2 \usepackage{hyperref}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	3 \usepackage{makeidx}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	4 \usepackage{amssymb}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	5 \usepackage{color}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	6 \usepackage{alltt}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	7 \usepackage{graphicx}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	8 \usepackage{layout}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	9 \def\union{\cup}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	10 \def\intersect{\cap}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	11 \def\getsrandom{\stackrel{\rm R}{\gets}}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	12 \def\cross{\times}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	13 \def\cat{\hspace{0.5em} \\| \hspace{0.5em}}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	14 \def\catn{$\\|$}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	15 \def\divides{\hspace{0.3em} \| \hspace{0.3em}}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	16 \def\nequiv{\not\equiv}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	17 \def\approx{\raisebox{0.2ex}{\mbox{\small $\sim$}}}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	18 \def\lcm{{\rm lcm}}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	19 \def\gcd{{\rm gcd}}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	20 \def\log{{\rm log}}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	21 \def\ord{{\rm ord}}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	22 \def\abs{{\mathit abs}}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	23 \def\rep{{\mathit rep}}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	24 \def\mod{{\mathit\ mod\ }}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	25 \renewcommand{\pmod}[1]{\ ({\rm mod\ }{#1})}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	26 \newcommand{\floor}[1]{\left\lfloor{#1}\right\rfloor}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	27 \newcommand{\ceil}[1]{\left\lceil{#1}\right\rceil}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	28 \def\Or{{\rm\ or\ }}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	29 \def\And{{\rm\ and\ }}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	30 \def\iff{\hspace{1em}\Longleftrightarrow\hspace{1em}}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	31 \def\implies{\Rightarrow}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	32 \def\undefined{{\rm ``undefined"}}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	33 \def\Proof{\vspace{1ex}\noindent {\bf Proof:}\hspace{1em}}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	34 \let\oldphi\phi
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	35 \def\phi{\varphi}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	36 \def\Pr{{\rm Pr}}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	37 \newcommand{\str}[1]{{\mathbf{#1}}}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	38 \def\F{{\mathbb F}}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	39 \def\N{{\mathbb N}}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	40 \def\Z{{\mathbb Z}}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	41 \def\R{{\mathbb R}}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	42 \def\C{{\mathbb C}}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	43 \def\Q{{\mathbb Q}}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	44 \definecolor{DGray}{gray}{0.5}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	45 \newcommand{\emailaddr}[1]{\mbox{$<${#1}$>$}}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	46 \def\twiddle{\raisebox{0.3ex}{\mbox{\tiny $\sim$}}}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	47 \def\gap{\vspace{0.5ex}}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	48 \makeindex
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	49 \begin{document}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	50 \frontmatter
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	51 \pagestyle{empty}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	52 \title{TomsFastMath User Manual \\ v0.12}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	53 \author{Tom St Denis \\ [email protected]}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	54 \maketitle
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	55 This text and library are all hereby placed in the public domain. This book has been formatted for B5
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	56 [176x250] paper using the \LaTeX{} {\em book} macro package.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	57
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	58 \vspace{13cm}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	59
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	60 \begin{flushleft}This project was sponsored in part by
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	61
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	62 Secure Science Corporation \url{http://www.securescience.net}.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	63 \end{flushleft}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	64
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	65 \tableofcontents
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	66 \listoffigures
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	67 \mainmatter
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	68 \pagestyle{headings}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	69 \chapter{Introduction}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	70 \section{What is TomsFastMath?}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	71
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	72 TomsFastMath is meant to be a very fast yet still fairly portable and easy to port large
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	73 integer arithmetic library written in ISO C. The goal specifically is to be able to perform
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	74 very fast modular exponentiations and other related functions required for ECC, DH and RSA
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	75 cryptosystems.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	76
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	77 Most of the library is pure ISO C portable source code while a small portion (three files) contain
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	78 a mixture of ISO C and assembler inline fragments. Compared to LibTomMath this new library is
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	79 meant to be much faster while sacrificing flexibiltiy. This is accomplished through several means.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	80
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	81 \begin{enumerate}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	82 \item The new code is slightly messier and contains asm blocks.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	83 \item This uses fixed not multiple precision integers.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	84 \item It is designed only for fast modular exponentiations [e.g. less flexibility].
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	85 \end{enumerate}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	86
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	87 To mitigate some of the problems that arise from using assembler it has been carefully and
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	88 appropriately used where it would make the most gain in performance. Also we use macro's
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	89 for assembler code which allows new ports to be inserted easily.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	90
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	91 The new code uses fixed precision arithmetic which means at compile time you choose a maximum
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	92 precision and all numbers are limited to that. This has the benefit of not requiring any
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	93 memory heap operations (which are slow) in any of the functions. It has the downside that
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	94 integers that are too large are truncated.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	95
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	96 The goal of this library is to be able to perform modular exponentiations (with an odd modulus) very
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	97 fast. This is what takes the most time in systems such as RSA and DH. This also requires
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	98 fast multiplication and squaring and has the side effect of speeding up ECC operations as well.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	99
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	100 \section{License}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	101 TomsFastMath is public domain.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	102
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	103 \section{Building}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	104 To build the library simply type ``make''. Or to install in typical *unix like directories use
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	105 ``make install''. Similarly a shared library can be built with ``make -f makefile.shared install''.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	106
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	107 You can build the test program with ``make test''. To perform simple static testing (useful to
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	108 test out new assembly ports) use the stest program. Type ``make stest'' and run it on your
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	109 target. The program will perform three multiplications, squarings and montgomery reductions.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	110 Likely if your assembly code is invalid this code will exhibit the bug.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	111
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	112 \subsection{Intel CC}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	113 In theory you should be able to build the library with
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	114
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	115 \begin{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	116 CFLAGS="-O3 -ip" CC=icc make IGNORE_SPEED=1
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	117 \end{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	118
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	119 However, Intels inline assembler is way less advanced than GCCs. As a result it doesn't compile.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	120 Fortunately it doesn't really matter.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	121
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	122 \subsection{MSVC}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	123 The library doesn't build with MSVC. Imagine that.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	124
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	125 \subsection{Build Limitations}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	126 TomsFastMath has the following build requirements which are non--portable but under most
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	127 circumstances not problematic.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	128
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	129 \begin{enumerate}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	130 \item ``CHAR\_BIT'' must be eight.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	131 \item The ``fp\_digit'' type must be a multiple of eight bits long.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	132 \item The ``fp\_word'' must be at least twice the length of fp\_digit.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	133 \end{enumerate}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	134
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	135 \subsection{Optimization Configuration}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	136 By default TFM is configured for 32--bit digits using ISO C source code. This mode while portable
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	137 is not very efficient. While building the library (from scratch) you can define one of
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	138 several ``CFLAGS'' defines.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	139
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	140 For example, to build with with SSE2 optimizations type
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	141
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	142 \begin{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	143 CFLAGS=-DTFM_SSE2 make clean libtfm.a
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	144 \end{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	145
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	146 \subsubsection{x86--32} The ``x86--32'' mode is defined by ``TFM\_X86'' and covers all
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	147 i386 and beyond processors. It requires GCC to build and only works with 32--bit digits. In this
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	148 mode fp\_digit is 32--bits and fp\_word is 64--bits. This mode will be autodetected when building
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	149 with GCC to an ``i386'' target. You can override this behaviour by defining TFM\_NO\_ASM or
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	150 another optimization mode (such as SSE2).
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	151
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	152 \subsubsection{SSE2} The ``SSE2'' mode is defined by ``TFM\_SSE2'' and requires a Pentium 4, Pentium
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	153 M or Athlon64 processor. It requires GCC to build. Note that you shouldn't define both
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	154 TFM\_X86 and TFM\_SSE2 at the same time. This mode only works with 32--bit digits. In this
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	155 mode fp\_digit is 32--bits and fp\_word is 64--bits. While this mode will work on the AMD Athlon64
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	156 series of processors it is less efficient than the native ``x86--64'' mode and not recommended.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	157
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	158 There is an additional ``TFM\_PRESCOTT'' flag that you can define for P4 Prescott processors. This causes
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	159 the mul/sqr functions to use x86\_32 and the montgomery reduction to use SSE2 which is (so far) the fastest
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	160 combination. If you are using an older (e.g. Northwood) generation P4 don't define this.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	161
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	162 \subsubsection{x86--64} The ``x86--64'' mode is defined by ``TFM\_X86\_64'' and requires a
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	163 ``x86--64'' capable processor (Athlon64 and future Pentium processors). It requires GCC to
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	164 build and only works with 64--bit digits. Note that by enabling this mode it will automatically
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	165 enable 64--bit digits. In this mode fp\_digit is 64--bits and fp\_word is 128--bits. This mode will
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	166 be autodetected when building with GCC to an ``x86--64'' target. You can override this behaviour by defining
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	167 TFM\_NO\_ASM.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	168
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	169 \subsubsection{ARM} The ``ARM'' mode is defined by ``TFM\_ARM'' and requires a ARMv4 with the M instructions (enhanced
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	170 multipliers) or higher processor. It requires GCC and works with 32--bit digits. In this mode fp\_digit is 32--bits and
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	171 fp\_word is 64--bits.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	172
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	173 \subsubsection{PPC32} The ``PPC32'' mode is defined by ``TFM\_PPC32'' and requires a standard PPC processor. It doesn't
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	174 use altivec or other extensions so it should work on all compliant implementations of PPC. It requires GCC and works
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	175 with 32--bit digits. In this mode fp\_digit is 32--bits and fp\_word is 64--bits.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	176
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	177 \subsubsection{PPC64} The ``PPC64'' mode is defined by ``TFM\_PPC64'' and requires a 64--bit PPC processor.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	178
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	179 \subsubsection{AVR32} The ``AVR32'' mode is defined by ``TFM\_AVR32'' and requires an Atmel AVR32 processor.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	180
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	181 \subsubsection{Future Releases} Future releases will support additional platform optimizations.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	182 Developers of MIPS and SPARC platforms are encouraged to submit GCC asm inline patches
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	183 (see chapter \ref{chap:asmops} for more information).
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	184
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	185 \begin{figure}[here]
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	186 \begin{small}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	187 \begin{center}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	188 \begin{tabular}{\|l\|l\|}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	189 \hline \textbf{Processor} & \textbf{Recommended Mode} \\
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	190 \hline All 32--bit x86 platforms & TFM\_X86 \\
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	191 \hline Pentium 4 & TFM\_SSE2 \\
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	192 \hline Pentium 4 Prescott & TFM\_SSE2 + TFM\_PRESCOTT \\
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	193 \hline Athlon64 & TFM\_X86\_64 \\
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	194 \hline ARMv4 or higher with M & TFM\_ARM \\
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	195 \hline G3/G4 (32-bit PPC) & TFM\_PPC32 \\
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	196 \hline G5 (64-bit PPC) & TFM\_PPC64 \\
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	197 \hline Atmel AVR32 & TFM\_AVR32 \\
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	198 \hline &\\
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	199 \hline x86--32 or x86--64 (with GCC) & Leave blank and let autodetect work \\
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	200 \hline
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	201 \end{tabular}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	202 \caption{Recommended Build Modes}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	203 \end{center}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	204 \end{small}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	205 \end{figure}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	206
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	207 \subsection{Build Configurations}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	208 TomsFastMath is configurable in terms of which unrolled code (if any) is included. By default, the majority of the code is included which
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	209 results in large binaries. The first flag to try out is TFM\_ALREADY\_SET which tells TFM to turn off \textbf{all} unrolled code. This will
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	210 result in a smaller library but also a much slower library.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	211
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	212 From this clean state, you can start enabling unrolled code for given cryptographic tasks at hand. A series of TFM\_MULXYZ and TFM\_SQRXYZ macros
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	213 exist to enable specific unrolled code. For instance, TFM\_MUL32 will enable a 32 digit unrolled multiplier. For a complete list see the tfm.h header
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	214 file. Keep in mind this is for digits not bits. For example, you should enable TFM\_MUL16 if you are doing 1024-bit exptmods on a 64--bit platform, enable
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	215 TFM\_MUL32 on 32--bit platforms.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	216
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	217 To help developers use ECC there are a set of defines for the five NIST curve sizes. They are named TFM\_ECCXYZ where XYZ is one of 192, 224, 256, 384, or 521. These
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	218 enable the multipliers and squaring code for a given curve, autodetecting 64--bit platforms as well.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	219
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	220 \subsection{Precision Configuration}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	221 The precision of all integers in this library are fixed to a limited precision. Essentially
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	222 the rule of setting the precision is if you plan on doing modular exponentiation with $k$--bit
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	223 numbers than the precision must be fixed to $2k$--bits plus four digits.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	224
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	225 This is changed by altering the value of ``FP\_MAX\_SIZE'' in tfm.h to your desired size. By default,
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	226 the library is configured to handle upto 2048--bit inputs to the modular exponentiator.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	227
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	228 \chapter{Getting Started}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	229 \section{Data Types}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	230 TomsFastMath is a large fixed precision integer library. It provides the functionality to
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	231 manipulate large signed integers through a relatively trivial api and a single data type.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	232
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	233 The ``fp\_int'' or fixed precision integer is the data type that the functions operate with.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	234
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	235 \begin{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	236 typedef struct {
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	237 fp_digit dp[FP_SIZE];
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	238 int used,
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	239 sign;
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	240 } fp_int;
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	241 \end{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	242
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	243 The \textbf{dp} member is the array of digits that forms the number. It must always be zero
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	244 padded. The \textbf{used} member is the count of digits used in the array. Although the
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	245 precision is fixed the algorithms are still tuned to not process the entire array if it
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	246 does not have to. The \textbf{sign} indicates the sign of the integer. It is \textbf{FP\_ZPOS} (0)
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	247 if the integer is zero or positive and \textbf{FP\_NEG} (1) otherwise.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	248
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	249 \section{Initialization}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	250 \subsection{Simple Initialization}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	251 To initialize an integer to the default state of zero use the fp\_init() function.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	252
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	253 \index{fp\_init}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	254 \begin{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	255 void fp_init(fp_int *a);
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	256 \end{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	257
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	258 This will initialize the fp\_int $a$ to zero. Note that the function fp\_zero() is an alias
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	259 for fp\_init().
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	260
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	261 \subsection{Initialize Small Constants}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	262 To initialize an integer with a small single digit value use the fp\_set() function.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	263
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	264 \index{fp\_set}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	265 \begin{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	266 void fp_set(fp_int *a, fp_digit b);
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	267 \end{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	268
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	269 This will initialize $a$ and set it equal to the digit $b$.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	270
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	271 \subsection{Initialize Copy}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	272 To initialize an integer with a copy of another integer use the fp\_init\_copy() function.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	273
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	274 \index{fp\_init\_copy}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	275 \begin{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	276 void fp_init_copy(fp_int a, fp_int b)
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	277 \end{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	278
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	279 This will initialize $a$ as a copy of $b$. Note that for compatibility with LibTomMath the function
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	280 fp\_copy() is also provided.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	281
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	282 \chapter{Arithmetic Operations}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	283 \section{Odds and Evens}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	284 To quickly and easily tell if an integer is zero, odd or even use the following functions.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	285
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	286 \index{fp\_iszero} \index{fp\_iseven} \index{fp\_isodd}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	287 \begin{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	288 int fp_iszero(fp_int *a);
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	289 int fp_iseven(fp_int *a);
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	290 int fp_isodd(fp_int *a);
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	291 \end{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	292
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	293 These will return \textbf{FP\_YES} if the answer to their respective questions is yes. Otherwise they
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	294 return \textbf{FP\_NO}. Note that these are implemented as macros and as such you should avoid using
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	295 ++ or --~-- operators on the input operand.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	296
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	297 \section{Sign Manipulation}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	298 To negate or compute the absolute of an integer use the following functions.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	299
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	300 \index{fp\_neg} \index{fp\_abs}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	301 \begin{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	302 void fp_neg(fp_int a, fp_int b);
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	303 void fp_abs(fp_int a, fp_int b);
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	304 \end{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	305 This will compute the negation (or absolute) of $a$ and store the result in $b$. Note that these
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	306 are implemented as macros and as such you should avoid using ++ or --~-- operators on the input
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	307 operand.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	308
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	309 \section{Comparisons}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	310 To perform signed or unsigned comparisons use following functions.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	311
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	312 \index{fp\_cmp} \index{fp\_cmp\_mag}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	313 \begin{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	314 int fp_cmp(fp_int a, fp_int b);
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	315 int fp_cmp_mag(fp_int a, fp_int b);
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	316 \end{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	317 These will compare $a$ to $b$. They will return \textbf{FP\_GT} if $a$ is larger than $b$,
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	318 \textbf{FP\_EQ} if they are equal and \textbf{FP\_LT} if $a$ is less than $b$.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	319
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	320 The function fp\_cmp performs signed comparisons while the other performs unsigned comparisons.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	321
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	322 \section{Shifting}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	323 To shift the digits of an fp\_int left or right use the following functions.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	324
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	325 \index{fp\_lshd} \index{fp\_rshd}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	326 \begin{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	327 void fp_lshd(fp_int *a, int x);
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	328 void fp_rshd(fp_int *a, int x);
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	329 \end{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	330
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	331 These will shift the digits of $a$ left (or right respectively) $x$ digits.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	332
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	333 To shift individual bits of an fp\_int use the following functions.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	334
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	335 \index{fp\_div\_2d} \index{fp\_mod\_2d} \index{fp\_mul\_2d} \index{fp\_div\_2} \index{fp\_mul\_2}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	336 \begin{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	337 void fp_div_2d(fp_int a, int b, fp_int c, fp_int *d);
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	338 void fp_mod_2d(fp_int a, int b, fp_int c);
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	339 void fp_mul_2d(fp_int a, int b, fp_int c);
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	340 void fp_mul_2(fp_int a, fp_int c);
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	341 void fp_div_2(fp_int a, fp_int c);
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	342 void fp_2expt(fp_int *a, int b);
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	343 \end{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	344 fp\_div\_2d() will divide $a$ by $2^b$ and store the quotient in $c$ and remainder in $d$. Either of
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	345 $c$ or $d$ can be \textbf{NULL} if their value is not required. fp\_mod\_2d() is a shortcut to
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	346 compute the remainder directly. fp\_mul\_2d() will multiply $a$ by $2^b$ and store the result in $c$.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	347
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	348 The fp\_mul\_2() and fp\_div\_2() functions are optimized multiplication and divisions by two. The
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	349 function fp\_2expt() will compute $a = 2^b$ quickly.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	350
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	351 To quickly count the number of least significant bits that are zero use the following function.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	352
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	353 \index{fp\_cnt\_lsb}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	354 \begin{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	355 int fp_cnt_lsb(fp_int *a);
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	356 \end{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	357 This will return the number of adjacent least significant bits that are zero. This is equivalent
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	358 to the number of times two evenly divides $a$.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	359
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	360 \section{Basic Algebra}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	361
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	362 The following functions round out the basic algebraic functionality of the library.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	363
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	364 \index{fp\_add} \index{fp\_sub} \index{fp\_mul} \index{fp\_sqr} \index{fp\_div} \index{fp\_mod}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	365 \begin{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	366 void fp_add(fp_int a, fp_int b, fp_int *c);
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	367 void fp_sub(fp_int a, fp_int b, fp_int *c);
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	368 void fp_mul(fp_int a, fp_int b, fp_int *c);
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	369 void fp_sqr(fp_int a, fp_int b);
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	370 int fp_div(fp_int a, fp_int b, fp_int c, fp_int d);
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	371 int fp_mod(fp_int a, fp_int b, fp_int *c);
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	372 \end{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	373
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	374 The functions fp\_add(), fp\_sub() and fp\_mul() perform their respective operations on $a$ and
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	375 $b$ and store the result in $c$. The function fp\_sqr() computes $b = a^2$ and is faster than
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	376 using fp\_mul() to perform the same operation.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	377
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	378 The function fp\_div() divides $a$ by $b$ and stores the quotient in $c$ and remainder in $d$. Either
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	379 of $c$ and $d$ can be \textbf{NULL} if the result is not required. The function fp\_mod() is a simple
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	380 shortcut to find the remainder.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	381
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	382 \section{Modular Exponentiation}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	383 To compute a modular exponentiation use the following function.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	384
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	385 \index{fp\_exptmod}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	386 \begin{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	387 int fp_exptmod(fp_int a, fp_int b, fp_int c, fp_int d);
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	388 \end{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	389 This computes $d \equiv a^b \mbox{ (mod }c\mbox{)}$ for any odd $c$ and $b$. $b$ may be negative so long as
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	390 $a^{-1} \mbox{ (mod }c\mbox{)}$ exists. The initial value of $a$ may be larger than $c$. The size of $c$ must be
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	391 half of the maximum precision used during the build of the library. For example, by default $c$ must be less
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	392 than $2^{2048}$.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	393
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	394 \section{Number Theoretic}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	395
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	396 To perform modular inverses, greatest common divisor or least common multiples use the following
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	397 functions.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	398
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	399 \index{fp\_invmod} \index{fp\_gcd} \index{fp\_lcm}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	400 \begin{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	401 int fp_invmod(fp_int a, fp_int b, fp_int *c);
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	402 void fp_gcd(fp_int a, fp_int b, fp_int *c);
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	403 void fp_lcm(fp_int a, fp_int b, fp_int *c);
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	404 \end{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	405
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	406 The fp\_invmod() function will find the modular inverse of $a$ modulo an odd modulus $b$ and store
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	407 it in $c$ (provided it exists). The function fp\_gcd() will compute the greatest common
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	408 divisor of $a$ and $b$ and store it in $c$. Similarly the fp\_lcm() function will compute
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	409 the least common multiple of $a$ and $b$ and store it in $c$.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	410
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	411 \section{Prime Numbers}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	412 To quickly test a number for primality call this function.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	413
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	414 \index{fp\_isprime}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	415 \begin{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	416 int fp_isprime(fp_int *a);
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	417 \end{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	418 This will return \textbf{FP\_YES} if $a$ is probably prime. It uses 256 trial divisions and
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	419 eight rounds of Rabin-Miller testing. Note that this routine performs modular exponentiations
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	420 which means that $a$ must be in a valid range of precision.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	421
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	422 \chapter{Porting TomsFastMath}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	423 \label{chap:asmops}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	424 \section{Getting Started}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	425 Porting TomsFastMath to a given processor target is usually a simple procedure. For the most part
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	426 assembly is used to get around the lack of a ``add with carry'' operation in the C language. To
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	427 make matters simpler the use of assembler is through macro blocks.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	428
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	429 Each ``port'' is defined by a block of code that re-defines the portable ISO C macros with assembler
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	430 inline blocks. To add a new port you must designate a TFM\_XXX define that will enable your
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	431 port when built.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	432
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	433 \section{Multiply with Comba}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	434 The file ``fp\_mul\_comba.c'' is responsible for providing the fast multiplication within the
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	435 library. This comba multiplication is fairly simple. It uses a sliding three digit carry
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	436 system with the variables $c0$, $c1$, $c2$. For every digit of output $c0$ is the what will
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	437 be that digit, $c1$ will carry into the next digit and $c2$ will be the ``c1'' carry for
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	438 the next digit. For every ``next'' digit effectively $c0$ is stored as output, $c1$ moves into
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	439 $c0$, $c2$ into $c1$ and zero into $c2$.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	440
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	441 The following macros define the assmebler interface to the code.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	442
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	443 \begin{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	444 #define COMBA_START
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	445 \end{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	446
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	447 This is issued at the beginning of the multiplication function. This is in place to allow you to
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	448 initialize any registers or machine words required. You can leave it blank if you do not need
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	449 it.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	450
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	451 \begin{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	452 #define COMBA_CLEAR \
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	453 c0 = c1 = c2 = 0;
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	454 \end{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	455
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	456 This clears the three comba carries. If you are going to place carries in registers then
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	457 zero the appropriate registers. Note that the functions do not use $c0$, $c1$ or $c2$ directly
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	458 so you are free to ignore these varibles and use registers directly.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	459
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	460 \begin{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	461 #define COMBA_FORWARD \
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	462 c0 = c1; c1 = c2; c2 = 0;
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	463 \end{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	464
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	465 This propagates the carries after a digit has been produced.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	466
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	467 \begin{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	468 #define COMBA_STORE(x) \
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	469 x = c0;
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	470 \end{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	471
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	472 This stores the $c0$ digit in the memory location specified by $x$. Note that if you manually
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	473 aliased $c0$ with a register than just store that register in $x$.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	474
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	475 \begin{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	476 #define COMBA_STORE2(x) \
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	477 x = c1;
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	478 \end{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	479
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	480 This stores the $c1$ digit in the memory location specified by $x$. Note that if you manually
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	481 aliased $c1$ with a register than just store that register in $x$.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	482
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	483 \begin{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	484 #define COMBA_FINI
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	485 \end{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	486
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	487 If at the end of the function you need to perform some action fill this macro in.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	488
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	489 \begin{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	490 #define MULADD(i, j) \
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	491 t = ((fp_word)i) * ((fp_word)j); \
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	492 c0 = (c0 + t); if (c0 < ((fp_digit)t)) ++c1; \
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	493 c1 = (c1 + (t>>DIGIT_BIT)); if (c1 < (t>>DIGIT_BIT)) ++c2;
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	494 \end{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	495
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	496 This macro performs the ``multiply and add'' step that is central to the comba
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	497 multiplier. It multiplies the fp\_digits $i$ and $j$ to produce a fp\_word result. Effectively
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	498 the double--digit value is added to the three-digit carry formed by $c0$, $c1$, $c2$ where $c0$
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	499 is the least significant digit.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	500
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	501 \section{Squaring with Comba}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	502 Squaring is similar to multiplication except that it uses a special ``multiply and add twice'' macro
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	503 that replaces multiplications that are not required.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	504
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	505 \begin{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	506 #define COMBA_START
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	507 \end{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	508
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	509 This allows for any initialization code you might have.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	510
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	511 \begin{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	512 #define CLEAR_CARRY \
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	513 c0 = c1 = c2 = 0;
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	514 \end{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	515
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	516 This will clear the carries. Like multiplication you can safely alias the three carry variables
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	517 to registers if you can/want to.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	518
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	519 \begin{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	520 #define COMBA_STORE(x) \
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	521 x = c0;
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	522 \end{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	523
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	524 Store the $c0$ carry to a given memory location.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	525
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	526 \begin{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	527 #define COMBA_STORE2(x) \
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	528 x = c1;
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	529 \end{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	530
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	531 Store the $c1$ carry to a given memory location.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	532
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	533 \begin{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	534 #define CARRY_FORWARD \
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	535 c0 = c1; c1 = c2; c2 = 0;
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	536 \end{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	537
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	538 Forward propagate all three carry variables.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	539
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	540 \begin{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	541 #define COMBA_FINI
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	542 \end{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	543
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	544 If you need to clean up at the end of the function.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	545
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	546 \begin{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	547 /* multiplies point i and j, updates carry "c1" and digit c2 */
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	548 #define SQRADD(i, j) \
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	549 t = ((fp_word)i) * ((fp_word)j); \
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	550 c0 = (c0 + t); if (c0 < ((fp_digit)t)) ++c1; \
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	551 c1 = (c1 + (t>>DIGIT_BIT)); if (c1 < (t>>DIGIT_BIT)) ++c2;
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	552 \end{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	553
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	554 This is essentially the MULADD macro from the multiplication code.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	555
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	556 \begin{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	557 /* for squaring some of the terms are doubled... */
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	558 #define SQRADD2(i, j) \
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	559 t = ((fp_word)i) * ((fp_word)j); \
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	560 c0 = (c0 + t); if (c0 < ((fp_digit)t)) ++c1; \
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	561 c1 = (c1 + (t>>DIGIT_BIT)); if (c1 < (t>>DIGIT_BIT)) ++c2; \
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	562 c0 = (c0 + t); if (c0 < ((fp_digit)t)) ++c1; \
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	563 c1 = (c1 + (t>>DIGIT_BIT)); if (c1 < (t>>DIGIT_BIT)) ++c2;
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	564 \end{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	565
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	566 This is like SQRADD except it adds the produce twice. It's similar to
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	567 computing SQRADD(i, j*2).
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	568
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	569 To further make things interesting the squaring code also has ``doubles'' (see my LTM book chapter five...) which are
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	570 handled with these macros.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	571
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	572 \begin{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	573 #define SQRADDSC(i, j) \
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	574 do { fp_word t; \
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	575 t = ((fp_word)i) * ((fp_word)j); \
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	576 sc0 = (fp_digit)t; sc1 = (t >> DIGIT_BIT); sc2 = 0; \
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	577 } while (0);
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	578 \end{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	579 This computes a product and stores it in the ``secondary'' carry registers $\left < sc0, sc1, sc2 \right >$.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	580
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	581 \begin{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	582 #define SQRADDAC(i, j) \
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	583 do { fp_word t; \
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	584 t = sc0 + ((fp_word)i) * ((fp_word)j); sc0 = t; \
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	585 t = sc1 + (t >> DIGIT_BIT); sc1 = t; sc2 += t >> DIGIT_BIT; \
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	586 } while (0);
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	587 \end{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	588 This computes a product and adds it to the ``secondary'' carry registers.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	589
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	590 \begin{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	591 #define SQRADDDB \
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	592 do { fp_word t; \
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	593 t = ((fp_word)sc0) + ((fp_word)sc0) + c0; c0 = t; \
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	594 t = ((fp_word)sc1) + ((fp_word)sc1) + c1 + (t >> DIGIT_BIT); c1 = t; \
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	595 c2 = c2 + ((fp_word)sc2) + ((fp_word)sc2) + (t >> DIGIT_BIT); \
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	596 } while (0);
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	597 \end{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	598 This doubles the ``secondary'' carry registers and adds the sum to the main carry registers. Really complicated.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	599
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	600 \section{Montgomery with Comba}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	601 Montgomery reduction is used in modular exponentiation and is most called function during
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	602 that operation. It's important to make sure this routine is very fast or all is lost.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	603
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	604 Unlike the two other comba routines this one does not use a single three--digit carry
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	605 system. It does have three--digit carries except that the routine steps through them
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	606 in the inner loop. This means you cannot alias them to registers (at all).
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	607
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	608 To make matters simple though the three arrays of carries are stored in one array. The
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	609 ``c0'' array resides in $c[0 \ldots OFF1-1]$, ``c1'' in $c[OFF1 \ldots OFF2-1]$ and ``c2'' in
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	610 $c[OFF2 \ldots OFF2+FP\_SIZE-1]$.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	611
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	612 \begin{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	613 #define MONT_START
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	614 \end{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	615
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	616 This allows you to insert anything at the start that you need.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	617
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	618 \begin{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	619 #define MONT_FINI
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	620 \end{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	621
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	622 This allows you to insert anything at the end that you need.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	623
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	624 \begin{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	625 #define LOOP_START \
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	626 mu = c[x] * mp;
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	627 \end{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	628
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	629 This computes the $\mu$ value for the inner loop. You can safely alias $mu$ and $mp$ to
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	630 a register if you want.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	631
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	632 \begin{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	633 #define INNERMUL \
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	634 do { fp_word t; \
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	635 _c[0] = t = ((fp_word)_c[0] + (fp_word)cy) + \
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	636 (((fp_word)mu) * ((fp_word)*tmpm++)); \
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	637 cy = (t >> DIGIT_BIT); \
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	638 } while (0)
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	639 \end{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	640
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	641 This computes the inner product and adds it to the destination and carry variable $cy$.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	642 This uses the $mu$ value computed above (can be in a register already) and the
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	643 $cy$ which is a chaining carry. Inside the INNERMUL loop the $cy$ value can be kept
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	644 inside a register (hint: it always starts as $cy = 0$ in the first iteration).
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	645
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	646 Upon completion of the inner loop the macro LOOP\_END is called which is used to fetch
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	647 $cy$ into the variable the C program can see. This is where, if you cached $cy$ in a
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	648 register you would copy it to the locally accessible C variable.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	649
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	650 \begin{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	651 #define PROPCARRY \
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	652 do { fp_digit t = _c[0] += cy; cy = (t < cy); } while (0)
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	653 \end{verbatim}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	654
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	655 This propagates the carry upwards by one digit.
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	656
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	657 \input{tfm.ind}
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	658
a362b62d38b2 Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a Matt Johnston <matt@ucc.asn.au> parents: diff changeset	659 \end{document}

Mercurial > dropbear

annotate tomsfastmath/tfm.tex @ 646:f10335e5e42f dropbear-tfm