Mercurial > dropbear
diff tomsfastmath/src/addsub/s_fp_add.c @ 643:a362b62d38b2 dropbear-tfm
Add tomsfastmath from git rev bfa4582842bc3bab42e4be4aed5703437049502a
with Makefile.in renamed
author | Matt Johnston <matt@ucc.asn.au> |
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date | Wed, 23 Nov 2011 18:10:20 +0700 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/tomsfastmath/src/addsub/s_fp_add.c Wed Nov 23 18:10:20 2011 +0700 @@ -0,0 +1,42 @@ +/* TomsFastMath, a fast ISO C bignum library. + * + * This project is meant to fill in where LibTomMath + * falls short. That is speed ;-) + * + * This project is public domain and free for all purposes. + * + * Tom St Denis, [email protected] + */ +#include <tfm.h> + +/* unsigned addition */ +void s_fp_add(fp_int *a, fp_int *b, fp_int *c) +{ + int x, y, oldused; + register fp_word t; + + y = MAX(a->used, b->used); + oldused = c->used; + c->used = y; + + t = 0; + for (x = 0; x < y; x++) { + t += ((fp_word)a->dp[x]) + ((fp_word)b->dp[x]); + c->dp[x] = (fp_digit)t; + t >>= DIGIT_BIT; + } + if (t != 0 && x < FP_SIZE) { + c->dp[c->used++] = (fp_digit)t; + ++x; + } + + c->used = x; + for (; x < oldused; x++) { + c->dp[x] = 0; + } + fp_clamp(c); +} + +/* $Source$ */ +/* $Revision$ */ +/* $Date$ */