Mercurial > dropbear
diff tomsfastmath/src/addsub/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/fp_add.c Wed Nov 23 18:10:20 2011 +0700 @@ -0,0 +1,43 @@ +/* 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> + +void fp_add(fp_int *a, fp_int *b, fp_int *c) +{ + int sa, sb; + + /* get sign of both inputs */ + sa = a->sign; + sb = b->sign; + + /* handle two cases, not four */ + if (sa == sb) { + /* both positive or both negative */ + /* add their magnitudes, copy the sign */ + c->sign = sa; + s_fp_add (a, b, c); + } else { + /* one positive, the other negative */ + /* subtract the one with the greater magnitude from */ + /* the one of the lesser magnitude. The result gets */ + /* the sign of the one with the greater magnitude. */ + if (fp_cmp_mag (a, b) == FP_LT) { + c->sign = sb; + s_fp_sub (b, a, c); + } else { + c->sign = sa; + s_fp_sub (a, b, c); + } + } +} + +/* $Source$ */ +/* $Revision$ */ +/* $Date$ */