1 /* TomsFastMath, a fast ISO C bignum library.
3 * This project is meant to fill in where LibTomMath
4 * falls short. That is speed ;-)
6 * This project is public domain and free for all purposes.
8 * Tom St Denis, tomstdenis@gmail.com
10 #include <tfm_private.h>
12 /* unsigned subtraction ||a|| >= ||b|| ALWAYS! */
13 void s_fp_sub(fp_int *a, fp_int *b, fp_int *c)
15 int x, oldbused, oldused;
22 for (x = 0; x < oldbused; x++) {
23 t = ((fp_word)a->dp[x]) - (((fp_word)b->dp[x]) + t);
24 c->dp[x] = (fp_digit)t;
25 t = (t >> DIGIT_BIT)&1;
27 for (; x < a->used; x++) {
28 t = ((fp_word)a->dp[x]) - t;
29 c->dp[x] = (fp_digit)t;
30 t = (t >> DIGIT_BIT)&1;
32 for (; x < oldused; x++) {