140 lines
3.2 KiB
C
140 lines
3.2 KiB
C
/* 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, tomstdenis@gmail.com
|
|
*/
|
|
#include <tfm_private.h>
|
|
|
|
/* c = a * b */
|
|
void fp_mul(fp_int *A, fp_int *B, fp_int *C)
|
|
{
|
|
int y, old_used;
|
|
#if FP_SIZE >= 48
|
|
int yy;
|
|
#endif
|
|
|
|
old_used = C->used;
|
|
|
|
/* call generic if we're out of range */
|
|
if (A->used + B->used > FP_SIZE) {
|
|
fp_mul_comba(A, B, C);
|
|
goto clean;
|
|
}
|
|
|
|
y = MAX(A->used, B->used);
|
|
#if FP_SIZE >= 48
|
|
yy = MIN(A->used, B->used);
|
|
#endif
|
|
/* pick a comba (unrolled 4/8/16/32 x or rolled) based on the size
|
|
of the largest input. We also want to avoid doing excess mults if the
|
|
inputs are not close to the next power of two. That is, for example,
|
|
if say y=17 then we would do (32-17)^2 = 225 unneeded multiplications
|
|
*/
|
|
|
|
#if defined(TFM_MUL3) && FP_SIZE >= 6
|
|
if (y <= 3) {
|
|
fp_mul_comba3(A,B,C);
|
|
goto clean;
|
|
}
|
|
#endif
|
|
#if defined(TFM_MUL4) && FP_SIZE >= 8
|
|
if (y == 4) {
|
|
fp_mul_comba4(A,B,C);
|
|
goto clean;
|
|
}
|
|
#endif
|
|
#if defined(TFM_MUL6) && FP_SIZE >= 12
|
|
if (y <= 6) {
|
|
fp_mul_comba6(A,B,C);
|
|
goto clean;
|
|
}
|
|
#endif
|
|
#if defined(TFM_MUL7) && FP_SIZE >= 14
|
|
if (y == 7) {
|
|
fp_mul_comba7(A,B,C);
|
|
goto clean;
|
|
}
|
|
#endif
|
|
#if defined(TFM_MUL8) && FP_SIZE >= 16
|
|
if (y == 8) {
|
|
fp_mul_comba8(A,B,C);
|
|
goto clean;
|
|
}
|
|
#endif
|
|
#if defined(TFM_MUL9) && FP_SIZE >= 18
|
|
if (y == 9) {
|
|
fp_mul_comba9(A,B,C);
|
|
goto clean;
|
|
}
|
|
#endif
|
|
#if defined(TFM_MUL12) && FP_SIZE >= 24
|
|
if (y <= 12) {
|
|
fp_mul_comba12(A,B,C);
|
|
goto clean;
|
|
}
|
|
#endif
|
|
#if defined(TFM_MUL17) && FP_SIZE >= 34
|
|
if (y <= 17) {
|
|
fp_mul_comba17(A,B,C);
|
|
goto clean;
|
|
}
|
|
#endif
|
|
|
|
#if defined(TFM_SMALL_SET) && FP_SIZE >= 32
|
|
if (y <= 16) {
|
|
fp_mul_comba_small(A,B,C);
|
|
goto clean;
|
|
}
|
|
#endif
|
|
#if defined(TFM_MUL20) && FP_SIZE >= 40
|
|
if (y <= 20) {
|
|
fp_mul_comba20(A,B,C);
|
|
goto clean;
|
|
}
|
|
#endif
|
|
#if defined(TFM_MUL24) && FP_SIZE >= 48
|
|
if (yy >= 16 && y <= 24) {
|
|
fp_mul_comba24(A,B,C);
|
|
goto clean;
|
|
}
|
|
#endif
|
|
#if defined(TFM_MUL28) && FP_SIZE >= 56
|
|
if (yy >= 20 && y <= 28) {
|
|
fp_mul_comba28(A,B,C);
|
|
goto clean;
|
|
}
|
|
#endif
|
|
#if defined(TFM_MUL32) && FP_SIZE >= 64
|
|
if (yy >= 24 && y <= 32) {
|
|
fp_mul_comba32(A,B,C);
|
|
goto clean;
|
|
}
|
|
#endif
|
|
#if defined(TFM_MUL48) && FP_SIZE >= 96
|
|
if (yy >= 40 && y <= 48) {
|
|
fp_mul_comba48(A,B,C);
|
|
goto clean;
|
|
}
|
|
#endif
|
|
#if defined(TFM_MUL64) && FP_SIZE >= 128
|
|
if (yy >= 56 && y <= 64) {
|
|
fp_mul_comba64(A,B,C);
|
|
goto clean;
|
|
}
|
|
#endif
|
|
fp_mul_comba(A,B,C);
|
|
clean:
|
|
for (y = C->used; y < old_used; y++) {
|
|
C->dp[y] = 0;
|
|
}
|
|
}
|
|
|
|
|
|
/* $Source: /cvs/libtom/tomsfastmath/src/mul/fp_mul.c,v $ */
|
|
/* $Revision: 1.1 $ */
|
|
/* $Date: 2006/12/31 21:25:53 $ */
|