summaryrefslogtreecommitdiffstats
path: root/libtommath/bn_mp_mul_2d.c
diff options
context:
space:
mode:
Diffstat (limited to 'libtommath/bn_mp_mul_2d.c')
-rw-r--r--libtommath/bn_mp_mul_2d.c108
1 files changed, 55 insertions, 53 deletions
diff --git a/libtommath/bn_mp_mul_2d.c b/libtommath/bn_mp_mul_2d.c
index 4ac2e4e..42c6535 100644
--- a/libtommath/bn_mp_mul_2d.c
+++ b/libtommath/bn_mp_mul_2d.c
@@ -1,4 +1,4 @@
-#include <tommath.h>
+#include "tommath_private.h"
#ifdef BN_MP_MUL_2D_C
/* LibTomMath, multiple-precision integer library -- Tom St Denis
*
@@ -11,71 +11,73 @@
*
* The library is free for all purposes without any express
* guarantee it works.
- *
- * Tom St Denis, tomstdenis@gmail.com, http://math.libtomcrypt.com
*/
/* shift left by a certain bit count */
-int mp_mul_2d (const mp_int * a, int b, mp_int * c)
+int mp_mul_2d(const mp_int *a, int b, mp_int *c)
{
- mp_digit d;
- int res;
+ mp_digit d;
+ int res;
+
+ /* copy */
+ if (a != c) {
+ if ((res = mp_copy(a, c)) != MP_OKAY) {
+ return res;
+ }
+ }
- /* copy */
- if (a != c) {
- if ((res = mp_copy (a, c)) != MP_OKAY) {
- return res;
- }
- }
+ if (c->alloc < (c->used + (b / DIGIT_BIT) + 1)) {
+ if ((res = mp_grow(c, c->used + (b / DIGIT_BIT) + 1)) != MP_OKAY) {
+ return res;
+ }
+ }
- if (c->alloc < (int)(c->used + b/DIGIT_BIT + 1)) {
- if ((res = mp_grow (c, c->used + b / DIGIT_BIT + 1)) != MP_OKAY) {
- return res;
- }
- }
+ /* shift by as many digits in the bit count */
+ if (b >= DIGIT_BIT) {
+ if ((res = mp_lshd(c, b / DIGIT_BIT)) != MP_OKAY) {
+ return res;
+ }
+ }
- /* shift by as many digits in the bit count */
- if (b >= (int)DIGIT_BIT) {
- if ((res = mp_lshd (c, b / DIGIT_BIT)) != MP_OKAY) {
- return res;
- }
- }
+ /* shift any bit count < DIGIT_BIT */
+ d = (mp_digit)(b % DIGIT_BIT);
+ if (d != 0u) {
+ mp_digit *tmpc, shift, mask, r, rr;
+ int x;
- /* shift any bit count < DIGIT_BIT */
- d = (mp_digit) (b % DIGIT_BIT);
- if (d != 0) {
- register mp_digit *tmpc, shift, mask, r, rr;
- register int x;
+ /* bitmask for carries */
+ mask = ((mp_digit)1 << d) - (mp_digit)1;
- /* bitmask for carries */
- mask = (((mp_digit)1) << d) - 1;
+ /* shift for msbs */
+ shift = (mp_digit)DIGIT_BIT - d;
- /* shift for msbs */
- shift = DIGIT_BIT - d;
+ /* alias */
+ tmpc = c->dp;
- /* alias */
- tmpc = c->dp;
+ /* carry */
+ r = 0;
+ for (x = 0; x < c->used; x++) {
+ /* get the higher bits of the current word */
+ rr = (*tmpc >> shift) & mask;
- /* carry */
- r = 0;
- for (x = 0; x < c->used; x++) {
- /* get the higher bits of the current word */
- rr = (*tmpc >> shift) & mask;
+ /* shift the current word and OR in the carry */
+ *tmpc = ((*tmpc << d) | r) & MP_MASK;
+ ++tmpc;
- /* shift the current word and OR in the carry */
- *tmpc = ((*tmpc << d) | r) & MP_MASK;
- ++tmpc;
+ /* set the carry to the carry bits of the current word */
+ r = rr;
+ }
- /* set the carry to the carry bits of the current word */
- r = rr;
- }
-
- /* set final carry */
- if (r != 0) {
- c->dp[(c->used)++] = r;
- }
- }
- mp_clamp (c);
- return MP_OKAY;
+ /* set final carry */
+ if (r != 0u) {
+ c->dp[(c->used)++] = r;
+ }
+ }
+ mp_clamp(c);
+ return MP_OKAY;
}
#endif
+
+/* ref: $Format:%D$ */
+/* git commit: $Format:%H$ */
+/* commit time: $Format:%ai$ */