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-rw-r--r--libtommath/bn_mp_and.c84
1 files changed, 43 insertions, 41 deletions
diff --git a/libtommath/bn_mp_and.c b/libtommath/bn_mp_and.c
index 789bb58..10fe28b 100644
--- a/libtommath/bn_mp_and.c
+++ b/libtommath/bn_mp_and.c
@@ -1,54 +1,56 @@
#include "tommath_private.h"
#ifdef BN_MP_AND_C
-/* LibTomMath, multiple-precision integer library -- Tom St Denis
- *
- * LibTomMath is a library that provides multiple-precision
- * integer arithmetic as well as number theoretic functionality.
- *
- * The library was designed directly after the MPI library by
- * Michael Fromberger but has been written from scratch with
- * additional optimizations in place.
- *
- * SPDX-License-Identifier: Unlicense
- */
-
-/* AND two ints together */
-int mp_and(const mp_int *a, const mp_int *b, mp_int *c)
+/* LibTomMath, multiple-precision integer library -- Tom St Denis */
+/* SPDX-License-Identifier: Unlicense */
+
+/* two complement and */
+mp_err mp_and(const mp_int *a, const mp_int *b, mp_int *c)
{
- int res, ix, px;
- mp_int t;
- const mp_int *x;
+ int used = MAX(a->used, b->used) + 1, i;
+ mp_err err;
+ mp_digit ac = 1, bc = 1, cc = 1;
+ mp_sign csign = ((a->sign == MP_NEG) && (b->sign == MP_NEG)) ? MP_NEG : MP_ZPOS;
- if (a->used > b->used) {
- if ((res = mp_init_copy(&t, a)) != MP_OKAY) {
- return res;
- }
- px = b->used;
- x = b;
- } else {
- if ((res = mp_init_copy(&t, b)) != MP_OKAY) {
- return res;
+ if (c->alloc < used) {
+ if ((err = mp_grow(c, used)) != MP_OKAY) {
+ return err;
}
- px = a->used;
- x = a;
}
- for (ix = 0; ix < px; ix++) {
- t.dp[ix] &= x->dp[ix];
- }
+ for (i = 0; i < used; i++) {
+ mp_digit x, y;
+
+ /* convert to two complement if negative */
+ if (a->sign == MP_NEG) {
+ ac += (i >= a->used) ? MP_MASK : (~a->dp[i] & MP_MASK);
+ x = ac & MP_MASK;
+ ac >>= MP_DIGIT_BIT;
+ } else {
+ x = (i >= a->used) ? 0uL : a->dp[i];
+ }
- /* zero digits above the last from the smallest mp_int */
- for (; ix < t.used; ix++) {
- t.dp[ix] = 0;
+ /* convert to two complement if negative */
+ if (b->sign == MP_NEG) {
+ bc += (i >= b->used) ? MP_MASK : (~b->dp[i] & MP_MASK);
+ y = bc & MP_MASK;
+ bc >>= MP_DIGIT_BIT;
+ } else {
+ y = (i >= b->used) ? 0uL : b->dp[i];
+ }
+
+ c->dp[i] = x & y;
+
+ /* convert to to sign-magnitude if negative */
+ if (csign == MP_NEG) {
+ cc += ~c->dp[i] & MP_MASK;
+ c->dp[i] = cc & MP_MASK;
+ cc >>= MP_DIGIT_BIT;
+ }
}
- mp_clamp(&t);
- mp_exch(c, &t);
- mp_clear(&t);
+ c->used = used;
+ c->sign = csign;
+ mp_clamp(c);
return MP_OKAY;
}
#endif
-
-/* ref: $Format:%D$ */
-/* git commit: $Format:%H$ */
-/* commit time: $Format:%ai$ */