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-rw-r--r--libtommath/bn_mp_reduce.c64
1 files changed, 25 insertions, 39 deletions
diff --git a/libtommath/bn_mp_reduce.c b/libtommath/bn_mp_reduce.c
index 9cb9d2a..3c669d4 100644
--- a/libtommath/bn_mp_reduce.c
+++ b/libtommath/bn_mp_reduce.c
@@ -1,86 +1,76 @@
#include "tommath_private.h"
#ifdef BN_MP_REDUCE_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
- */
+/* LibTomMath, multiple-precision integer library -- Tom St Denis */
+/* SPDX-License-Identifier: Unlicense */
/* reduces x mod m, assumes 0 < x < m**2, mu is
* precomputed via mp_reduce_setup.
* From HAC pp.604 Algorithm 14.42
*/
-int mp_reduce(mp_int *x, const mp_int *m, const mp_int *mu)
+mp_err mp_reduce(mp_int *x, const mp_int *m, const mp_int *mu)
{
mp_int q;
- int res, um = m->used;
+ mp_err err;
+ int um = m->used;
/* q = x */
- if ((res = mp_init_copy(&q, x)) != MP_OKAY) {
- return res;
+ if ((err = mp_init_copy(&q, x)) != MP_OKAY) {
+ return err;
}
/* q1 = x / b**(k-1) */
mp_rshd(&q, um - 1);
/* according to HAC this optimization is ok */
- if ((mp_digit)um > ((mp_digit)1 << (DIGIT_BIT - 1))) {
- if ((res = mp_mul(&q, mu, &q)) != MP_OKAY) {
+ if ((mp_digit)um > ((mp_digit)1 << (MP_DIGIT_BIT - 1))) {
+ if ((err = mp_mul(&q, mu, &q)) != MP_OKAY) {
goto CLEANUP;
}
- } else {
-#ifdef BN_S_MP_MUL_HIGH_DIGS_C
- if ((res = s_mp_mul_high_digs(&q, mu, &q, um)) != MP_OKAY) {
+ } else if (MP_HAS(S_MP_MUL_HIGH_DIGS)) {
+ if ((err = s_mp_mul_high_digs(&q, mu, &q, um)) != MP_OKAY) {
goto CLEANUP;
}
-#elif defined(BN_FAST_S_MP_MUL_HIGH_DIGS_C)
- if ((res = fast_s_mp_mul_high_digs(&q, mu, &q, um)) != MP_OKAY) {
+ } else if (MP_HAS(S_MP_MUL_HIGH_DIGS_FAST)) {
+ if ((err = s_mp_mul_high_digs_fast(&q, mu, &q, um)) != MP_OKAY) {
goto CLEANUP;
}
-#else
- {
- res = MP_VAL;
- goto CLEANUP;
- }
-#endif
+ } else {
+ err = MP_VAL;
+ goto CLEANUP;
}
/* q3 = q2 / b**(k+1) */
mp_rshd(&q, um + 1);
/* x = x mod b**(k+1), quick (no division) */
- if ((res = mp_mod_2d(x, DIGIT_BIT * (um + 1), x)) != MP_OKAY) {
+ if ((err = mp_mod_2d(x, MP_DIGIT_BIT * (um + 1), x)) != MP_OKAY) {
goto CLEANUP;
}
/* q = q * m mod b**(k+1), quick (no division) */
- if ((res = s_mp_mul_digs(&q, m, &q, um + 1)) != MP_OKAY) {
+ if ((err = s_mp_mul_digs(&q, m, &q, um + 1)) != MP_OKAY) {
goto CLEANUP;
}
/* x = x - q */
- if ((res = mp_sub(x, &q, x)) != MP_OKAY) {
+ if ((err = mp_sub(x, &q, x)) != MP_OKAY) {
goto CLEANUP;
}
/* If x < 0, add b**(k+1) to it */
if (mp_cmp_d(x, 0uL) == MP_LT) {
mp_set(&q, 1uL);
- if ((res = mp_lshd(&q, um + 1)) != MP_OKAY)
+ if ((err = mp_lshd(&q, um + 1)) != MP_OKAY) {
goto CLEANUP;
- if ((res = mp_add(x, &q, x)) != MP_OKAY)
+ }
+ if ((err = mp_add(x, &q, x)) != MP_OKAY) {
goto CLEANUP;
+ }
}
/* Back off if it's too big */
while (mp_cmp(x, m) != MP_LT) {
- if ((res = s_mp_sub(x, m, x)) != MP_OKAY) {
+ if ((err = s_mp_sub(x, m, x)) != MP_OKAY) {
goto CLEANUP;
}
}
@@ -88,10 +78,6 @@ int mp_reduce(mp_int *x, const mp_int *m, const mp_int *mu)
CLEANUP:
mp_clear(&q);
- return res;
+ return err;
}
#endif
-
-/* ref: HEAD -> master, tag: v1.1.0 */
-/* git commit: 08549ad6bc8b0cede0b357a9c341c5c6473a9c55 */
-/* commit time: 2019-01-28 20:32:32 +0100 */