merge from main

--HG--
branch : fuzz

1 files changed, 61 insertions, 78 deletions

diff --git a/libtommath/bn_mp_reduce.c b/libtommath/bn_mp_reduce.c
index 367383f..3c669d4 100644
--- a/libtommath/bn_mp_reduce.c
+++ b/libtommath/bn_mp_reduce.c
@@ -1,100 +1,83 @@
-#include <tommath_private.h>
+#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.
- *
- * The library is free for all purposes without any express
- * guarantee it works.
- *
- * Tom St Denis, tstdenis82@gmail.com, http://libtom.org
- */
+/* 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, mp_int * m, 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_int  q;
+   mp_err  err;
+   int     um = m->used;
 
-  /* q = x */
-  if ((res = mp_init_copy (&q, x)) != MP_OKAY) {
-    return res;
-  }
+   /* q = x */
+   if ((err = mp_init_copy(&q, x)) != MP_OKAY) {
+      return err;
+   }
 
-  /* q1 = x / b**(k-1)  */
-  mp_rshd (&q, um - 1);
+   /* 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) {
-      goto CLEANUP;
-    }
-  } else {
-#ifdef BN_S_MP_MUL_HIGH_DIGS_C
-    if ((res = 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) {
+   /* according to HAC this optimization is ok */
+   if ((mp_digit)um > ((mp_digit)1 << (MP_DIGIT_BIT - 1))) {
+      if ((err = mp_mul(&q, mu, &q)) != MP_OKAY) {
+         goto CLEANUP;
+      }
+   } else if (MP_HAS(S_MP_MUL_HIGH_DIGS)) {
+      if ((err = s_mp_mul_high_digs(&q, mu, &q, um)) != MP_OKAY) {
+         goto CLEANUP;
+      }
+   } 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 {
+      err = MP_VAL;
       goto CLEANUP;
-    }
-#else
-    {
-      res = MP_VAL;
-      goto CLEANUP;
-    }
-#endif
-  }
-
-  /* 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) {
-    goto CLEANUP;
-  }
+   /* q3 = q2 / b**(k+1) */
+   mp_rshd(&q, um + 1);
 
-  /* q = q * m mod b**(k+1), quick (no division) */
-  if ((res = 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) {
-    goto CLEANUP;
-  }
-
-  /* If x < 0, add b**(k+1) to it */
-  if (mp_cmp_d (x, 0) == MP_LT) {
-    mp_set (&q, 1);
-    if ((res = mp_lshd (&q, um + 1)) != MP_OKAY)
+   /* x = x mod b**(k+1), quick (no division) */
+   if ((err = mp_mod_2d(x, MP_DIGIT_BIT * (um + 1), x)) != MP_OKAY) {
       goto CLEANUP;
-    if ((res = mp_add (x, &q, x)) != MP_OKAY)
+   }
+
+   /* q = q * m mod b**(k+1), quick (no division) */
+   if ((err = s_mp_mul_digs(&q, m, &q, um + 1)) != 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) {
+   /* x = x - q */
+   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 ((err = mp_lshd(&q, um + 1)) != MP_OKAY) {
+         goto CLEANUP;
+      }
+      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 ((err = s_mp_sub(x, m, x)) != MP_OKAY) {
+         goto CLEANUP;
+      }
+   }
 
 CLEANUP:
-  mp_clear (&q);
+   mp_clear(&q);
 
-  return res;
+   return err;
 }
 #endif
-
-/* ref:         $Format:%D$ */
-/* git commit:  $Format:%H$ */
-/* commit time: $Format:%ai$ */