Import code from previous AssetBuilder version

2025-06-10 14:58:10 -05:00 · 2019-09-24 10:45:09 +02:00
parent 5609557516
commit 0d8432d4f7
919 changed files with 154412 additions and 26 deletions
--- a/thirdparty/libtommath/bn_mp_exptmod.c
+++ b/thirdparty/libtommath/bn_mp_exptmod.c
@ -0,0 +1,109 @@
+#include "tommath_private.h"
+#ifdef BN_MP_EXPTMOD_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
+ */
+
+
+/* this is a shell function that calls either the normal or Montgomery
+ * exptmod functions.  Originally the call to the montgomery code was
+ * embedded in the normal function but that wasted alot of stack space
+ * for nothing (since 99% of the time the Montgomery code would be called)
+ */
+int mp_exptmod(const mp_int *G, const mp_int *X, const mp_int *P, mp_int *Y)
+{
+   int dr;
+
+   /* modulus P must be positive */
+   if (P->sign == MP_NEG) {
+      return MP_VAL;
+   }
+
+   /* if exponent X is negative we have to recurse */
+   if (X->sign == MP_NEG) {
+#ifdef BN_MP_INVMOD_C
+      mp_int tmpG, tmpX;
+      int err;
+
+      /* first compute 1/G mod P */
+      if ((err = mp_init(&tmpG)) != MP_OKAY) {
+         return err;
+      }
+      if ((err = mp_invmod(G, P, &tmpG)) != MP_OKAY) {
+         mp_clear(&tmpG);
+         return err;
+      }
+
+      /* now get |X| */
+      if ((err = mp_init(&tmpX)) != MP_OKAY) {
+         mp_clear(&tmpG);
+         return err;
+      }
+      if ((err = mp_abs(X, &tmpX)) != MP_OKAY) {
+         mp_clear_multi(&tmpG, &tmpX, NULL);
+         return err;
+      }
+
+      /* and now compute (1/G)**|X| instead of G**X [X < 0] */
+      err = mp_exptmod(&tmpG, &tmpX, P, Y);
+      mp_clear_multi(&tmpG, &tmpX, NULL);
+      return err;
+#else
+      /* no invmod */
+      return MP_VAL;
+#endif
+   }
+
+   /* modified diminished radix reduction */
+#if defined(BN_MP_REDUCE_IS_2K_L_C) && defined(BN_MP_REDUCE_2K_L_C) && defined(BN_S_MP_EXPTMOD_C)
+   if (mp_reduce_is_2k_l(P) == MP_YES) {
+      return s_mp_exptmod(G, X, P, Y, 1);
+   }
+#endif
+
+#ifdef BN_MP_DR_IS_MODULUS_C
+   /* is it a DR modulus? */
+   dr = mp_dr_is_modulus(P);
+#else
+   /* default to no */
+   dr = 0;
+#endif
+
+#ifdef BN_MP_REDUCE_IS_2K_C
+   /* if not, is it a unrestricted DR modulus? */
+   if (dr == 0) {
+      dr = mp_reduce_is_2k(P) << 1;
+   }
+#endif
+
+   /* if the modulus is odd or dr != 0 use the montgomery method */
+#ifdef BN_MP_EXPTMOD_FAST_C
+   if ((mp_isodd(P) == MP_YES) || (dr !=  0)) {
+      return mp_exptmod_fast(G, X, P, Y, dr);
+   } else {
+#endif
+#ifdef BN_S_MP_EXPTMOD_C
+      /* otherwise use the generic Barrett reduction technique */
+      return s_mp_exptmod(G, X, P, Y, 0);
+#else
+      /* no exptmod for evens */
+      return MP_VAL;
+#endif
+#ifdef BN_MP_EXPTMOD_FAST_C
+   }
+#endif
+}
+
+#endif
+
+/* ref:         HEAD -> master, tag: v1.1.0 */
+/* git commit:  08549ad6bc8b0cede0b357a9c341c5c6473a9c55 */
+/* commit time: 2019-01-28 20:32:32 +0100 */