diff options
Diffstat (limited to 'libtommath/bn_mp_montgomery_reduce.c')
| -rw-r--r-- | libtommath/bn_mp_montgomery_reduce.c | 39 |
1 files changed, 13 insertions, 26 deletions
diff --git a/libtommath/bn_mp_montgomery_reduce.c b/libtommath/bn_mp_montgomery_reduce.c index e3b02cd..ffe8341 100644 --- a/libtommath/bn_mp_montgomery_reduce.c +++ b/libtommath/bn_mp_montgomery_reduce.c @@ -1,21 +1,13 @@ #include "tommath_private.h" #ifdef BN_MP_MONTGOMERY_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 */ /* computes xR**-1 == x (mod N) via Montgomery Reduction */ -int mp_montgomery_reduce(mp_int *x, const mp_int *n, mp_digit rho) +mp_err mp_montgomery_reduce(mp_int *x, const mp_int *n, mp_digit rho) { - int ix, res, digs; + int ix, digs; + mp_err err; mp_digit mu; /* can the fast reduction [comba] method be used? @@ -25,17 +17,16 @@ int mp_montgomery_reduce(mp_int *x, const mp_int *n, mp_digit rho) * are fixed up in the inner loop. */ digs = (n->used * 2) + 1; - if ((digs < (int)MP_WARRAY) && - (x->used <= (int)MP_WARRAY) && - (n->used < - (int)(1u << (((size_t)CHAR_BIT * sizeof(mp_word)) - (2u * (size_t)DIGIT_BIT))))) { - return fast_mp_montgomery_reduce(x, n, rho); + if ((digs < MP_WARRAY) && + (x->used <= MP_WARRAY) && + (n->used < MP_MAXFAST)) { + return s_mp_montgomery_reduce_fast(x, n, rho); } /* grow the input as required */ if (x->alloc < digs) { - if ((res = mp_grow(x, digs)) != MP_OKAY) { - return res; + if ((err = mp_grow(x, digs)) != MP_OKAY) { + return err; } } x->used = digs; @@ -73,7 +64,7 @@ int mp_montgomery_reduce(mp_int *x, const mp_int *n, mp_digit rho) (mp_word)u + (mp_word)*tmpx; /* get carry */ - u = (mp_digit)(r >> (mp_word)DIGIT_BIT); + u = (mp_digit)(r >> (mp_word)MP_DIGIT_BIT); /* fix digit */ *tmpx++ = (mp_digit)(r & (mp_word)MP_MASK); @@ -84,7 +75,7 @@ int mp_montgomery_reduce(mp_int *x, const mp_int *n, mp_digit rho) /* propagate carries upwards as required*/ while (u != 0u) { *tmpx += u; - u = *tmpx >> DIGIT_BIT; + u = *tmpx >> MP_DIGIT_BIT; *tmpx++ &= MP_MASK; } } @@ -109,7 +100,3 @@ int mp_montgomery_reduce(mp_int *x, const mp_int *n, mp_digit rho) return MP_OKAY; } #endif - -/* ref: HEAD -> master, tag: v1.1.0 */ -/* git commit: 08549ad6bc8b0cede0b357a9c341c5c6473a9c55 */ -/* commit time: 2019-01-28 20:32:32 +0100 */ |