mul_i.h
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上传日期:2022-08-06
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- /* mpz_mul_ui/si (product, multiplier, small_multiplicand) -- Set PRODUCT to
- MULTIPLICATOR times SMALL_MULTIPLICAND.
- Copyright 1991, 1993, 1994, 1996, 2000, 2001, 2002, 2005, 2008 Free Software
- Foundation, Inc.
- This file is part of the GNU MP Library.
- The GNU MP Library is free software; you can redistribute it and/or modify
- it under the terms of the GNU Lesser General Public License as published by
- the Free Software Foundation; either version 3 of the License, or (at your
- option) any later version.
- The GNU MP Library is distributed in the hope that it will be useful, but
- WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
- License for more details.
- You should have received a copy of the GNU Lesser General Public License
- along with the GNU MP Library. If not, see http://www.gnu.org/licenses/. */
- #include "gmp.h"
- #include "gmp-impl.h"
- #ifdef OPERATION_mul_si
- #define FUNCTION mpz_mul_si
- #define MULTIPLICAND_UNSIGNED
- #define MULTIPLICAND_ABS(x) ((unsigned long) ABS(x))
- #endif
- #ifdef OPERATION_mul_ui
- #define FUNCTION mpz_mul_ui
- #define MULTIPLICAND_UNSIGNED unsigned
- #define MULTIPLICAND_ABS(x) x
- #endif
- #ifndef FUNCTION
- Error, error, unrecognised OPERATION
- #endif
- void
- FUNCTION (mpz_ptr prod, mpz_srcptr mult,
- MULTIPLICAND_UNSIGNED long int small_mult)
- {
- mp_size_t size = SIZ(mult);
- mp_size_t sign_product = size;
- mp_limb_t sml;
- mp_limb_t cy;
- mp_ptr pp;
- if (size == 0 || small_mult == 0)
- {
- SIZ(prod) = 0;
- return;
- }
- size = ABS (size);
- sml = MULTIPLICAND_ABS (small_mult);
- if (sml <= GMP_NUMB_MAX)
- {
- MPZ_REALLOC (prod, size + 1);
- pp = PTR(prod);
- cy = mpn_mul_1 (pp, PTR(mult), size, sml & GMP_NUMB_MASK);
- pp[size] = cy;
- size += cy != 0;
- }
- #if GMP_NAIL_BITS != 0
- else
- {
- /* Operand too large for the current nails size. Use temporary for
- intermediate products, to allow prod and mult being identical. */
- mp_ptr tp;
- TMP_DECL;
- TMP_MARK;
- tp = TMP_ALLOC_LIMBS (size + 2);
- cy = mpn_mul_1 (tp, PTR(mult), size, sml & GMP_NUMB_MASK);
- tp[size] = cy;
- cy = mpn_addmul_1 (tp + 1, PTR(mult), size, sml >> GMP_NUMB_BITS);
- tp[size + 1] = cy;
- size += 2;
- MPN_NORMALIZE_NOT_ZERO (tp, size); /* too general, need to trim one or two limb */
- MPZ_REALLOC (prod, size);
- pp = PTR(prod);
- MPN_COPY (pp, tp, size);
- TMP_FREE;
- }
- #endif
- SIZ(prod) = ((sign_product < 0) ^ (small_mult < 0)) ? -size : size;
- }