ior.c
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上传日期:2022-08-06
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文件大小:5k
- /* mpz_ior -- Logical inclusive or.
- Copyright 1991, 1993, 1994, 1996, 1997, 2000, 2001, 2005 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"
- void
- mpz_ior (mpz_ptr res, mpz_srcptr op1, mpz_srcptr op2)
- {
- mp_srcptr op1_ptr, op2_ptr;
- mp_size_t op1_size, op2_size;
- mp_ptr res_ptr;
- mp_size_t res_size;
- mp_size_t i;
- TMP_DECL;
- TMP_MARK;
- op1_size = SIZ(op1);
- op2_size = SIZ(op2);
- op1_ptr = PTR(op1);
- op2_ptr = PTR(op2);
- res_ptr = PTR(res);
- if (op1_size >= 0)
- {
- if (op2_size >= 0)
- {
- if (op1_size >= op2_size)
- {
- if (ALLOC(res) < op1_size)
- {
- _mpz_realloc (res, op1_size);
- /* No overlapping possible: op1_ptr = PTR(op1); */
- op2_ptr = PTR(op2);
- res_ptr = PTR(res);
- }
- if (res_ptr != op1_ptr)
- MPN_COPY (res_ptr + op2_size, op1_ptr + op2_size,
- op1_size - op2_size);
- for (i = op2_size - 1; i >= 0; i--)
- res_ptr[i] = op1_ptr[i] | op2_ptr[i];
- res_size = op1_size;
- }
- else
- {
- if (ALLOC(res) < op2_size)
- {
- _mpz_realloc (res, op2_size);
- op1_ptr = PTR(op1);
- /* No overlapping possible: op2_ptr = PTR(op2); */
- res_ptr = PTR(res);
- }
- if (res_ptr != op2_ptr)
- MPN_COPY (res_ptr + op1_size, op2_ptr + op1_size,
- op2_size - op1_size);
- for (i = op1_size - 1; i >= 0; i--)
- res_ptr[i] = op1_ptr[i] | op2_ptr[i];
- res_size = op2_size;
- }
- SIZ(res) = res_size;
- return;
- }
- else /* op2_size < 0 */
- {
- /* Fall through to the code at the end of the function. */
- }
- }
- else
- {
- if (op2_size < 0)
- {
- mp_ptr opx;
- mp_limb_t cy;
- /* Both operands are negative, so will be the result.
- -((-OP1) | (-OP2)) = -(~(OP1 - 1) | ~(OP2 - 1)) =
- = ~(~(OP1 - 1) | ~(OP2 - 1)) + 1 =
- = ((OP1 - 1) & (OP2 - 1)) + 1 */
- op1_size = -op1_size;
- op2_size = -op2_size;
- res_size = MIN (op1_size, op2_size);
- /* Possible optimization: Decrease mpn_sub precision,
- as we won't use the entire res of both. */
- opx = TMP_ALLOC_LIMBS (res_size);
- mpn_sub_1 (opx, op1_ptr, res_size, (mp_limb_t) 1);
- op1_ptr = opx;
- opx = TMP_ALLOC_LIMBS (res_size);
- mpn_sub_1 (opx, op2_ptr, res_size, (mp_limb_t) 1);
- op2_ptr = opx;
- if (ALLOC(res) < res_size)
- {
- _mpz_realloc (res, res_size);
- /* op1_ptr and op2_ptr point to temporary space. */
- res_ptr = PTR(res);
- }
- /* First loop finds the size of the result. */
- for (i = res_size - 1; i >= 0; i--)
- if ((op1_ptr[i] & op2_ptr[i]) != 0)
- break;
- res_size = i + 1;
- if (res_size != 0)
- {
- /* Second loop computes the real result. */
- for (i = res_size - 1; i >= 0; i--)
- res_ptr[i] = op1_ptr[i] & op2_ptr[i];
- cy = mpn_add_1 (res_ptr, res_ptr, res_size, (mp_limb_t) 1);
- if (cy)
- {
- res_ptr[res_size] = cy;
- res_size++;
- }
- }
- else
- {
- res_ptr[0] = 1;
- res_size = 1;
- }
- SIZ(res) = -res_size;
- TMP_FREE;
- return;
- }
- else
- {
- /* We should compute -OP1 | OP2. Swap OP1 and OP2 and fall
- through to the code that handles OP1 | -OP2. */
- MPZ_SRCPTR_SWAP (op1, op2);
- MPN_SRCPTR_SWAP (op1_ptr,op1_size, op2_ptr,op2_size);
- }
- }
- {
- mp_ptr opx;
- mp_limb_t cy;
- mp_size_t res_alloc;
- mp_size_t count;
- /* Operand 2 negative, so will be the result.
- -(OP1 | (-OP2)) = -(OP1 | ~(OP2 - 1)) =
- = ~(OP1 | ~(OP2 - 1)) + 1 =
- = (~OP1 & (OP2 - 1)) + 1 */
- op2_size = -op2_size;
- res_alloc = op2_size;
- opx = TMP_ALLOC_LIMBS (op2_size);
- mpn_sub_1 (opx, op2_ptr, op2_size, (mp_limb_t) 1);
- op2_ptr = opx;
- op2_size -= op2_ptr[op2_size - 1] == 0;
- if (ALLOC(res) < res_alloc)
- {
- _mpz_realloc (res, res_alloc);
- op1_ptr = PTR(op1);
- /* op2_ptr points to temporary space. */
- res_ptr = PTR(res);
- }
- if (op1_size >= op2_size)
- {
- /* We can just ignore the part of OP1 that stretches above OP2,
- because the result limbs are zero there. */
- /* First loop finds the size of the result. */
- for (i = op2_size - 1; i >= 0; i--)
- if ((~op1_ptr[i] & op2_ptr[i]) != 0)
- break;
- res_size = i + 1;
- count = res_size;
- }
- else
- {
- res_size = op2_size;
- /* Copy the part of OP2 that stretches above OP1, to RES. */
- MPN_COPY (res_ptr + op1_size, op2_ptr + op1_size, op2_size - op1_size);
- count = op1_size;
- }
- if (res_size != 0)
- {
- /* Second loop computes the real result. */
- for (i = count - 1; i >= 0; i--)
- res_ptr[i] = ~op1_ptr[i] & op2_ptr[i];
- cy = mpn_add_1 (res_ptr, res_ptr, res_size, (mp_limb_t) 1);
- if (cy)
- {
- res_ptr[res_size] = cy;
- res_size++;
- }
- }
- else
- {
- res_ptr[0] = 1;
- res_size = 1;
- }
- SIZ(res) = -res_size;
- }
- TMP_FREE;
- }