--- /dev/null
+/* mpz_xor -- Logical xor.
+
+Copyright (C) 1991, 1993, 1994, 1996, 1997, 2000 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 2.1 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; see the file COPYING.LIB. If not, write to
+the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+MA 02111-1307, USA. */
+
+#include "gmp.h"
+#include "gmp-impl.h"
+
+void
+#if __STDC__
+mpz_xor (mpz_ptr res, mpz_srcptr op1, mpz_srcptr op2)
+#else
+mpz_xor (res, op1, op2)
+ mpz_ptr res;
+ mpz_srcptr op1;
+ mpz_srcptr op2;
+#endif
+{
+ mp_srcptr op1_ptr, op2_ptr;
+ mp_size_t op1_size, op2_size;
+ mp_ptr res_ptr;
+ mp_size_t res_size, res_alloc;
+ mp_size_t i;
+ TMP_DECL (marker);
+
+ TMP_MARK (marker);
+ op1_size = op1->_mp_size;
+ op2_size = op2->_mp_size;
+
+ op1_ptr = op1->_mp_d;
+ op2_ptr = op2->_mp_d;
+ res_ptr = res->_mp_d;
+
+ if (op1_size >= 0)
+ {
+ if (op2_size >= 0)
+ {
+ if (op1_size >= op2_size)
+ {
+ if (res->_mp_alloc < op1_size)
+ {
+ _mpz_realloc (res, op1_size);
+ op1_ptr = op1->_mp_d;
+ op2_ptr = op2->_mp_d;
+ res_ptr = res->_mp_d;
+ }
+
+ 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 (res->_mp_alloc < op2_size)
+ {
+ _mpz_realloc (res, op2_size);
+ op1_ptr = op1->_mp_d;
+ op2_ptr = op2->_mp_d;
+ res_ptr = res->_mp_d;
+ }
+
+ 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;
+ }
+
+ MPN_NORMALIZE (res_ptr, res_size);
+ res->_mp_size = 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, the result will be positive.
+ (-OP1) ^ (-OP2) =
+ = ~(OP1 - 1) ^ ~(OP2 - 1) =
+ = (OP1 - 1) ^ (OP2 - 1) */
+
+ op1_size = -op1_size;
+ op2_size = -op2_size;
+
+ /* Possible optimization: Decrease mpn_sub precision,
+ as we won't use the entire res of both. */
+ opx = (mp_ptr) TMP_ALLOC (op1_size * BYTES_PER_MP_LIMB);
+ mpn_sub_1 (opx, op1_ptr, op1_size, (mp_limb_t) 1);
+ op1_ptr = opx;
+
+ opx = (mp_ptr) TMP_ALLOC (op2_size * BYTES_PER_MP_LIMB);
+ mpn_sub_1 (opx, op2_ptr, op2_size, (mp_limb_t) 1);
+ op2_ptr = opx;
+
+ res_alloc = MAX (op1_size, op2_size);
+ if (res->_mp_alloc < res_alloc)
+ {
+ _mpz_realloc (res, res_alloc);
+ res_ptr = res->_mp_d;
+ /* Don't re-read OP1_PTR and OP2_PTR. They point to
+ temporary space--never to the space RES->_mp_d used
+ to point to before reallocation. */
+ }
+
+ if (op1_size > op2_size)
+ {
+ 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
+ {
+ 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;
+ }
+
+ MPN_NORMALIZE (res_ptr, res_size);
+ res->_mp_size = res_size;
+ TMP_FREE (marker);
+ 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 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;
+
+ opx = (mp_ptr) TMP_ALLOC (op2_size * BYTES_PER_MP_LIMB);
+ mpn_sub_1 (opx, op2_ptr, op2_size, (mp_limb_t) 1);
+ op2_ptr = opx;
+
+ res_alloc = MAX (op1_size, op2_size) + 1;
+ if (res->_mp_alloc < res_alloc)
+ {
+ _mpz_realloc (res, res_alloc);
+ op1_ptr = op1->_mp_d;
+ res_ptr = res->_mp_d;
+ /* Don't re-read OP2_PTR. It points to temporary space--never
+ to the space RES->_mp_d used to point to before reallocation. */
+ }
+
+ if (op1_size > op2_size)
+ {
+ 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
+ {
+ 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;
+ }
+
+ cy = mpn_add_1 (res_ptr, res_ptr, res_size, (mp_limb_t) 1);
+ if (cy)
+ {
+ res_ptr[res_size] = cy;
+ res_size++;
+ }
+
+ MPN_NORMALIZE (res_ptr, res_size);
+ res->_mp_size = -res_size;
+ TMP_FREE (marker);
+ }
+}
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