Annotation of OpenXM_contrib/gmp/mpz/and.c, Revision 1.1
1.1 ! maekawa 1: /* mpz_and -- Logical and.
! 2:
! 3: Copyright (C) 1991, 1993, 1994, 1996 Free Software Foundation, Inc.
! 4:
! 5: This file is part of the GNU MP Library.
! 6:
! 7: The GNU MP Library is free software; you can redistribute it and/or modify
! 8: it under the terms of the GNU Library General Public License as published by
! 9: the Free Software Foundation; either version 2 of the License, or (at your
! 10: option) any later version.
! 11:
! 12: The GNU MP Library is distributed in the hope that it will be useful, but
! 13: WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
! 14: or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public
! 15: License for more details.
! 16:
! 17: You should have received a copy of the GNU Library General Public License
! 18: along with the GNU MP Library; see the file COPYING.LIB. If not, write to
! 19: the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
! 20: MA 02111-1307, USA. */
! 21:
! 22: #include "gmp.h"
! 23: #include "gmp-impl.h"
! 24:
! 25: void
! 26: #if __STDC__
! 27: mpz_and (mpz_ptr res, mpz_srcptr op1, mpz_srcptr op2)
! 28: #else
! 29: mpz_and (res, op1, op2)
! 30: mpz_ptr res;
! 31: mpz_srcptr op1;
! 32: mpz_srcptr op2;
! 33: #endif
! 34: {
! 35: mp_srcptr op1_ptr, op2_ptr;
! 36: mp_size_t op1_size, op2_size;
! 37: mp_ptr res_ptr;
! 38: mp_size_t res_size;
! 39: mp_size_t i;
! 40: TMP_DECL (marker);
! 41:
! 42: TMP_MARK (marker);
! 43: op1_size = op1->_mp_size;
! 44: op2_size = op2->_mp_size;
! 45:
! 46: op1_ptr = op1->_mp_d;
! 47: op2_ptr = op2->_mp_d;
! 48: res_ptr = res->_mp_d;
! 49:
! 50: if (op1_size >= 0)
! 51: {
! 52: if (op2_size >= 0)
! 53: {
! 54: res_size = MIN (op1_size, op2_size);
! 55: /* First loop finds the size of the result. */
! 56: for (i = res_size - 1; i >= 0; i--)
! 57: if ((op1_ptr[i] & op2_ptr[i]) != 0)
! 58: break;
! 59: res_size = i + 1;
! 60:
! 61: /* Handle allocation, now then we know exactly how much space is
! 62: needed for the result. */
! 63: if (res->_mp_alloc < res_size)
! 64: {
! 65: _mpz_realloc (res, res_size);
! 66: op1_ptr = op1->_mp_d;
! 67: op2_ptr = op2->_mp_d;
! 68: res_ptr = res->_mp_d;
! 69: }
! 70:
! 71: /* Second loop computes the real result. */
! 72: for (i = res_size - 1; i >= 0; i--)
! 73: res_ptr[i] = op1_ptr[i] & op2_ptr[i];
! 74:
! 75: res->_mp_size = res_size;
! 76: return;
! 77: }
! 78: else /* op2_size < 0 */
! 79: {
! 80: /* Fall through to the code at the end of the function. */
! 81: }
! 82: }
! 83: else
! 84: {
! 85: if (op2_size < 0)
! 86: {
! 87: mp_ptr opx;
! 88: mp_limb_t cy;
! 89: mp_size_t res_alloc;
! 90:
! 91: /* Both operands are negative, so will be the result.
! 92: -((-OP1) & (-OP2)) = -(~(OP1 - 1) & ~(OP2 - 1)) =
! 93: = ~(~(OP1 - 1) & ~(OP2 - 1)) + 1 =
! 94: = ((OP1 - 1) | (OP2 - 1)) + 1 */
! 95:
! 96: /* It might seem as we could end up with an (invalid) result with
! 97: a leading zero-limb here when one of the operands is of the
! 98: type 1,,0,,..,,.0. But some analysis shows that we surely
! 99: would get carry into the zero-limb in this situation... */
! 100:
! 101: op1_size = -op1_size;
! 102: op2_size = -op2_size;
! 103:
! 104: res_alloc = 1 + MAX (op1_size, op2_size);
! 105:
! 106: opx = (mp_ptr) TMP_ALLOC (op1_size * BYTES_PER_MP_LIMB);
! 107: mpn_sub_1 (opx, op1_ptr, op1_size, (mp_limb_t) 1);
! 108: op1_ptr = opx;
! 109:
! 110: opx = (mp_ptr) TMP_ALLOC (op2_size * BYTES_PER_MP_LIMB);
! 111: mpn_sub_1 (opx, op2_ptr, op2_size, (mp_limb_t) 1);
! 112: op2_ptr = opx;
! 113:
! 114: if (res->_mp_alloc < res_alloc)
! 115: {
! 116: _mpz_realloc (res, res_alloc);
! 117: res_ptr = res->_mp_d;
! 118: /* Don't re-read OP1_PTR and OP2_PTR. They point to
! 119: temporary space--never to the space RES->_mp_D used
! 120: to point to before reallocation. */
! 121: }
! 122:
! 123: if (op1_size >= op2_size)
! 124: {
! 125: MPN_COPY (res_ptr + op2_size, op1_ptr + op2_size,
! 126: op1_size - op2_size);
! 127: for (i = op2_size - 1; i >= 0; i--)
! 128: res_ptr[i] = op1_ptr[i] | op2_ptr[i];
! 129: res_size = op1_size;
! 130: }
! 131: else
! 132: {
! 133: MPN_COPY (res_ptr + op1_size, op2_ptr + op1_size,
! 134: op2_size - op1_size);
! 135: for (i = op1_size - 1; i >= 0; i--)
! 136: res_ptr[i] = op1_ptr[i] | op2_ptr[i];
! 137: res_size = op2_size;
! 138: }
! 139:
! 140: cy = mpn_add_1 (res_ptr, res_ptr, res_size, (mp_limb_t) 1);
! 141: if (cy)
! 142: {
! 143: res_ptr[res_size] = cy;
! 144: res_size++;
! 145: }
! 146:
! 147: res->_mp_size = -res_size;
! 148: TMP_FREE (marker);
! 149: return;
! 150: }
! 151: else
! 152: {
! 153: /* We should compute -OP1 & OP2. Swap OP1 and OP2 and fall
! 154: through to the code that handles OP1 & -OP2. */
! 155: {mpz_srcptr t = op1; op1 = op2; op2 = t;}
! 156: {mp_srcptr t = op1_ptr; op1_ptr = op2_ptr; op2_ptr = t;}
! 157: {mp_size_t t = op1_size; op1_size = op2_size; op2_size = t;}
! 158: }
! 159:
! 160: }
! 161:
! 162: {
! 163: #if ANDNEW
! 164: mp_size_t op2_lim;
! 165: mp_size_t count;
! 166:
! 167: /* OP2 must be negated as with infinite precision.
! 168:
! 169: Scan from the low end for a non-zero limb. The first non-zero
! 170: limb is simply negated (two's complement). Any subsequent
! 171: limbs are one's complemented. Of course, we don't need to
! 172: handle more limbs than there are limbs in the other, positive
! 173: operand as the result for those limbs is going to become zero
! 174: anyway. */
! 175:
! 176: /* Scan for the least significant. non-zero OP2 limb, and zero the
! 177: result meanwhile for those limb positions. (We will surely
! 178: find a non-zero limb, so we can write the loop with one
! 179: termination condition only.) */
! 180: for (i = 0; op2_ptr[i] == 0; i++)
! 181: res_ptr[i] = 0;
! 182: op2_lim = i;
! 183:
! 184: op2_size = -op2_size;
! 185:
! 186: if (op1_size <= op2_size)
! 187: {
! 188: /* The ones-extended OP2 is >= than the zero-extended OP1.
! 189: RES_SIZE <= OP1_SIZE. Find the exact size. */
! 190: for (i = op1_size - 1; i > op2_lim; i--)
! 191: if ((op1_ptr[i] & ~op2_ptr[i]) != 0)
! 192: break;
! 193: res_size = i + 1;
! 194: for (i = res_size - 1; i > op2_lim; i--)
! 195: res_ptr[i] = op1_ptr[i] & ~op2_ptr[i];
! 196: res_ptr[op2_lim] = op1_ptr[op2_lim] & -op2_ptr[op2_lim];
! 197: /* Yes, this *can* happen! */
! 198: MPN_NORMALIZE (res_ptr, res_size);
! 199: }
! 200: else
! 201: {
! 202: /* The ones-extended OP2 is < than the zero-extended OP1.
! 203: RES_SIZE == OP1_SIZE, since OP1 is normalized. */
! 204: res_size = op1_size;
! 205: MPN_COPY (res_ptr + op2_size, op1_ptr + op2_size, op1_size - op2_size);
! 206: for (i = op2_size - 1; i > op2_lim; i--)
! 207: res_ptr[i] = op1_ptr[i] & ~op2_ptr[i];
! 208: res_ptr[op2_lim] = op1_ptr[op2_lim] & -op2_ptr[op2_lim];
! 209: }
! 210:
! 211: res->_mp_size = res_size;
! 212: #else
! 213:
! 214: /* OP1 is positive and zero-extended,
! 215: OP2 is negative and ones-extended.
! 216: The result will be positive.
! 217: OP1 & -OP2 = OP1 & ~(OP2 - 1). */
! 218:
! 219: mp_ptr opx;
! 220:
! 221: op2_size = -op2_size;
! 222: opx = (mp_ptr) TMP_ALLOC (op2_size * BYTES_PER_MP_LIMB);
! 223: mpn_sub_1 (opx, op2_ptr, op2_size, (mp_limb_t) 1);
! 224: op2_ptr = opx;
! 225:
! 226: if (op1_size > op2_size)
! 227: {
! 228: /* The result has the same size as OP1, since OP1 is normalized
! 229: and longer than the ones-extended OP2. */
! 230: res_size = op1_size;
! 231:
! 232: /* Handle allocation, now then we know exactly how much space is
! 233: needed for the result. */
! 234: if (res->_mp_alloc < res_size)
! 235: {
! 236: _mpz_realloc (res, res_size);
! 237: res_ptr = res->_mp_d;
! 238: op1_ptr = op1->_mp_d;
! 239: /* Don't re-read OP2_PTR. It points to temporary space--never
! 240: to the space RES->_mp_D used to point to before reallocation. */
! 241: }
! 242:
! 243: MPN_COPY (res_ptr + op2_size, op1_ptr + op2_size,
! 244: res_size - op2_size);
! 245: for (i = op2_size - 1; i >= 0; i--)
! 246: res_ptr[i] = op1_ptr[i] & ~op2_ptr[i];
! 247:
! 248: res->_mp_size = res_size;
! 249: }
! 250: else
! 251: {
! 252: /* Find out the exact result size. Ignore the high limbs of OP2,
! 253: OP1 is zero-extended and would make the result zero. */
! 254: for (i = op1_size - 1; i >= 0; i--)
! 255: if ((op1_ptr[i] & ~op2_ptr[i]) != 0)
! 256: break;
! 257: res_size = i + 1;
! 258:
! 259: /* Handle allocation, now then we know exactly how much space is
! 260: needed for the result. */
! 261: if (res->_mp_alloc < res_size)
! 262: {
! 263: _mpz_realloc (res, res_size);
! 264: res_ptr = res->_mp_d;
! 265: op1_ptr = op1->_mp_d;
! 266: /* Don't re-read OP2_PTR. It points to temporary space--never
! 267: to the space RES->_mp_D used to point to before reallocation. */
! 268: }
! 269:
! 270: for (i = res_size - 1; i >= 0; i--)
! 271: res_ptr[i] = op1_ptr[i] & ~op2_ptr[i];
! 272:
! 273: res->_mp_size = res_size;
! 274: }
! 275: #endif
! 276: }
! 277: TMP_FREE (marker);
! 278: }
FreeBSD-CVSweb <freebsd-cvsweb@FreeBSD.org>
![[BACK]](/icons/cvsweb/back.gif){kind=icon}
Return to and.c CVS log ![[TXT]](/icons/cvsweb/text.gif){kind=icon}
![[DIR]](/icons/cvsweb/dir.gif){kind=icon}
Up to [local] / OpenXM_contrib / gmp / mpz