mul_basecase.c
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上传日期:2022-08-06
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- /* Cray PVP/IEEE mpn_mul_basecase.
- Copyright 2000, 2001 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/. */
- /* The most critical loop of this code runs at about 5 cycles/limb on a T90.
- That is not perfect, mainly due to vector register shortage. */
- #include <intrinsics.h>
- #include "gmp.h"
- #include "gmp-impl.h"
- void
- mpn_mul_basecase (mp_ptr rp,
- mp_srcptr up, mp_size_t un,
- mp_srcptr vp, mp_size_t vn)
- {
- mp_limb_t cy[un + vn];
- mp_limb_t vl;
- mp_limb_t a, b, r, s0, s1, c0, c1;
- mp_size_t i, j;
- int more_carries;
- for (i = 0; i < un + vn; i++)
- {
- rp[i] = 0;
- cy[i] = 0;
- }
- #pragma _CRI novector
- for (j = 0; j < vn; j++)
- {
- vl = vp[j];
- a = up[0] * vl;
- r = rp[j];
- s0 = a + r;
- rp[j] = s0;
- c0 = ((a & r) | ((a | r) & ~s0)) >> 63;
- cy[j] += c0;
- #pragma _CRI ivdep
- for (i = 1; i < un; i++)
- {
- a = up[i] * vl;
- b = _int_mult_upper (up[i - 1], vl);
- s0 = a + b;
- c0 = ((a & b) | ((a | b) & ~s0)) >> 63;
- r = rp[j + i];
- s1 = s0 + r;
- rp[j + i] = s1;
- c1 = ((s0 & r) | ((s0 | r) & ~s1)) >> 63;
- cy[j + i] += c0 + c1;
- }
- rp[j + un] = _int_mult_upper (up[un - 1], vl);
- }
- more_carries = 0;
- #pragma _CRI ivdep
- for (i = 1; i < un + vn; i++)
- {
- r = rp[i];
- c0 = cy[i - 1];
- s0 = r + c0;
- rp[i] = s0;
- c0 = (r & ~s0) >> 63;
- more_carries += c0;
- }
- /* If that second loop generated carry, handle that in scalar loop. */
- if (more_carries)
- {
- mp_limb_t cyrec = 0;
- for (i = 1; i < un + vn; i++)
- {
- r = rp[i];
- c0 = (r < cy[i - 1]);
- s0 = r + cyrec;
- rp[i] = s0;
- c1 = (r & ~s0) >> 63;
- cyrec = c0 | c1;
- }
- }
- }