1 /* Cray PVP/IEEE mpn_mul_basecase.
2
3 Copyright 2000, 2001 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 either:
9
10 * the GNU Lesser General Public License as published by the Free
11 Software Foundation; either version 3 of the License, or (at your
12 option) any later version.
13
14 or
15
16 * the GNU General Public License as published by the Free Software
17 Foundation; either version 2 of the License, or (at your option) any
18 later version.
19
20 or both in parallel, as here.
21
22 The GNU MP Library is distributed in the hope that it will be useful, but
23 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
24 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
25 for more details.
26
27 You should have received copies of the GNU General Public License and the
28 GNU Lesser General Public License along with the GNU MP Library. If not,
29 see https://www.gnu.org/licenses/. */
30
31 /* The most critical loop of this code runs at about 5 cycles/limb on a T90.
32 That is not perfect, mainly due to vector register shortage. */
33
34 #include <intrinsics.h>
35 #include "gmp-impl.h"
36
37 void
mpn_mul_basecase(mp_ptr rp,mp_srcptr up,mp_size_t un,mp_srcptr vp,mp_size_t vn)38 mpn_mul_basecase (mp_ptr rp,
39 mp_srcptr up, mp_size_t un,
40 mp_srcptr vp, mp_size_t vn)
41 {
42 mp_limb_t cy[un + vn];
43 mp_limb_t vl;
44 mp_limb_t a, b, r, s0, s1, c0, c1;
45 mp_size_t i, j;
46 int more_carries;
47
48 for (i = 0; i < un + vn; i++)
49 {
50 rp[i] = 0;
51 cy[i] = 0;
52 }
53
54 #pragma _CRI novector
55 for (j = 0; j < vn; j++)
56 {
57 vl = vp[j];
58
59 a = up[0] * vl;
60 r = rp[j];
61 s0 = a + r;
62 rp[j] = s0;
63 c0 = ((a & r) | ((a | r) & ~s0)) >> 63;
64 cy[j] += c0;
65
66 #pragma _CRI ivdep
67 for (i = 1; i < un; i++)
68 {
69 a = up[i] * vl;
70 b = _int_mult_upper (up[i - 1], vl);
71 s0 = a + b;
72 c0 = ((a & b) | ((a | b) & ~s0)) >> 63;
73 r = rp[j + i];
74 s1 = s0 + r;
75 rp[j + i] = s1;
76 c1 = ((s0 & r) | ((s0 | r) & ~s1)) >> 63;
77 cy[j + i] += c0 + c1;
78 }
79 rp[j + un] = _int_mult_upper (up[un - 1], vl);
80 }
81
82 more_carries = 0;
83 #pragma _CRI ivdep
84 for (i = 1; i < un + vn; i++)
85 {
86 r = rp[i];
87 c0 = cy[i - 1];
88 s0 = r + c0;
89 rp[i] = s0;
90 c0 = (r & ~s0) >> 63;
91 more_carries += c0;
92 }
93 /* If that second loop generated carry, handle that in scalar loop. */
94 if (more_carries)
95 {
96 mp_limb_t cyrec = 0;
97 for (i = 1; i < un + vn; i++)
98 {
99 r = rp[i];
100 c0 = (r < cy[i - 1]);
101 s0 = r + cyrec;
102 rp[i] = s0;
103 c1 = (r & ~s0) >> 63;
104 cyrec = c0 | c1;
105 }
106 }
107 }
108