1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
|
/* Alternate implementations of binvert_limb to compare speeds. */
/*
Copyright 2000, 2002 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 either:
* 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.
or
* the GNU General Public License as published by the Free Software
Foundation; either version 2 of the License, or (at your option) any
later version.
or both in parallel, as here.
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 General Public License
for more details.
You should have received copies of the GNU General Public License and the
GNU Lesser General Public License along with the GNU MP Library. If not,
see https://www.gnu.org/licenses/. */
#include <stdio.h>
#include "gmp-impl.h"
#include "longlong.h"
#include "speed.h"
/* Like the standard version in gmp-impl.h, but with the expressions using a
"1-" form. This has the same number of steps, but "1-" is on the
dependent chain, whereas the "2*" in the standard version isn't.
Depending on the CPU this should be the same or a touch slower. */
#if GMP_LIMB_BITS <= 32
#define binvert_limb_mul1(inv,n) \
do { \
mp_limb_t __n = (n); \
mp_limb_t __inv; \
ASSERT ((__n & 1) == 1); \
__inv = binvert_limb_table[(__n&0xFF)/2]; /* 8 */ \
__inv = (1 - __n * __inv) * __inv + __inv; /* 16 */ \
__inv = (1 - __n * __inv) * __inv + __inv; /* 32 */ \
ASSERT (__inv * __n == 1); \
(inv) = __inv; \
} while (0)
#endif
#if GMP_LIMB_BITS > 32 && GMP_LIMB_BITS <= 64
#define binvert_limb_mul1(inv,n) \
do { \
mp_limb_t __n = (n); \
mp_limb_t __inv; \
ASSERT ((__n & 1) == 1); \
__inv = binvert_limb_table[(__n&0xFF)/2]; /* 8 */ \
__inv = (1 - __n * __inv) * __inv + __inv; /* 16 */ \
__inv = (1 - __n * __inv) * __inv + __inv; /* 32 */ \
__inv = (1 - __n * __inv) * __inv + __inv; /* 64 */ \
ASSERT (__inv * __n == 1); \
(inv) = __inv; \
} while (0)
#endif
/* The loop based version used in GMP 3.0 and earlier. Usually slower than
multiplying, due to the number of steps that must be performed. Much
slower when the processor has a good multiply. */
#define binvert_limb_loop(inv,n) \
do { \
mp_limb_t __v = (n); \
mp_limb_t __v_orig = __v; \
mp_limb_t __make_zero = 1; \
mp_limb_t __two_i = 1; \
mp_limb_t __v_inv = 0; \
\
ASSERT ((__v & 1) == 1); \
\
do \
{ \
while ((__two_i & __make_zero) == 0) \
__two_i <<= 1, __v <<= 1; \
__v_inv += __two_i; \
__make_zero -= __v; \
} \
while (__make_zero); \
\
ASSERT (__v_orig * __v_inv == 1); \
(inv) = __v_inv; \
} while (0)
/* Another loop based version with conditionals, but doing a fixed number of
steps. */
#define binvert_limb_cond(inv,n) \
do { \
mp_limb_t __n = (n); \
mp_limb_t __rem = (1 - __n) >> 1; \
mp_limb_t __inv = GMP_LIMB_HIGHBIT; \
int __count; \
\
ASSERT ((__n & 1) == 1); \
\
__count = GMP_LIMB_BITS-1; \
do \
{ \
__inv >>= 1; \
if (__rem & 1) \
{ \
__inv |= GMP_LIMB_HIGHBIT; \
__rem -= __n; \
} \
__rem >>= 1; \
} \
while (-- __count); \
\
ASSERT (__inv * __n == 1); \
(inv) = __inv; \
} while (0)
/* Another loop based bitwise version, but purely arithmetic, no
conditionals. */
#define binvert_limb_arith(inv,n) \
do { \
mp_limb_t __n = (n); \
mp_limb_t __rem = (1 - __n) >> 1; \
mp_limb_t __inv = GMP_LIMB_HIGHBIT; \
mp_limb_t __lowbit; \
int __count; \
\
ASSERT ((__n & 1) == 1); \
\
__count = GMP_LIMB_BITS-1; \
do \
{ \
__lowbit = __rem & 1; \
__inv = (__inv >> 1) | (__lowbit << (GMP_LIMB_BITS-1)); \
__rem = (__rem - (__n & -__lowbit)) >> 1; \
} \
while (-- __count); \
\
ASSERT (__inv * __n == 1); \
(inv) = __inv; \
} while (0)
double
speed_binvert_limb_mul1 (struct speed_params *s)
{
SPEED_ROUTINE_MODLIMB_INVERT (binvert_limb_mul1);
}
double
speed_binvert_limb_loop (struct speed_params *s)
{
SPEED_ROUTINE_MODLIMB_INVERT (binvert_limb_loop);
}
double
speed_binvert_limb_cond (struct speed_params *s)
{
SPEED_ROUTINE_MODLIMB_INVERT (binvert_limb_cond);
}
double
speed_binvert_limb_arith (struct speed_params *s)
{
SPEED_ROUTINE_MODLIMB_INVERT (binvert_limb_arith);
}
|
