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
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
|
/* See LICENSE file for copyright and license details. */
#include "internals.h"
#if defined(__x86_64__) && !defined(ZAHL_NO_ASM)
# define ASM3(code) \
__asm__ __volatile__ (code : [x]"+r"(carry), [a]"+r"(ac), [b]"+r"(bc), [c]"+r"(cc))
# define ASM2(code) \
__asm__ __volatile__ (code : [x]"+r"(carry), [a]"+r"(ac), [b]"+r"(bc))
# define ADD2(off) \
"\n movq "#off"(%[b]), %[x]" \
"\n adcq %[x], "#off"(%[a])"
# define ADD3(off) \
"\n movq "#off"(%[b]), %[x]" \
"\n adcq "#off"(%[c]), %[x]" \
"\n movq %[x], "#off"(%[a])"
# define WRAP_CARRY(interior) \
"\n addq $-1, %[x]" \
interior \
"\n movq $1, %[x]" \
"\n jc 1f" \
"\n movq $0, %[x]" \
"\n 1:"
/*
* I have already tried setc, cmovnc, cmovc, and adc,
* instead of the last four lines. There does not seem
* to be any better why to store the carry flag.
*/
# define ASM_ADD(N) \
do { \
register zahl_char_t carry = 0; \
size_t i; \
for (i = 0; (INC(4)), (i += 4) <= n;) \
ASM##N(WRAP_CARRY(ADD##N(-32) ADD##N(-24) ADD##N(-16) ADD##N(-8))); \
switch (n & 3) { \
case 3: \
ASM##N(WRAP_CARRY(ADD##N(-32) ADD##N(-24) ADD##N(-16))); \
break; \
case 2: \
ASM##N(WRAP_CARRY(ADD##N(-32) ADD##N(-24))); \
break; \
case 1: \
ASM##N(WRAP_CARRY(ADD##N(-32))); \
break; \
default: \
break; \
} \
i = n; \
while (carry) { \
carry = libzahl_add_overflow(a->chars + i, a->chars[i], 1); \
i++; \
} \
if (a->used < i) \
a->used = i; \
} while (0)
#endif
static inline void
zadd_impl_4(z_t a, z_t b, z_t c, size_t n)
{
#ifdef ASM_ADD
register zahl_char_t *ac = a->chars, *bc = b->chars, *cc = c->chars;
# define INC(P) (ac += (P), bc += (P), cc += (P))
ASM_ADD(3);
# undef INC
#else
zahl_char_t carry = 0, tcarry;
zahl_char_t *ac = a->chars, *bc = b->chars, *cc = c->chars;
size_t i;
for (i = 0; i < n; i++) {
tcarry = libzahl_add_overflow(ac + i, bc[i], cc[i]);
carry = tcarry | (zahl_char_t)libzahl_add_overflow(ac + i, ac[i], carry);
}
while (carry) {
carry = libzahl_add_overflow(ac + i, ac[i], 1);
i++;
}
if (a->used < i)
a->used = i;
#endif
}
static inline void
zadd_impl_3(z_t a, z_t b, size_t n)
{
#ifdef ASM_ADD
register zahl_char_t *ac = a->chars, *bc = b->chars;
# define INC(P) (ac += (P), bc += (P))
ASM_ADD(2);
# undef INC
#else
zadd_impl_4(a, a, b, n);
#endif
}
static inline void
libzahl_zadd_unsigned(z_t a, z_t b, z_t c)
{
size_t size, n;
if (unlikely(zzero(b))) {
zabs(a, c);
return;
} else if (unlikely(zzero(c))) {
zabs(a, b);
return;
}
size = MAX(b->used, c->used);
n = b->used + c->used - size;
ENSURE_SIZE(a, size + 1);
a->chars[size] = 0;
if (a == b) {
if (a->used < c->used) {
n = c->used;
zmemset(a->chars + a->used, 0, n - a->used);
}
zadd_impl_3(a, c, n);
} else if (unlikely(a == c)) {
if (a->used < b->used) {
n = b->used;
zmemset(a->chars + a->used, 0, n - a->used);
}
zadd_impl_3(a, b, n);
} else if (likely(b->used > c->used)) {
zmemcpy(a->chars + n, b->chars + n, size - n);
a->used = size;
zadd_impl_4(a, b, c, n);
} else {
zmemcpy(a->chars + n, c->chars + n, size - n);
a->used = size;
zadd_impl_4(a, b, c, n);
}
SET_SIGNUM(a, 1);
}
void
zadd_unsigned(z_t a, z_t b, z_t c)
{
libzahl_zadd_unsigned(a, b, c);
}
void
zadd_unsigned_assign(z_t a, z_t b)
{
size_t size, n;
if (unlikely(zzero(a))) {
zabs(a, b);
return;
} else if (unlikely(zzero(b))) {
return;
}
size = MAX(a->used, b->used);
n = a->used + b->used - size;
ENSURE_SIZE(a, size + 1);
a->chars[size] = 0;
if (a->used < b->used) {
n = b->used;
zmemset(a->chars + a->used, 0, n - a->used);
}
zadd_impl_3(a, b, n);
SET_SIGNUM(a, 1);
}
void
zadd(z_t a, z_t b, z_t c)
{
if (unlikely(zzero(b))) {
SET(a, c);
} else if (unlikely(zzero(c))) {
SET(a, b);
} else if (unlikely(znegative(b))) {
if (znegative(c)) {
libzahl_zadd_unsigned(a, b, c);
SET_SIGNUM(a, -zsignum(a));
} else {
zsub_unsigned(a, c, b);
}
} else if (unlikely(znegative(c))) {
zsub_unsigned(a, b, c);
} else {
libzahl_zadd_unsigned(a, b, c);
}
}
|
