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
|
/* { dg-require-effective-target int32plus } */
typedef long unsigned int size_t;
extern void *memset (void *__s, int __c, size_t __n) __attribute__ ((__nothrow__)) __attribute__ ((__nonnull__ (1)));
static void
encode (words, low, hi)
long *words;
unsigned long low;
long hi;
{
words[0] = ((low) & (((unsigned long) 1 << (sizeof(unsigned long) / 2)) - 1));
words[1] = ((unsigned long) (low) >> sizeof(unsigned long) / 2);
words[2] = ((hi) & (((unsigned long) 1 << (sizeof(unsigned long) / 2)) - 1));
words[3] = ((unsigned long) (hi) >> sizeof(unsigned long) / 2);
}
static void
decode (words, low, hi)
long *words;
unsigned long *low;
long *hi;
{
*low = words[0] + words[1] * ((unsigned long) 1 << sizeof(unsigned long) / 2);
*hi = words[2] + words[3] * ((unsigned long) 1 << sizeof(unsigned long) / 2);
}
int
neg_double (l1, h1, lv, hv)
unsigned long l1;
long h1;
unsigned long *lv;
long *hv;
{
if (l1 == 0)
{
*lv = 0;
*hv = - h1;
return (*hv & h1) < 0;
}
else
{
*lv = -l1;
*hv = ~h1;
return 0;
}
}
int
add_double (l1, h1, l2, h2, lv, hv)
unsigned long l1, l2;
long h1, h2;
unsigned long *lv;
long *hv;
{
unsigned long l;
long h;
l = l1 + l2;
h = h1 + h2 + (l < l1);
*lv = l;
*hv = h;
return ((~((h1) ^ (h2)) & ((h1) ^ (h))) < 0);
}
int
mul_double (l1, h1, l2, h2, lv, hv)
unsigned long l1, l2;
long h1, h2;
unsigned long *lv;
long *hv;
{
long arg1[4];
long arg2[4];
long prod[4 * 2];
unsigned long carry;
int i, j, k;
unsigned long toplow, neglow;
long tophigh, neghigh;
encode (arg1, l1, h1);
encode (arg2, l2, h2);
memset ((char *) prod, 0, sizeof prod);
for (i = 0; i < 4; i++)
{
carry = 0;
for (j = 0; j < 4; j++)
{
k = i + j;
carry += arg1[i] * arg2[j];
carry += prod[k];
prod[k] = ((carry) & (((unsigned long) 1 << (sizeof(unsigned long) / 2)) - 1));
carry = ((unsigned long) (carry) >> sizeof(unsigned long) / 2);
}
prod[i + 4] = carry;
}
decode (prod, lv, hv);
decode (prod + 4, &toplow, &tophigh);
if (h1 < 0)
{
neg_double (l2, h2, &neglow, &neghigh);
add_double (neglow, neghigh, toplow, tophigh, &toplow, &tophigh);
}
if (h2 < 0)
{
neg_double (l1, h1, &neglow, &neghigh);
add_double (neglow, neghigh, toplow, tophigh, &toplow, &tophigh);
}
return (*hv < 0 ? ~(toplow & tophigh) : toplow | tophigh) != 0;
}
|
