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
|
#include "pdefs.h"
#include "precision.h"
#include <string.h>
#ifdef ASM_16BIT
#include "asm16bit.h"
#endif
/*
* Add
*
* This will work correctly if -0 is passed as input
*/
precision padd(u, v)
register precision v;
#ifndef ASM_16BIT
precision u;
{
register digitPtr wPtr, uPtr, vPtr;
#else
register precision u;
{
register digitPtr wPtr;
digitPtr uPtr;
#endif
precision w; /* function result */
register accumulator temp; /* 0 <= temp < 2*base */
register digit carry; /* 0 <= carry <= 1 */
#ifdef ASM_16BIT
register int size;
#endif
(void) pparm(u);
(void) pparm(v);
if (u->sign != v->sign) { /* Are we are actually subtracting? */
w = pUndef;
if (v->sign) {
v->sign = !v->sign; /* can't generate -0 */
pset(&w, psub(u, v));
v->sign = !v->sign;
} else {
u->sign = !u->sign; /* can't generate -0 */
pset(&w, psub(v, u));
u->sign = !u->sign;
}
} else {
if (u->size < v->size) { /* u is always biggest number */
w = u; u = v; v = w;
}
w = palloc(u->size+1); /* there is at most one added digit */
if (w == pUndef) return w; /* arguments not destroyed */
w->sign = u->sign;
uPtr = u->value;
wPtr = w->value;
#ifndef ASM_16BIT
vPtr = v->value;
carry = 0;
do { /* Add digits in both args */
temp = *uPtr++ + *vPtr++; /* 0 <= temp < 2*base-1 */
temp += carry; /* 0 <= temp < 2*base */
carry = divBase(temp); /* 0 <= carry <= 1 */
*wPtr++ = modBase(temp); /* mod has positive args */
} while (vPtr < v->value + v->size);
while (uPtr < u->value + u->size) { /* propogate carry */
temp = *uPtr++ + carry;
carry = divBase(temp);
*wPtr++ = modBase(temp);
}
*wPtr = carry;
#else
size = v->size;
temp = u->size - size;
carry = memaddw(wPtr, uPtr, v->value, size);
if (temp > 0) {
memcpy(wPtr + size, uPtr + size, temp * sizeof(digit));
if (carry) {
carry = memincw(wPtr + size, temp);
}
}
wPtr[u->size] = carry; /* yes, I do mean u->size */
#endif
if (carry == 0) {
--(w->size);
}
}
pdestroy(u);
pdestroy(v);
return presult(w);
}
|
