1 #include "os.h"
2 #include <mp.h>
3 #include "dat.h"
4 
5 #define VLDIGITS (sizeof(vlong)/sizeof(mpdigit))
6 
7 /*
8  *  this code assumes that a vlong is an integral number of
9  *  mpdigits long.
10  */
11 mpint*
12 vtomp(vlong v, mpint *b)
13 {
14 	int s;
15 	uvlong uv;
16 
17 	if(b == nil)
18 		b = mpnew(VLDIGITS*sizeof(mpdigit));
19 	else
20 		mpbits(b, VLDIGITS*sizeof(mpdigit));
21 	mpassign(mpzero, b);
22 	if(v == 0)
23 		return b;
24 	if(v < 0){
25 		b->sign = -1;
26 		uv = -v;
27 	} else
28 		uv = v;
29 	for(s = 0; s < VLDIGITS && uv != 0; s++){
30 		b->p[s] = uv;
31 	/* !@*$&!@$ gcc gives warnings about the >> here
32 	 * when running on 64-bit machines, even though
33 	 * it's in dead code.  fake it out with two shifts.
34 		if(sizeof(mpdigit) == sizeof(uvlong))
35 			uv = 0;
36 		else
37 			uv >>= sizeof(mpdigit)*8;
38 	*/
39 		uv >>= sizeof(mpdigit)*4;
40 		uv >>= sizeof(mpdigit)*4;
41 	}
42 	b->top = s;
43 	return b;
44 }
45 
46 vlong
47 mptov(mpint *b)
48 {
49 	uvlong v;
50 	int s;
51 
52 	if(b->top == 0)
53 		return 0LL;
54 
55 	mpnorm(b);
56 	if(b->top > VLDIGITS){
57 		if(b->sign > 0)
58 			return (vlong)MAXVLONG;
59 		else
60 			return (vlong)MINVLONG;
61 	}
62 
63 	v = 0ULL;
64 	for(s = 0; s < b->top; s++)
65 		v |= b->p[s]<<(s*sizeof(mpdigit)*8);
66 
67 	if(b->sign > 0){
68 		if(v > MAXVLONG)
69 			v = MAXVLONG;
70 	} else {
71 		if(v > MINVLONG)
72 			v = MINVLONG;
73 		else
74 			v = -(vlong)v;
75 	}
76 
77 	return (vlong)v;
78 }