tmptouv.c - plan9port - [fork] Plan 9 from user space
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tmptouv.c (991B)
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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 uvtomp(uvlong v, mpint *b)
13 {
14 int s;
15
16 if(b == nil)
17 b = mpnew(VLDIGITS*sizeof(mpdigit));
18 else
19 mpbits(b, VLDIGITS*sizeof(mpdigit));
20 mpassign(mpzero, b);
21 if(v == 0)
22 return b;
23 for(s = 0; s < VLDIGITS && v != 0; s++){
24 b->p[s] = v;
25 /* !@*$&!@$ gcc gives warnings about the >> here
26 * when running on 64-bit machines, even though
27 * it's in dead code. fake it out with two shifts.
28 if(sizeof(mpdigit) == sizeof(uvlong))
29 v = 0;
30 else
31 v >>= sizeof(mpdigit)*8;
32 */
33 v >>= sizeof(mpdigit)*4;
34 v >>= sizeof(mpdigit)*4;
35 }
36 b->top = s;
37 return b;
38 }
39
40 uvlong
41 mptouv(mpint *b)
42 {
43 uvlong v;
44 int s;
45
46 if(b->top == 0)
47 return 0LL;
48
49 mpnorm(b);
50 if(b->top > VLDIGITS)
51 return MAXVLONG;
52
53 v = 0ULL;
54 for(s = 0; s < b->top; s++)
55 v |= (uvlong)b->p[s]<<(s*sizeof(mpdigit)*8);
56
57 return v;
58 }