| ---
tnan64.c (1257B)
---
1 /* Copyright (c) 2002-2006 Lucent Technologies; see LICENSE */
2
3 /*
4 * 64-bit IEEE not-a-number routines.
5 * This is big/little-endian portable assuming that
6 * the 64-bit doubles and 64-bit integers have the
7 * same byte ordering.
8 */
9
10 #include "plan9.h"
11 #include
12 #include "fmt.h"
13 #include "fmtdef.h"
14
15 static uvlong uvnan = ((uvlong)0x7FF00000<<32)|0x00000001;
16 static uvlong uvinf = ((uvlong)0x7FF00000<<32)|0x00000000;
17 static uvlong uvneginf = ((uvlong)0xFFF00000<<32)|0x00000000;
18
19 /* gcc sees through the obvious casts. */
20 static uvlong
21 d2u(double d)
22 {
23 union {
24 uvlong v;
25 double d;
26 } u;
27 assert(sizeof(u.d) == sizeof(u.v));
28 u.d = d;
29 return u.v;
30 }
31
32 static double
33 u2d(uvlong v)
34 {
35 union {
36 uvlong v;
37 double d;
38 } u;
39 assert(sizeof(u.d) == sizeof(u.v));
40 u.v = v;
41 return u.d;
42 }
43
44 double
45 __NaN(void)
46 {
47 return u2d(uvnan);
48 }
49
50 int
51 __isNaN(double d)
52 {
53 uvlong x;
54
55 x = d2u(d);
56 /* IEEE 754: exponent bits 0x7FF and non-zero mantissa */
57 return (x&uvinf) == uvinf && (x&~uvneginf) != 0;
58 }
59
60 double
61 __Inf(int sign)
62 {
63 return u2d(sign < 0 ? uvneginf : uvinf);
64 }
65
66 int
67 __isInf(double d, int sign)
68 {
69 uvlong x;
70
71 x = d2u(d);
72 if(sign == 0)
73 return x==uvinf || x==uvneginf;
74 else if(sign > 0)
75 return x==uvinf;
76 else
77 return x==uvneginf;
78 } |