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/*
* 64-bit IEEE not-a-number routines.
* This is big/little-endian portable assuming that
* the 64-bit doubles and 64-bit integers have the
* same byte ordering.
*/
#include "plan9.h"
#include "fmt.h"
#include "fmtdef.h"
static uvlong uvnan = ((uvlong)0x7FF00000<<32)|0x00000001;
static uvlong uvinf = ((uvlong)0x7FF00000<<32)|0x00000000;
static uvlong uvneginf = ((uvlong)0xFFF00000<<32)|0x00000000;
double
__NaN(void)
{
uvlong *p;
/* gcc complains about "return *(double*)&uvnan;" */
p = &uvnan;
return *(double*)p;
}
int
__isNaN(double d)
{
/*
* Used to just say x = *(uvlong*)&d,
* but gcc miscompiles that!
*/
union {
uvlong i;
double f;
} u;
uvlong x;
u.f = d;
x = u.i;
/* IEEE 754: exponent bits 0x7FF and non-zero mantissa */
return (x&uvinf) == uvinf && (x&~uvneginf) != 0;
}
double
__Inf(int sign)
{
uvlong *p;
if(sign < 0)
p = &uvinf;
else
p = &uvneginf;
return *(double*)p;
}
int
__isInf(double d, int sign)
{
uvlong x;
double *p;
p = &d;
x = *(uvlong*)p;
if(sign == 0)
return x==uvinf || x==uvneginf;
else if(sign > 0)
return x==uvinf;
else
return x==uvneginf;
}
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