commit - ada24b4005504a9cc8035987cf5175940ae568a7
commit + 66f6e2b651124387f83b9af17104a79d6d93f67b
blob - 7d71915747724c7a40bc8274874a1b26fb1307fd
blob + 9c0cc7bfdaf5d13651d962c8a646f13eb7508415
--- src/lib9/fmt/nan64.c
+++ src/lib9/fmt/nan64.c
*/
#include "plan9.h"
+#include <assert.h>
#include "fmt.h"
#include "fmtdef.h"
static uvlong uvinf = ((uvlong)0x7FF00000<<32)|0x00000000;
static uvlong uvneginf = ((uvlong)0xFFF00000<<32)|0x00000000;
+/* gcc sees through the obvious casts. */
+static uvlong
+d2u(double d)
+{
+ union {
+ uvlong v;
+ double d;
+ } u;
+ assert(sizeof(u.d) == sizeof(u.v));
+ u.d = d;
+ return u.v;
+}
+
+static double
+u2d(uvlong v)
+{
+ union {
+ uvlong v;
+ double d;
+ } u;
+ assert(sizeof(u.d) == sizeof(u.v));
+ u.v = v;
+ return u.d;
+}
+
double
__NaN(void)
{
- uvlong *p;
-
- /* gcc complains about "return *(double*)&uvnan;" */
- p = &uvnan;
- return *(double*)p;
+ return u2d(uvnan);
}
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;
+ x = d2u(d);
/* 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;
+ return u2d(sign < 0 ? uvneginf : uvinf);
}
int
__isInf(double d, int sign)
{
uvlong x;
- double *p;
-
- p = &d;
- x = *(uvlong*)p;
+
+ x = d2u(d);
if(sign == 0)
return x==uvinf || x==uvneginf;
else if(sign > 0)