xref: /freebsd/lib/libc/amd64/gen/flt_rounds.c (revision dd41de95a84d979615a2ef11df6850622bf6184e)
1 /*
2  * Written by J.T. Conklin, Apr 10, 1995
3  * Public domain.
4  */
5 
6 #include <sys/cdefs.h>
7 __FBSDID("$FreeBSD$");
8 
9 #include <float.h>
10 
11 static const int map[] = {
12 	1,	/* round to nearest */
13 	3,	/* round to zero */
14 	2,	/* round to negative infinity */
15 	0	/* round to positive infinity */
16 };
17 
18 int
19 __flt_rounds(void)
20 {
21 	int x;
22 
23         /* Assume that the x87 and the SSE unit agree on the rounding mode. */
24 	__asm("fnstcw %0" : "=m" (x));
25         return (map[(x >> 10) & 0x03]);
26 }
27