1 /* $OpenBSD: s_trunc.c,v 1.8 2016/09/12 19:47:02 guenther Exp $ */ 2 /* 3 * Written by Michael Shalayeff. Public Domain 4 */ 5 6 #include <sys/types.h> 7 #include <machine/ieeefp.h> 8 #include "math.h" 9 10 double 11 trunc(double x) 12 { 13 u_int64_t ofpsr, fpsr; 14 15 __asm__ volatile("fstds %%fr0,0(%0)" :: "r" (&ofpsr) : "memory"); 16 fpsr = (ofpsr & ~((u_int64_t)FP_RM << (9 + 32))) | 17 ((u_int64_t)FP_RZ << (9 + 32)); 18 __asm__ volatile("fldds 0(%0), %%fr0" :: "r" (&fpsr) : "memory"); 19 20 __asm__ volatile("frnd,dbl %0,%0" : "+f" (x)); 21 22 __asm__ volatile("fldds 0(%0), %%fr0" :: "r" (&ofpsr) : "memory"); 23 return (x); 24 } 25 DEF_STD(trunc); 26 LDBL_UNUSED_CLONE(trunc); 27