1/* $OpenBSD: s_trunc.c,v 1.9 2023/01/27 16:43:33 miod 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 10double 11trunc(double x) 12{ 13 u_int64_t ofpsr, fpsr; 14 15 __asm__ volatile("fstds %%fr0,0(%1)" : "=m" (ofpsr) : "r" (&ofpsr)); 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), "m" (fpsr)); 19 20 __asm__ volatile("frnd,dbl %0,%0" : "+f" (x)); 21 22 __asm__ volatile("fldds 0(%0), %%fr0" :: "r" (&ofpsr), "m" (ofpsr)); 23 return (x); 24} 25DEF_STD(trunc); 26LDBL_UNUSED_CLONE(trunc); 27