12116Sjkh/* @(#)s_nextafter.c 5.1 93/09/24 */ 22116Sjkh/* 32116Sjkh * ==================================================== 42116Sjkh * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. 52116Sjkh * 62116Sjkh * Developed at SunPro, a Sun Microsystems, Inc. business. 72116Sjkh * Permission to use, copy, modify, and distribute this 88870Srgrimes * software is freely granted, provided that this notice 92116Sjkh * is preserved. 102116Sjkh * ==================================================== 112116Sjkh */ 122116Sjkh 13176451Sdas#include <sys/cdefs.h> 14176451Sdas__FBSDID("$FreeBSD: releng/11.0/lib/msun/src/s_nextafter.c 176451 2008-02-22 02:30:36Z das $"); 152116Sjkh 162116Sjkh/* IEEE functions 172116Sjkh * nextafter(x,y) 182116Sjkh * return the next machine floating-point number of x in the 192116Sjkh * direction toward y. 202116Sjkh * Special cases: 212116Sjkh */ 222116Sjkh 23143216Sdas#include <float.h> 24143216Sdas 252116Sjkh#include "math.h" 262116Sjkh#include "math_private.h" 272116Sjkh 2897413Salfreddouble 2997413Salfrednextafter(double x, double y) 302116Sjkh{ 31143216Sdas volatile double t; 322116Sjkh int32_t hx,hy,ix,iy; 332116Sjkh u_int32_t lx,ly; 342116Sjkh 352116Sjkh EXTRACT_WORDS(hx,lx,x); 362116Sjkh EXTRACT_WORDS(hy,ly,y); 372116Sjkh ix = hx&0x7fffffff; /* |x| */ 382116Sjkh iy = hy&0x7fffffff; /* |y| */ 392116Sjkh 408870Srgrimes if(((ix>=0x7ff00000)&&((ix-0x7ff00000)|lx)!=0) || /* x is nan */ 418870Srgrimes ((iy>=0x7ff00000)&&((iy-0x7ff00000)|ly)!=0)) /* y is nan */ 428870Srgrimes return x+y; 43140685Sdas if(x==y) return y; /* x=y, return y */ 442116Sjkh if((ix|lx)==0) { /* x == 0 */ 452116Sjkh INSERT_WORDS(x,hy&0x80000000,1); /* return +-minsubnormal */ 46143216Sdas t = x*x; 47143216Sdas if(t==x) return t; else return x; /* raise underflow flag */ 488870Srgrimes } 492116Sjkh if(hx>=0) { /* x > 0 */ 502116Sjkh if(hx>hy||((hx==hy)&&(lx>ly))) { /* x > y, x -= ulp */ 512116Sjkh if(lx==0) hx -= 1; 522116Sjkh lx -= 1; 532116Sjkh } else { /* x < y, x += ulp */ 542116Sjkh lx += 1; 552116Sjkh if(lx==0) hx += 1; 562116Sjkh } 572116Sjkh } else { /* x < 0 */ 582116Sjkh if(hy>=0||hx>hy||((hx==hy)&&(lx>ly))){/* x < y, x -= ulp */ 592116Sjkh if(lx==0) hx -= 1; 602116Sjkh lx -= 1; 612116Sjkh } else { /* x > y, x += ulp */ 622116Sjkh lx += 1; 632116Sjkh if(lx==0) hx += 1; 642116Sjkh } 652116Sjkh } 662116Sjkh hy = hx&0x7ff00000; 672116Sjkh if(hy>=0x7ff00000) return x+x; /* overflow */ 682116Sjkh if(hy<0x00100000) { /* underflow */ 69143216Sdas t = x*x; 70143216Sdas if(t!=x) { /* raise underflow flag */ 712116Sjkh INSERT_WORDS(y,hx,lx); 722116Sjkh return y; 732116Sjkh } 742116Sjkh } 752116Sjkh INSERT_WORDS(x,hx,lx); 762116Sjkh return x; 772116Sjkh} 78143216Sdas 79143216Sdas#if (LDBL_MANT_DIG == 53) 80143264Sdas__weak_reference(nextafter, nexttoward); 81143264Sdas__weak_reference(nextafter, nexttowardl); 82143264Sdas__weak_reference(nextafter, nextafterl); 83143216Sdas#endif 84