s_nextafterf.c revision 50476
12116Sjkh/* s_nextafterf.c -- float version of s_nextafter.c. 22116Sjkh * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com. 32116Sjkh */ 42116Sjkh 52116Sjkh/* 62116Sjkh * ==================================================== 72116Sjkh * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. 82116Sjkh * 92116Sjkh * Developed at SunPro, a Sun Microsystems, Inc. business. 102116Sjkh * Permission to use, copy, modify, and distribute this 118870Srgrimes * software is freely granted, provided that this notice 122116Sjkh * is preserved. 132116Sjkh * ==================================================== 142116Sjkh */ 152116Sjkh 162116Sjkh#ifndef lint 1750476Speterstatic char rcsid[] = "$FreeBSD: head/lib/msun/src/s_nextafterf.c 50476 1999-08-28 00:22:10Z peter $"; 182116Sjkh#endif 192116Sjkh 202116Sjkh#include "math.h" 212116Sjkh#include "math_private.h" 222116Sjkh 232116Sjkh#ifdef __STDC__ 242116Sjkh float nextafterf(float x, float y) 252116Sjkh#else 262116Sjkh float nextafterf(x,y) 272116Sjkh float x,y; 282116Sjkh#endif 292116Sjkh{ 302116Sjkh int32_t hx,hy,ix,iy; 312116Sjkh 322116Sjkh GET_FLOAT_WORD(hx,x); 332116Sjkh GET_FLOAT_WORD(hy,y); 342116Sjkh ix = hx&0x7fffffff; /* |x| */ 352116Sjkh iy = hy&0x7fffffff; /* |y| */ 362116Sjkh 378870Srgrimes if((ix>0x7f800000) || /* x is nan */ 388870Srgrimes (iy>0x7f800000)) /* y is nan */ 398870Srgrimes return x+y; 402116Sjkh if(x==y) return x; /* x=y, return x */ 412116Sjkh if(ix==0) { /* x == 0 */ 422116Sjkh SET_FLOAT_WORD(x,(hy&0x80000000)|1);/* return +-minsubnormal */ 432116Sjkh y = x*x; 442116Sjkh if(y==x) return y; else return x; /* raise underflow flag */ 458870Srgrimes } 462116Sjkh if(hx>=0) { /* x > 0 */ 472116Sjkh if(hx>hy) { /* x > y, x -= ulp */ 482116Sjkh hx -= 1; 492116Sjkh } else { /* x < y, x += ulp */ 502116Sjkh hx += 1; 512116Sjkh } 522116Sjkh } else { /* x < 0 */ 532116Sjkh if(hy>=0||hx>hy){ /* x < y, x -= ulp */ 542116Sjkh hx -= 1; 552116Sjkh } else { /* x > y, x += ulp */ 562116Sjkh hx += 1; 572116Sjkh } 582116Sjkh } 592116Sjkh hy = hx&0x7f800000; 602116Sjkh if(hy>=0x7f800000) return x+x; /* overflow */ 612116Sjkh if(hy<0x00800000) { /* underflow */ 622116Sjkh y = x*x; 632116Sjkh if(y!=x) { /* raise underflow flag */ 642116Sjkh SET_FLOAT_WORD(y,hx); 652116Sjkh return y; 662116Sjkh } 672116Sjkh } 682116Sjkh SET_FLOAT_WORD(x,hx); 692116Sjkh return x; 702116Sjkh} 71