1 /* s_nextafterf.c -- float version of s_nextafter.c. 2 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com. 3 */ 4 5 /* 6 * ==================================================== 7 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. 8 * 9 * Developed at SunPro, a Sun Microsystems, Inc. business. 10 * Permission to use, copy, modify, and distribute this 11 * software is freely granted, provided that this notice 12 * is preserved. 13 * ==================================================== 14 */ 15 16 #include "cdefs-compat.h" 17 //__FBSDID("$FreeBSD: src/lib/msun/src/s_nextafterf.c,v 1.11 2008/02/22 02:30:35 das Exp $"); 18 19 #include <openlibm_math.h> 20 21 #include "math_private.h" 22 23 DLLEXPORT float 24 nextafterf(float x, float y) 25 { 26 volatile float t; 27 int32_t hx,hy,ix,iy; 28 29 GET_FLOAT_WORD(hx,x); 30 GET_FLOAT_WORD(hy,y); 31 ix = hx&0x7fffffff; /* |x| */ 32 iy = hy&0x7fffffff; /* |y| */ 33 34 if((ix>0x7f800000) || /* x is nan */ 35 (iy>0x7f800000)) /* y is nan */ 36 return x+y; 37 if(x==y) return y; /* x=y, return y */ 38 if(ix==0) { /* x == 0 */ 39 SET_FLOAT_WORD(x,(hy&0x80000000)|1);/* return +-minsubnormal */ 40 t = x*x; 41 if(t==x) return t; else return x; /* raise underflow flag */ 42 } 43 if(hx>=0) { /* x > 0 */ 44 if(hx>hy) { /* x > y, x -= ulp */ 45 hx -= 1; 46 } else { /* x < y, x += ulp */ 47 hx += 1; 48 } 49 } else { /* x < 0 */ 50 if(hy>=0||hx>hy){ /* x < y, x -= ulp */ 51 hx -= 1; 52 } else { /* x > y, x += ulp */ 53 hx += 1; 54 } 55 } 56 hy = hx&0x7f800000; 57 if(hy>=0x7f800000) return x+x; /* overflow */ 58 if(hy<0x00800000) { /* underflow */ 59 t = x*x; 60 if(t!=x) { /* raise underflow flag */ 61 SET_FLOAT_WORD(y,hx); 62 return y; 63 } 64 } 65 SET_FLOAT_WORD(x,hx); 66 return x; 67 } 68