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 #ifndef lint 17 static char rcsid[] = "$Id: s_nextafterf.c,v 1.2 1994/08/18 23:07:15 jtc Exp $"; 18 #endif 19 20 #include "math.h" 21 #include "math_private.h" 22 23 #ifdef __STDC__ 24 float nextafterf(float x, float y) 25 #else 26 float nextafterf(x,y) 27 float x,y; 28 #endif 29 { 30 int32_t hx,hy,ix,iy; 31 32 GET_FLOAT_WORD(hx,x); 33 GET_FLOAT_WORD(hy,y); 34 ix = hx&0x7fffffff; /* |x| */ 35 iy = hy&0x7fffffff; /* |y| */ 36 37 if((ix>0x7f800000) || /* x is nan */ 38 (iy>0x7f800000)) /* y is nan */ 39 return x+y; 40 if(x==y) return x; /* x=y, return x */ 41 if(ix==0) { /* x == 0 */ 42 SET_FLOAT_WORD(x,(hy&0x80000000)|1);/* return +-minsubnormal */ 43 y = x*x; 44 if(y==x) return y; else return x; /* raise underflow flag */ 45 } 46 if(hx>=0) { /* x > 0 */ 47 if(hx>hy) { /* x > y, x -= ulp */ 48 hx -= 1; 49 } else { /* x < y, x += ulp */ 50 hx += 1; 51 } 52 } else { /* x < 0 */ 53 if(hy>=0||hx>hy){ /* x < y, x -= ulp */ 54 hx -= 1; 55 } else { /* x > y, x += ulp */ 56 hx += 1; 57 } 58 } 59 hy = hx&0x7f800000; 60 if(hy>=0x7f800000) return x+x; /* overflow */ 61 if(hy<0x00800000) { /* underflow */ 62 y = x*x; 63 if(y!=x) { /* raise underflow flag */ 64 SET_FLOAT_WORD(y,hx); 65 return y; 66 } 67 } 68 SET_FLOAT_WORD(x,hx); 69 return x; 70 } 71