1 /* 2 * ==================================================== 3 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. 4 * 5 * Developed at SunPro, a Sun Microsystems, Inc. business. 6 * Permission to use, copy, modify, and distribute this 7 * software is freely granted, provided that this notice 8 * is preserved. 9 * ==================================================== 10 */ 11 12 #ifndef lint 13 static char rcsid[] = "$FreeBSD: src/lib/msun/src/s_nexttowardf.c,v 1.1 2005/03/07 04:57:38 das Exp $"; 14 #endif 15 16 #include <float.h> 17 18 #include "fpmath.h" 19 #include "math.h" 20 #include "math_private.h" 21 22 #define LDBL_INFNAN_EXP (LDBL_MAX_EXP * 2 - 1) 23 24 float nexttowardf(float x,long double y)25 nexttowardf(float x, long double y) 26 { 27 union IEEEl2bits uy; 28 volatile float t; 29 int32_t hx,ix; 30 31 GET_FLOAT_WORD(hx,x); 32 ix = hx&0x7fffffff; /* |x| */ 33 uy.e = y; 34 35 if((ix>0x7f800000) || 36 (uy.bits.exp == LDBL_INFNAN_EXP && 37 ((uy.bits.manh&~LDBL_NBIT)|uy.bits.manl) != 0)) 38 return x+y; /* x or y is nan */ 39 if(x==y) return (float)y; /* x=y, return y */ 40 if(ix==0) { /* x == 0 */ 41 SET_FLOAT_WORD(x,(uy.bits.sign<<31)|1);/* return +-minsubnormal */ 42 t = x*x; 43 if(t==x) return t; else return x; /* raise underflow flag */ 44 } 45 if(hx>=0 ^ x < y) /* x -= ulp */ 46 hx -= 1; 47 else /* x += ulp */ 48 hx += 1; 49 ix = hx&0x7f800000; 50 if(ix>=0x7f800000) return x+x; /* overflow */ 51 if(ix<0x00800000) { /* underflow */ 52 t = x*x; 53 if(t!=x) { /* raise underflow flag */ 54 SET_FLOAT_WORD(y,hx); 55 return y; 56 } 57 } 58 SET_FLOAT_WORD(x,hx); 59 return x; 60 } 61