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 #include <float.h> 13 14 #include "fpmath.h" 15 #include "math.h" 16 #include "math_private.h" 17 18 #define LDBL_INFNAN_EXP (LDBL_MAX_EXP * 2 - 1) 19 20 float 21 nexttowardf(float x, long double y) 22 { 23 union IEEEl2bits uy; 24 volatile float t; 25 int32_t hx,ix; 26 27 GET_FLOAT_WORD(hx,x); 28 ix = hx&0x7fffffff; /* |x| */ 29 uy.e = y; 30 31 if((ix>0x7f800000) || 32 (uy.bits.exp == LDBL_INFNAN_EXP && 33 ((uy.bits.manh&~LDBL_NBIT)|uy.bits.manl) != 0)) 34 return x+y; /* x or y is nan */ 35 if(x==y) return (float)y; /* x=y, return y */ 36 if(ix==0) { /* x == 0 */ 37 SET_FLOAT_WORD(x,(uy.bits.sign<<31)|1);/* return +-minsubnormal */ 38 t = x*x; 39 if(t==x) return t; else return x; /* raise underflow flag */ 40 } 41 if(hx>=0 ^ x < y) /* x -= ulp */ 42 hx -= 1; 43 else /* x += ulp */ 44 hx += 1; 45 ix = hx&0x7f800000; 46 if(ix>=0x7f800000) return x+x; /* overflow */ 47 if(ix<0x00800000) { /* underflow */ 48 t = x*x; 49 if(t!=x) { /* raise underflow flag */ 50 SET_FLOAT_WORD(x,hx); 51 return x; 52 } 53 } 54 SET_FLOAT_WORD(x,hx); 55 return x; 56 } 57