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 <sys/cdefs.h> 13 #include <float.h> 14 15 #include "fpmath.h" 16 #include "math.h" 17 #include "math_private.h" 18 19 #define LDBL_INFNAN_EXP (LDBL_MAX_EXP * 2 - 1) 20 21 float 22 nexttowardf(float x, long double y) 23 { 24 union IEEEl2bits uy; 25 volatile float t; 26 int32_t hx,ix; 27 28 GET_FLOAT_WORD(hx,x); 29 ix = hx&0x7fffffff; /* |x| */ 30 uy.e = y; 31 32 if((ix>0x7f800000) || 33 (uy.bits.exp == LDBL_INFNAN_EXP && 34 ((uy.bits.manh&~LDBL_NBIT)|uy.bits.manl) != 0)) 35 return x+y; /* x or y is nan */ 36 if(x==y) return (float)y; /* x=y, return y */ 37 if(ix==0) { /* x == 0 */ 38 SET_FLOAT_WORD(x,(uy.bits.sign<<31)|1);/* return +-minsubnormal */ 39 t = x*x; 40 if(t==x) return t; else return x; /* raise underflow flag */ 41 } 42 if(hx>=0 ^ x < y) /* x -= ulp */ 43 hx -= 1; 44 else /* x += ulp */ 45 hx += 1; 46 ix = hx&0x7f800000; 47 if(ix>=0x7f800000) return x+x; /* overflow */ 48 if(ix<0x00800000) { /* underflow */ 49 t = x*x; 50 if(t!=x) { /* raise underflow flag */ 51 SET_FLOAT_WORD(x,hx); 52 return x; 53 } 54 } 55 SET_FLOAT_WORD(x,hx); 56 return x; 57 } 58