0,0 → 1,79 |
/* sf_nextafter.c -- float version of s_nextafter.c. |
* Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com. |
*/ |
|
/* |
* ==================================================== |
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. |
* |
* Developed at SunPro, a Sun Microsystems, Inc. business. |
* Permission to use, copy, modify, and distribute this |
* software is freely granted, provided that this notice |
* is preserved. |
* ==================================================== |
*/ |
|
#include "fdlibm.h" |
|
#ifdef __STDC__ |
float nextafterf(float x, float y) |
#else |
float nextafterf(x,y) |
float x,y; |
#endif |
{ |
__int32_t hx,hy,ix,iy; |
|
GET_FLOAT_WORD(hx,x); |
GET_FLOAT_WORD(hy,y); |
ix = hx&0x7fffffff; /* |x| */ |
iy = hy&0x7fffffff; /* |y| */ |
|
if(FLT_UWORD_IS_NAN(ix) || |
FLT_UWORD_IS_NAN(iy)) |
return x+y; |
if(x==y) return x; /* x=y, return x */ |
if(FLT_UWORD_IS_ZERO(ix)) { /* x == 0 */ |
SET_FLOAT_WORD(x,(hy&0x80000000)|FLT_UWORD_MIN); |
y = x*x; |
if(y==x) return y; else return x; /* raise underflow flag */ |
} |
if(hx>=0) { /* x > 0 */ |
if(hx>hy) { /* x > y, x -= ulp */ |
hx -= 1; |
} else { /* x < y, x += ulp */ |
hx += 1; |
} |
} else { /* x < 0 */ |
if(hy>=0||hx>hy){ /* x < y, x -= ulp */ |
hx -= 1; |
} else { /* x > y, x += ulp */ |
hx += 1; |
} |
} |
hy = hx&0x7f800000; |
if(hy>FLT_UWORD_MAX) return x+x; /* overflow */ |
if(hy<0x00800000) { /* underflow */ |
y = x*x; |
if(y!=x) { /* raise underflow flag */ |
SET_FLOAT_WORD(y,hx); |
return y; |
} |
} |
SET_FLOAT_WORD(x,hx); |
return x; |
} |
|
#ifdef _DOUBLE_IS_32BITS |
|
#ifdef __STDC__ |
double nextafter(double x, double y) |
#else |
double nextafter(x,y) |
double x,y; |
#endif |
{ |
return (double) nextafterf((float) x, (float) x); |
} |
|
#endif /* defined(_DOUBLE_IS_32BITS) */ |