OpenLibm/src/s_nextafterf.c

68 lines
1.7 KiB
C
Raw Normal View History

/* s_nextafterf.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 "cdefs-compat.h"
2011-12-15 07:16:26 +01:00
//__FBSDID("$FreeBSD: src/lib/msun/src/s_nextafterf.c,v 1.11 2008/02/22 02:30:35 das Exp $");
#include <openlibm_math.h>
#include "math_private.h"
OLM_DLLEXPORT float
nextafterf(float x, float y)
{
volatile float t;
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((ix>0x7f800000) || /* x is nan */
(iy>0x7f800000)) /* y is nan */
return x+y;
if(x==y) return y; /* x=y, return y */
if(ix==0) { /* x == 0 */
SET_FLOAT_WORD(x,(hy&0x80000000)|1);/* return +-minsubnormal */
t = x*x;
if(t==x) return t; 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>=0x7f800000) return x+x; /* overflow */
if(hy<0x00800000) { /* underflow */
t = x*x;
if(t!=x) { /* raise underflow flag */
SET_FLOAT_WORD(y,hx);
return y;
}
}
SET_FLOAT_WORD(x,hx);
return x;
}