37 lines
949 B
C
37 lines
949 B
C
/* s_logbf.c -- float version of s_logb.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 <sys/cdefs.h>
|
|
#if defined(LIBM_SCCS) && !defined(lint)
|
|
__RCSID("$NetBSD: s_logbf.c,v 1.7 2002/05/26 22:01:57 wiz Exp $");
|
|
#endif
|
|
|
|
#include "math.h"
|
|
#include "math_private.h"
|
|
|
|
float
|
|
logbf(float x)
|
|
{
|
|
int32_t ix;
|
|
GET_FLOAT_WORD(ix,x);
|
|
ix &= 0x7fffffff; /* high |x| */
|
|
if(ix==0) return (float)-1.0/fabsf(x);
|
|
if(ix>=0x7f800000) return x*x;
|
|
if((ix>>=23)==0) /* IEEE 754 logb */
|
|
return -126.0;
|
|
else
|
|
return (float) (ix-127);
|
|
}
|