40 lines
922 B
C
40 lines
922 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.
|
|
* ====================================================
|
|
*/
|
|
|
|
#ifndef lint
|
|
static char rcsid[] = "$FreeBSD$";
|
|
#endif
|
|
|
|
#include "math.h"
|
|
#include "math_private.h"
|
|
|
|
#ifdef __STDC__
|
|
float logbf(float x)
|
|
#else
|
|
float logbf(x)
|
|
float x;
|
|
#endif
|
|
{
|
|
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);
|
|
}
|