42 lines
1.0 KiB
C
42 lines
1.0 KiB
C
|
/* s_ilogbf.c -- float version of s_ilogb.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: src/lib/msun/src/s_ilogbf.c,v 1.7 2004/10/09 17:14:28 stefanf Exp $";
|
||
|
|
#endif
|
||
|
|
|
||
|
|
#include <limits.h>
|
||
|
|
|
||
|
|
#include "math.h"
|
||
|
|
#include "math_private.h"
|
||
|
|
|
||
|
|
int ilogbf(float x)
|
||
|
|
{
|
||
|
|
int32_t hx,ix;
|
||
|
|
|
||
|
|
GET_FLOAT_WORD(hx,x);
|
||
|
|
hx &= 0x7fffffff;
|
||
|
|
if(hx<0x00800000) {
|
||
|
|
if(hx==0)
|
||
|
|
return FP_ILOGB0;
|
||
|
|
else /* subnormal x */
|
||
|
|
for (ix = -126,hx<<=8; hx>0; hx<<=1) ix -=1;
|
||
|
|
return ix;
|
||
|
|
}
|
||
|
|
else if (hx<0x7f800000) return (hx>>23)-127;
|
||
|
|
else if (hx>0x7f800000) return FP_ILOGBNAN;
|
||
|
|
else return INT_MAX;
|
||
|
|
}
|