s_logbf.c revision 97413 
12116Sjkh/* s_logbf.c -- float version of s_logb.c.
22116Sjkh * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
32116Sjkh */
42116Sjkh
52116Sjkh/*
62116Sjkh * ====================================================
72116Sjkh * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
82116Sjkh *
92116Sjkh * Developed at SunPro, a Sun Microsystems, Inc. business.
102116Sjkh * Permission to use, copy, modify, and distribute this
118870Srgrimes * software is freely granted, provided that this notice
122116Sjkh * is preserved.
132116Sjkh * ====================================================
142116Sjkh */
152116Sjkh
162116Sjkh#ifndef lint
1750476Speterstatic char rcsid[] = "$FreeBSD: head/lib/msun/src/s_logbf.c 97413 2002-05-28 18:15:04Z alfred $";
182116Sjkh#endif
192116Sjkh
202116Sjkh#include "math.h"
212116Sjkh#include "math_private.h"
222116Sjkh
2397413Salfredfloat
2497413Salfredlogbf(float x)
252116Sjkh{
262116Sjkh	int32_t ix;
272116Sjkh	GET_FLOAT_WORD(ix,x);
282116Sjkh	ix &= 0x7fffffff;			/* high |x| */
292116Sjkh	if(ix==0) return (float)-1.0/fabsf(x);
302116Sjkh	if(ix>=0x7f800000) return x*x;
312116Sjkh	if((ix>>=23)==0) 			/* IEEE 754 logb */
328870Srgrimes		return -126.0;
332116Sjkh	else
348870Srgrimes		return (float) (ix-127);
352116Sjkh}
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