s_logbf.c revision 153049 
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 153049 2005-12-03 11:57:19Z bde $";
182116Sjkh#endif
192116Sjkh
202116Sjkh#include "math.h"
212116Sjkh#include "math_private.h"
222116Sjkh
23153049Sbdestatic const float
24153049Sbdetwo25 = 3.355443200e+07;		/* 0x4c000000 */
25153049Sbde
2697413Salfredfloat
2797413Salfredlogbf(float x)
282116Sjkh{
292116Sjkh	int32_t ix;
302116Sjkh	GET_FLOAT_WORD(ix,x);
312116Sjkh	ix &= 0x7fffffff;			/* high |x| */
322116Sjkh	if(ix==0) return (float)-1.0/fabsf(x);
332116Sjkh	if(ix>=0x7f800000) return x*x;
34153049Sbde	if(ix<0x00800000) {
35153049Sbde		x *= two25;		 /* convert subnormal x to normal */
36153049Sbde		GET_FLOAT_WORD(ix,x);
37153049Sbde		ix &= 0x7fffffff;
38153049Sbde		return (float) ((ix>>23)-127-25);
39153049Sbde	} else
40153049Sbde		return (float) ((ix>>23)-127);
412116Sjkh}
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