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      1 /* s_logbf.c -- float version of s_logb.c.
      2  * Conversion to float by Ian Lance Taylor, Cygnus Support, ian (at) cygnus.com.
      3  */
      4 
      5 /*
      6  * ====================================================
      7  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
      8  *
      9  * Developed at SunPro, a Sun Microsystems, Inc. business.
     10  * Permission to use, copy, modify, and distribute this
     11  * software is freely granted, provided that this notice
     12  * is preserved.
     13  * ====================================================
     14  */
     15 
     16 #include <sys/cdefs.h>
     17 #if defined(LIBM_SCCS) && !defined(lint)
     18 __RCSID("$NetBSD: s_logbf.c,v 1.7 2002/05/26 22:01:57 wiz Exp $");
     19 #endif
     20 
     21 #include "math.h"
     22 #include "math_private.h"
     23 
     24 float
     25 logbf(float x)
     26 {
     27 	int32_t ix;
     28 	GET_FLOAT_WORD(ix,x);
     29 	ix &= 0x7fffffff;			/* high |x| */
     30 	if(ix==0) return (float)-1.0/fabsf(x);
     31 	if(ix>=0x7f800000) return x*x;
     32 	if((ix>>=23)==0) 			/* IEEE 754 logb */
     33 		return -126.0;
     34 	else
     35 		return (float) (ix-127);
     36 }
     37