1 /* s_logbf.c -- float version of s_logb.c. 2 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@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