5980be9b3c
This work is based in part on code from NetBSD libm, libc and kernel. The library is partly public domain and partly BSD-style licensed.
37 lines
949 B
C
37 lines
949 B
C
/* s_logbf.c -- float version of s_logb.c.
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* Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
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*/
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/*
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* ====================================================
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* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
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*
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* Developed at SunPro, a Sun Microsystems, Inc. business.
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* Permission to use, copy, modify, and distribute this
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* software is freely granted, provided that this notice
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* is preserved.
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* ====================================================
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*/
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#include <sys/cdefs.h>
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#if defined(LIBM_SCCS) && !defined(lint)
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__RCSID("$NetBSD: s_logbf.c,v 1.7 2002/05/26 22:01:57 wiz Exp $");
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#endif
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#include "math.h"
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#include "math_private.h"
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float
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logbf(float x)
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{
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int32_t ix;
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GET_FLOAT_WORD(ix,x);
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ix &= 0x7fffffff; /* high |x| */
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if(ix==0) return (float)-1.0/fabsf(x);
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if(ix>=0x7f800000) return x*x;
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if((ix>>=23)==0) /* IEEE 754 logb */
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return -126.0;
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else
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return (float) (ix-127);
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}
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