49 lines
1.0 KiB
C
49 lines
1.0 KiB
C
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/* sf_logb.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 "fdlibm.h"
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#ifdef __STDC__
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float logbf(float x)
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#else
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float logbf(x)
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float x;
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#endif
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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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#ifdef _DOUBLE_IS_32BITS
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#ifdef __STDC__
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double logb(double x)
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#else
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double logb(x)
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double x;
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#endif
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{
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return (double) logbf((float) x);
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}
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#endif /* defined(_DOUBLE_IS_32BITS) */
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