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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 2 | pj | 1 | /* s_logbf.c -- float version of s_logb.c. |
| 2 | * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com. |
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| 3 | */ |
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| 4 | |||
| 5 | /* |
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| 6 | * ==================================================== |
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| 7 | * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. |
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| 8 | * |
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| 9 | * Developed at SunPro, a Sun Microsystems, Inc. business. |
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| 10 | * Permission to use, copy, modify, and distribute this |
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| 11 | * software is freely granted, provided that this notice |
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| 12 | * is preserved. |
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| 13 | * ==================================================== |
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| 14 | */ |
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| 15 | |||
| 16 | #ifndef lint |
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| 17 | static char rcsid[] = "$\Id: s_logbf.c,v 1.2 1995/05/30 05:50:00 rgrimes Exp $"; |
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| 18 | #endif |
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| 19 | |||
| 20 | #include "math.h" |
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| 21 | #include "math_private.h" |
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| 22 | |||
| 23 | #ifdef __STDC__ |
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| 24 | float logbf(float x) |
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| 25 | #else |
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| 26 | float logbf(x) |
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| 27 | float x; |
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| 28 | #endif |
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| 29 | { |
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| 30 | int32_t ix; |
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| 31 | GET_FLOAT_WORD(ix,x); |
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| 32 | ix &= 0x7fffffff; /* high |x| */ |
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| 33 | if(ix==0) return (float)-1.0/fabsf(x); |
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| 34 | if(ix>=0x7f800000) return x*x; |
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| 35 | if((ix>>=23)==0) /* IEEE 754 logb */ |
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| 36 | return -126.0; |
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| 37 | else |
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| 38 | return (float) (ix-127); |
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| 39 | } |