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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 2 | pj | 1 | /* s_ilogbf.c -- float version of s_ilogb.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_ilogbf.c,v 1.2 1995/05/30 05:49:46 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 | int ilogbf(float x) |
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| 25 | #else |
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| 26 | int ilogbf(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 hx,ix; |
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| 31 | |||
| 32 | GET_FLOAT_WORD(hx,x); |
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| 33 | hx &= 0x7fffffff; |
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| 34 | if(hx<0x00800000) { |
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| 35 | if(hx==0) |
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| 36 | return 0x80000001; /* ilogb(0) = 0x80000001 */ |
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| 37 | else /* subnormal x */ |
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| 38 | for (ix = -126,hx<<=8; hx>0; hx<<=1) ix -=1; |
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| 39 | return ix; |
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| 40 | } |
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| 41 | else if (hx<0x7f800000) return (hx>>23)-127; |
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| 42 | else return 0x7fffffff; |
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| 43 | } |