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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 3362 | Serge | 1 | /* sf_ilogb.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 | #include |
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| 17 | #include "fdlibm.h" |
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| 18 | |||
| 19 | #ifdef __STDC__ |
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| 20 | int ilogbf(float x) |
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| 21 | #else |
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| 22 | int ilogbf(x) |
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| 23 | float x; |
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| 24 | #endif |
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| 25 | { |
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| 26 | __int32_t hx,ix; |
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| 27 | |||
| 28 | GET_FLOAT_WORD(hx,x); |
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| 29 | hx &= 0x7fffffff; |
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| 30 | if(FLT_UWORD_IS_ZERO(hx)) |
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| 31 | return FP_ILOGB0; /* ilogb(0) = special case error */ |
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| 32 | if(FLT_UWORD_IS_SUBNORMAL(hx)) { |
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| 33 | for (ix = -126,hx<<=8; hx>0; hx<<=1) ix -=1; |
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| 34 | return ix; |
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| 35 | } |
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| 36 | #if FP_ILOGBNAN != INT_MAX |
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| 37 | else if (FLT_UWORD_IS_NAN(hx)) return FP_ILOGBNAN; /* NAN */ |
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| 38 | #endif |
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| 39 | else if (!FLT_UWORD_IS_FINITE(hx)) return INT_MAX; |
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| 40 | else return (hx>>23)-127; |
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| 41 | } |
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| 42 | |||
| 43 | #ifdef _DOUBLE_IS_32BITS |
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| 44 | |||
| 45 | #ifdef __STDC__ |
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| 46 | int ilogb(double x) |
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| 47 | #else |
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| 48 | int ilogb(x) |
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| 49 | double x; |
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| 50 | #endif |
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| 51 | { |
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| 52 | return ilogbf((float) x); |
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| 53 | } |
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| 54 | |||
| 55 | #endif /* defined(_DOUBLE_IS_32BITS) */ |