| 1 | /* sf_floor.c -- float version of s_floor.c. |
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| 2 | * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com. |
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| 3 | */ |
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| 4 | |
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| 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 | |
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| 16 | /* |
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| 17 | * floorf(x) |
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| 18 | * Return x rounded toward -inf to integral value |
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| 19 | * Method: |
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| 20 | * Bit twiddling. |
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| 21 | * Exception: |
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| 22 | * Inexact flag raised if x not equal to floorf(x). |
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| 23 | */ |
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| 24 | |
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| 25 | #include "fdlibm.h" |
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| 26 | |
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| 27 | #ifdef __STDC__ |
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| 28 | static const float huge = 1.0e30; |
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| 29 | #else |
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| 30 | static float huge = 1.0e30; |
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| 31 | #endif |
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| 32 | |
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| 33 | #ifdef __STDC__ |
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| 34 | float floorf(float x) |
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| 35 | #else |
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| 36 | float floorf(x) |
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| 37 | float x; |
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| 38 | #endif |
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| 39 | { |
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| 40 | __int32_t i0,j0; |
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| 41 | __uint32_t i,ix; |
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| 42 | GET_FLOAT_WORD(i0,x); |
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| 43 | ix = (i0&0x7fffffff); |
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| 44 | j0 = (ix>>23)-0x7f; |
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| 45 | if(j0<23) { |
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| 46 | if(j0<0) { /* raise inexact if x != 0 */ |
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| 47 | if(huge+x>(float)0.0) {/* return 0*sign(x) if |x|<1 */ |
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| 48 | if(i0>=0) {i0=0;} |
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| 49 | else if(!FLT_UWORD_IS_ZERO(ix)) |
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| 50 | { i0=0xbf800000;} |
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| 51 | } |
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| 52 | } else { |
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| 53 | i = (0x007fffff)>>j0; |
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| 54 | if((i0&i)==0) return x; /* x is integral */ |
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| 55 | if(huge+x>(float)0.0) { /* raise inexact flag */ |
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| 56 | if(i0<0) i0 += (0x00800000)>>j0; |
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| 57 | i0 &= (~i); |
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| 58 | } |
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| 59 | } |
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| 60 | } else { |
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| 61 | if(!FLT_UWORD_IS_FINITE(ix)) return x+x; /* inf or NaN */ |
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| 62 | else return x; /* x is integral */ |
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| 63 | } |
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| 64 | SET_FLOAT_WORD(x,i0); |
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| 65 | return x; |
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| 66 | } |
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| 67 | |
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| 68 | #ifdef _DOUBLE_IS_32BITS |
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| 69 | |
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| 70 | #ifdef __STDC__ |
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| 71 | double floor(double x) |
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| 72 | #else |
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| 73 | double floor(x) |
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| 74 | double x; |
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| 75 | #endif |
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| 76 | { |
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| 77 | return (double) floorf((float) x); |
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| 78 | } |
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| 79 | |
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| 80 | #endif /* defined(_DOUBLE_IS_32BITS) */ |
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