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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 2 | pj | 1 | /* s_floorf.c -- float version of s_floor.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_floorf.c,v 1.2 1995/05/30 05:49:40 rgrimes Exp $"; |
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| 18 | #endif |
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| 19 | |||
| 20 | /* |
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| 21 | * floorf(x) |
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| 22 | * Return x rounded toward -inf to integral value |
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| 23 | * Method: |
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| 24 | * Bit twiddling. |
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| 25 | * Exception: |
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| 26 | * Inexact flag raised if x not equal to floorf(x). |
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| 27 | */ |
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| 28 | |||
| 29 | #include "math.h" |
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| 30 | #include "math_private.h" |
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| 31 | |||
| 32 | #ifdef __STDC__ |
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| 33 | static const float huge = 1.0e30; |
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| 34 | #else |
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| 35 | static float huge = 1.0e30; |
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| 36 | #endif |
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| 37 | |||
| 38 | #ifdef __STDC__ |
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| 39 | float floorf(float x) |
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| 40 | #else |
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| 41 | float floorf(x) |
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| 42 | float x; |
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| 43 | #endif |
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| 44 | { |
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| 45 | int32_t i0,j0; |
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| 46 | u_int32_t i; |
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| 47 | GET_FLOAT_WORD(i0,x); |
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| 48 | j0 = ((i0>>23)&0xff)-0x7f; |
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| 49 | if(j0<23) { |
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| 50 | if(j0<0) { /* raise inexact if x != 0 */ |
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| 51 | if(huge+x>(float)0.0) {/* return 0*sign(x) if |x|<1 */ |
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| 52 | if(i0>=0) {i0=0;} |
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| 53 | else if((i0&0x7fffffff)!=0) |
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| 54 | { i0=0xbf800000;} |
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| 55 | } |
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| 56 | } else { |
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| 57 | i = (0x007fffff)>>j0; |
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| 58 | if((i0&i)==0) return x; /* x is integral */ |
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| 59 | if(huge+x>(float)0.0) { /* raise inexact flag */ |
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| 60 | if(i0<0) i0 += (0x00800000)>>j0; |
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| 61 | i0 &= (~i); |
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| 62 | } |
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| 63 | } |
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| 64 | } else { |
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| 65 | if(j0==0x80) return x+x; /* inf or NaN */ |
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| 66 | else return x; /* x is integral */ |
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| 67 | } |
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| 68 | SET_FLOAT_WORD(x,i0); |
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| 69 | return x; |
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| 70 | } |