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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 2 | pj | 1 | /* s_rintf.c -- float version of s_rint.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_rintf.c,v 1.3 1996/08/28 16:34:36 bde 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 | /* |
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| 24 | * TWO23 is double instead of float to avoid a bug in gcc. Without |
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| 25 | * this, gcc thinks that TWO23[sx]+x and w-TWO23[sx] already have float |
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| 26 | * precision and doesn't clip them to float precision when they are |
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| 27 | * assigned and returned. |
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| 28 | */ |
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| 29 | #ifdef __STDC__ |
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| 30 | static const double |
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| 31 | #else |
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| 32 | static double |
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| 33 | #endif |
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| 34 | TWO23[2]={ |
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| 35 | 8.3886080000e+06, /* 0x4b000000 */ |
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| 36 | -8.3886080000e+06, /* 0xcb000000 */ |
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| 37 | }; |
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| 38 | |||
| 39 | #ifdef __STDC__ |
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| 40 | float rintf(float x) |
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| 41 | #else |
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| 42 | float rintf(x) |
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| 43 | float x; |
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| 44 | #endif |
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| 45 | { |
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| 46 | int32_t i0,j0,sx; |
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| 47 | u_int32_t i,i1; |
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| 48 | float w,t; |
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| 49 | GET_FLOAT_WORD(i0,x); |
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| 50 | sx = (i0>>31)&1; |
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| 51 | j0 = ((i0>>23)&0xff)-0x7f; |
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| 52 | if(j0<23) { |
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| 53 | if(j0<0) { |
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| 54 | if((i0&0x7fffffff)==0) return x; |
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| 55 | i1 = (i0&0x07fffff); |
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| 56 | i0 &= 0xfff00000; |
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| 57 | i0 |= ((i1|-i1)>>9)&0x400000; |
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| 58 | SET_FLOAT_WORD(x,i0); |
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| 59 | w = TWO23[sx]+x; |
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| 60 | t = w-TWO23[sx]; |
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| 61 | GET_FLOAT_WORD(i0,t); |
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| 62 | SET_FLOAT_WORD(t,(i0&0x7fffffff)|(sx<<31)); |
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| 63 | return t; |
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| 64 | } else { |
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| 65 | i = (0x007fffff)>>j0; |
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| 66 | if((i0&i)==0) return x; /* x is integral */ |
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| 67 | i>>=1; |
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| 68 | if((i0&i)!=0) i0 = (i0&(~i))|((0x100000)>>j0); |
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| 69 | } |
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| 70 | } else { |
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| 71 | if(j0==0x80) return x+x; /* inf or NaN */ |
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| 72 | else return x; /* x is integral */ |
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| 73 | } |
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| 74 | SET_FLOAT_WORD(x,i0); |
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| 75 | w = TWO23[sx]+x; |
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| 76 | return w-TWO23[sx]; |
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| 77 | } |