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  • Committer: Package Import Robot
  • Author(s): Kevin Bortis
  • Date: 2013-09-20 20:54:14 UTC
  • Revision ID: package-import@ubuntu.com-20130920205414-5b61trtmma18w58o
Tags: upstream-0.9.13
Import upstream version 0.9.13

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src/math/truncf.c
 
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/* origin: FreeBSD /usr/src/lib/msun/src/s_truncf.c */
 
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/*
 
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 * ====================================================
 
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 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
 
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 *
 
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 * Developed at SunPro, a Sun Microsystems, Inc. business.
 
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 * Permission to use, copy, modify, and distribute this
 
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 * software is freely granted, provided that this notice
 
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 * is preserved.
 
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 * ====================================================
 
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 */
 
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/*
 
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 * truncf(x)
 
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 * Return x rounded toward 0 to integral value
 
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 * Method:
 
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 *      Bit twiddling.
 
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 * Exception:
 
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 *      Inexact flag raised if x not equal to truncf(x).
 
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 */
 
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#include "libm.h"
 
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static const float huge = 1.0e30f;
 
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float truncf(float x)
 
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{
 
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        int32_t i0,j0;
 
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        uint32_t i;
 
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        GET_FLOAT_WORD(i0, x);
 
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        j0 = ((i0>>23)&0xff) - 0x7f;
 
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        if (j0 < 23) {
 
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                if (j0 < 0) {  /* |x|<1, return 0*sign(x) */
 
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                        /* raise inexact if x != 0 */
 
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                        if (huge+x > 0.0f)
 
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                                i0 &= 0x80000000;
 
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                } else {
 
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                        i = 0x007fffff>>j0;
 
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                        if ((i0&i) == 0)
 
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                                return x; /* x is integral */
 
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                        /* raise inexact */
 
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                        if (huge+x > 0.0f)
 
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                                i0 &= ~i;
 
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                }
 
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        } else {
 
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                if (j0 == 0x80)
 
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                        return x + x;  /* inf or NaN */
 
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                return x;              /* x is integral */
 
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        }
 
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        SET_FLOAT_WORD(x, i0);
 
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        return x;
 
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}