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Viewing changes to android/bionic/libm/src/s_trunc.c

  • Committer: Package Import Robot
  • Author(s): Dmitrijs Ledkovs
  • Date: 2013-07-05 10:12:24 UTC
  • Revision ID: package-import@ubuntu.com-20130705101224-6qo3e8jbz8p31aa1
Tags: upstream-0.20130705.1
Import upstream version 0.20130705.1

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android/bionic/libm/src/s_trunc.c
 
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/* @(#)s_floor.c 5.1 93/09/24 */
 
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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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#include <sys/cdefs.h>
 
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/* __FBSDID("$FreeBSD: src/lib/msun/src/s_trunc.c,v 1.1 2004/06/20 09:25:43 das Exp $"); */
 
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/*
 
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 * trunc(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 trunc(x).
 
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 */
 
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#include "math.h"
 
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#include "math_private.h"
 
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static const double huge = 1.0e300;
 
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double
 
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trunc(double x)
 
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{
 
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        int32_t i0,i1,j0;
 
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        u_int32_t i,j;
 
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        EXTRACT_WORDS(i0,i1,x);
 
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        j0 = ((i0>>20)&0x7ff)-0x3ff;
 
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        if(j0<20) {
 
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            if(j0<0) {  /* raise inexact if x != 0 */
 
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                if(huge+x>0.0) {/* |x|<1, so return 0*sign(x) */
 
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                    i0 &= 0x80000000U;
 
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                    i1 = 0;
 
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                }
 
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            } else {
 
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                i = (0x000fffff)>>j0;
 
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                if(((i0&i)|i1)==0) return x; /* x is integral */
 
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                if(huge+x>0.0) {        /* raise inexact flag */
 
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                    i0 &= (~i); i1=0;
 
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                }
 
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            }
 
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        } else if (j0>51) {
 
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            if(j0==0x400) return x+x;   /* inf or NaN */
 
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            else return x;              /* x is integral */
 
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        } else {
 
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            i = ((u_int32_t)(0xffffffff))>>(j0-20);
 
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            if((i1&i)==0) return x;     /* x is integral */
 
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            if(huge+x>0.0)              /* raise inexact flag */
 
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                i1 &= (~i);
 
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        }
 
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        INSERT_WORDS(x,i0,i1);
 
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        return x;
 
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}