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[/] [openrisc/] [trunk/] [gnu-src/] [newlib-1.18.0/] [newlib/] [libm/] [math/] [s_ceil.c] - Blame information for rev 252

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Line No. Rev Author Line
1 207 jeremybenn 
 
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/* @(#)s_ceil.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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/*
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 * ceil(x)
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 * Return x rounded toward -inf 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 ceil(x).
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 */
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#include "fdlibm.h"
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#ifndef _DOUBLE_IS_32BITS
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#ifdef __STDC__
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static const double huge = 1.0e300;
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#else
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static double huge = 1.0e300;
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#endif
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#ifdef __STDC__
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        double ceil(double x)
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#else
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        double ceil(x)
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        double x;
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#endif
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{
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        __int32_t i0,i1,j0;
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        __uint32_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) {/* return 0*sign(x) if |x|<1 */
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                    if(i0<0) {i0=0x80000000;i1=0;}
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                    else if((i0|i1)!=0) { i0=0x3ff00000;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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                    if(i0>0) i0 += (0x00100000)>>j0;
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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 = ((__uint32_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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                if(i0>0) {
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                    if(j0==20) i0+=1;
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                    else {
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                        j = i1 + (1<<(52-j0));
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                        if(j<i1) i0+=1; /* got a carry */
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                        i1 = j;
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                    }
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                }
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                i1 &= (~i);
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            }
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        }
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        INSERT_WORDS(x,i0,i1);
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        return x;
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}
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#endif /* _DOUBLE_IS_32BITS */

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