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[/] [openrisc/] [trunk/] [gnu-old/] [newlib-1.17.0/] [newlib/] [libm/] [common/] [sf_scalbn.c] - Blame information for rev 158

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Line No. Rev Author Line
1 148 jeremybenn
/* sf_scalbn.c -- float version of s_scalbn.c.
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 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
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 */
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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 "fdlibm.h"
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#include <limits.h>
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#include <float.h>
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#if INT_MAX > 50000
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#define OVERFLOW_INT 50000
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#else
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#define OVERFLOW_INT 30000
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#endif
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#ifdef __STDC__
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static const float
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#else
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static float
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#endif
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two25   =  3.355443200e+07,     /* 0x4c000000 */
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twom25  =  2.9802322388e-08,    /* 0x33000000 */
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huge   = 1.0e+30,
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tiny   = 1.0e-30;
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#ifdef __STDC__
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        float scalbnf (float x, int n)
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#else
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        float scalbnf (x,n)
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        float x; int n;
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#endif
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{
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        __int32_t  k,ix;
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        __uint32_t hx;
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        GET_FLOAT_WORD(ix,x);
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        hx = ix&0x7fffffff;
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        k = hx>>23;             /* extract exponent */
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        if (FLT_UWORD_IS_ZERO(hx))
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            return x;
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        if (!FLT_UWORD_IS_FINITE(hx))
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            return x+x;         /* NaN or Inf */
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        if (FLT_UWORD_IS_SUBNORMAL(hx)) {
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            x *= two25;
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            GET_FLOAT_WORD(ix,x);
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            k = ((ix&0x7f800000)>>23) - 25;
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            if (n< -50000) return tiny*x;       /*underflow*/
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        }
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        k = k+n;
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        if (k > FLT_LARGEST_EXP) return huge*copysignf(huge,x); /* overflow  */
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        if (k > 0)                               /* normal result */
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            {SET_FLOAT_WORD(x,(ix&0x807fffff)|(k<<23)); return x;}
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        if (k < FLT_SMALLEST_EXP) {
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            if (n > OVERFLOW_INT)       /* in case integer overflow in n+k */
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                return huge*copysignf(huge,x);  /*overflow*/
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            else return tiny*copysignf(tiny,x); /*underflow*/
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        }
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        k += 25;                                /* subnormal result */
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        SET_FLOAT_WORD(x,(ix&0x807fffff)|(k<<23));
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        return x*twom25;
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}
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#ifdef _DOUBLE_IS_32BITS
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#ifdef __STDC__
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        double scalbn(double x, int n)
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#else
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        double scalbn(x,n)
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        double x;
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        int n;
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#endif
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{
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        return (double) scalbnf((float) x, n);
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}
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#endif /* defined(_DOUBLE_IS_32BITS) */

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