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104 lines
2.1 KiB
C
104 lines
2.1 KiB
C
/* wf_exp.c -- float version of w_exp.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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/*
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* wrapper expf(x)
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*/
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#include "fdlibm.h"
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#include <errno.h>
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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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o_threshold= 8.8721679688e+01, /* 0x42b17180 */
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u_threshold= -1.0397208405e+02; /* 0xc2cff1b5 */
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#ifdef __STDC__
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float expf(float x) /* wrapper expf */
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#else
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float expf(x) /* wrapper expf */
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float x;
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#endif
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{
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#ifdef _IEEE_LIBM
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return __ieee754_expf(x);
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#else
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float z;
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struct exception exc;
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z = __ieee754_expf(x);
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if(_LIB_VERSION == _IEEE_) return z;
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if(finitef(x)) {
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if(x>o_threshold) {
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/* expf(finite) overflow */
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#ifndef HUGE_VAL
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#define HUGE_VAL inf
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double inf = 0.0;
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SET_HIGH_WORD(inf,0x7ff00000); /* set inf to infinite */
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#endif
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exc.type = OVERFLOW;
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exc.name = "expf";
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exc.err = 0;
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exc.arg1 = exc.arg2 = (double)x;
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if (_LIB_VERSION == _SVID_)
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exc.retval = HUGE;
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else
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exc.retval = HUGE_VAL;
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if (_LIB_VERSION == _POSIX_)
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errno = ERANGE;
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else if (!matherr(&exc)) {
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errno = ERANGE;
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}
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if (exc.err != 0)
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errno = exc.err;
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return exc.retval;
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} else if(x<u_threshold) {
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/* expf(finite) underflow */
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exc.type = UNDERFLOW;
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exc.name = "expf";
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exc.err = 0;
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exc.arg1 = exc.arg2 = (double)x;
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exc.retval = 0.0;
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if (_LIB_VERSION == _POSIX_)
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errno = ERANGE;
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else if (!matherr(&exc)) {
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errno = ERANGE;
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}
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if (exc.err != 0)
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errno = exc.err;
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return exc.retval;
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}
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}
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return z;
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#endif
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}
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#ifdef _DOUBLE_IS_32BITS
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#ifdef __STDC__
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double exp(double x)
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#else
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double exp(x)
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double x;
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#endif
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{
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return (double) expf((float) x);
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}
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#endif /* defined(_DOUBLE_IS_32BITS) */
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