180 lines
4.2 KiB
C
180 lines
4.2 KiB
C
/* wf_pow.c -- float version of w_pow.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 powf(x,y) return x**y
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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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float powf(float x, float y) /* wrapper powf */
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#else
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float powf(x,y) /* wrapper powf */
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float x,y;
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#endif
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{
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#ifdef _IEEE_LIBM
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return __ieee754_powf(x,y);
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#else
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float z;
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struct exception exc;
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z=__ieee754_powf(x,y);
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if(_LIB_VERSION == _IEEE_|| isnan(y)) return z;
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if(isnan(x)) {
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if(y==(float)0.0) {
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/* powf(NaN,0.0) */
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/* error only if _LIB_VERSION == _SVID_ & _XOPEN_ */
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exc.type = DOMAIN;
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exc.name = "powf";
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exc.err = 0;
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exc.arg1 = (double)x;
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exc.arg2 = (double)y;
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exc.retval = 1.0;
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if (_LIB_VERSION == _IEEE_ ||
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_LIB_VERSION == _POSIX_) exc.retval = 1.0;
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else if (!matherr(&exc)) {
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errno = EDOM;
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}
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if (exc.err != 0)
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errno = exc.err;
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return (float)exc.retval;
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} else
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return z;
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}
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if(x==(float)0.0){
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if(y==(float)0.0) {
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/* powf(0.0,0.0) */
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/* error only if _LIB_VERSION == _SVID_ */
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exc.type = DOMAIN;
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exc.name = "powf";
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exc.err = 0;
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exc.arg1 = (double)x;
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exc.arg2 = (double)y;
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exc.retval = 0.0;
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if (_LIB_VERSION != _SVID_) exc.retval = 1.0;
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else if (!matherr(&exc)) {
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errno = EDOM;
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}
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if (exc.err != 0)
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errno = exc.err;
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return (float)exc.retval;
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}
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if(finitef(y)&&y<(float)0.0) {
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/* 0**neg */
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exc.type = DOMAIN;
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exc.name = "powf";
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exc.err = 0;
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exc.arg1 = (double)x;
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exc.arg2 = (double)y;
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if (_LIB_VERSION == _SVID_)
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exc.retval = 0.0;
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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 = EDOM;
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else if (!matherr(&exc)) {
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errno = EDOM;
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}
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if (exc.err != 0)
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errno = exc.err;
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return (float)exc.retval;
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}
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return z;
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}
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if(!finitef(z)) {
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if(finitef(x)&&finitef(y)) {
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if(isnan(z)) {
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/* neg**non-integral */
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exc.type = DOMAIN;
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exc.name = "powf";
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exc.err = 0;
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exc.arg1 = (double)x;
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exc.arg2 = (double)y;
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if (_LIB_VERSION == _SVID_)
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exc.retval = 0.0;
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else
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exc.retval = 0.0/0.0; /* X/Open allow NaN */
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if (_LIB_VERSION == _POSIX_)
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errno = EDOM;
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else if (!matherr(&exc)) {
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errno = EDOM;
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}
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if (exc.err != 0)
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errno = exc.err;
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return (float)exc.retval;
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} else {
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/* powf(x,y) overflow */
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exc.type = OVERFLOW;
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exc.name = "powf";
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exc.err = 0;
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exc.arg1 = (double)x;
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exc.arg2 = (double)y;
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if (_LIB_VERSION == _SVID_) {
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exc.retval = HUGE;
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y *= 0.5;
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if(x<0.0&&rint(y)!=y) exc.retval = -HUGE;
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} else {
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exc.retval = HUGE_VAL;
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y *= 0.5;
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if(x<0.0&&rint(y)!=y) exc.retval = -HUGE_VAL;
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}
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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 (float)exc.retval;
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}
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}
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}
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if(z==(float)0.0&&finitef(x)&&finitef(y)) {
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/* powf(x,y) underflow */
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exc.type = UNDERFLOW;
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exc.name = "powf";
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exc.err = 0;
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exc.arg1 = (double)x;
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exc.arg2 = (double)y;
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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 (float)exc.retval;
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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 pow(double x, double y)
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#else
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double pow(x,y)
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double x,y;
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#endif
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{
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return (double) powf((float) x, (float) y);
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}
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#endif /* defined(_DOUBLE_IS_32BITS) */
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