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/* @(#)w_pow.c 5.2 93/10/01 */
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/* @(#)w_pow.c 5.2 93/10/01 */
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/*
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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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* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
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*
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*
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* Developed at SunPro, a Sun Microsystems, Inc. business.
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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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* Permission to use, copy, modify, and distribute this
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* software is freely granted, provided that this notice
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* software is freely granted, provided that this notice
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* is preserved.
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* is preserved.
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* ====================================================
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* ====================================================
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*/
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*/
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/*
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/*
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FUNCTION
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FUNCTION
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<<pow>>, <<powf>>---x to the power y
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<<pow>>, <<powf>>---x to the power y
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INDEX
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INDEX
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pow
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pow
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INDEX
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INDEX
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powf
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powf
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ANSI_SYNOPSIS
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ANSI_SYNOPSIS
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#include <math.h>
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#include <math.h>
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double pow(double <[x]>, double <[y]>);
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double pow(double <[x]>, double <[y]>);
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float pow(float <[x]>, float <[y]>);
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float pow(float <[x]>, float <[y]>);
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TRAD_SYNOPSIS
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TRAD_SYNOPSIS
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#include <math.h>
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#include <math.h>
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double pow(<[x]>, <[y]>);
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double pow(<[x]>, <[y]>);
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double <[x]>, <[y]>;
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double <[x]>, <[y]>;
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float pow(<[x]>, <[y]>);
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float pow(<[x]>, <[y]>);
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float <[x]>, <[y]>;
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float <[x]>, <[y]>;
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DESCRIPTION
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DESCRIPTION
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<<pow>> and <<powf>> calculate <[x]> raised to the exp1.0nt <[y]>.
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<<pow>> and <<powf>> calculate <[x]> raised to the exp1.0nt <[y]>.
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@tex
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@tex
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(That is, $x^y$.)
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(That is, $x^y$.)
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@end tex
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@end tex
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RETURNS
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RETURNS
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On success, <<pow>> and <<powf>> return the value calculated.
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On success, <<pow>> and <<powf>> return the value calculated.
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When the argument values would produce overflow, <<pow>>
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When the argument values would produce overflow, <<pow>>
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returns <<HUGE_VAL>> and set <<errno>> to <<ERANGE>>. If the
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returns <<HUGE_VAL>> and set <<errno>> to <<ERANGE>>. If the
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argument <[x]> passed to <<pow>> or <<powf>> is a negative
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argument <[x]> passed to <<pow>> or <<powf>> is a negative
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noninteger, and <[y]> is also not an integer, then <<errno>>
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noninteger, and <[y]> is also not an integer, then <<errno>>
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is set to <<EDOM>>. If <[x]> and <[y]> are both 0, then
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is set to <<EDOM>>. If <[x]> and <[y]> are both 0, then
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<<pow>> and <<powf>> return <<1>>.
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<<pow>> and <<powf>> return <<1>>.
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You can modify error handling for these functions using <<matherr>>.
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You can modify error handling for these functions using <<matherr>>.
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PORTABILITY
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PORTABILITY
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<<pow>> is ANSI C. <<powf>> is an extension. */
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<<pow>> is ANSI C. <<powf>> is an extension. */
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/*
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/*
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* wrapper pow(x,y) return x**y
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* wrapper pow(x,y) return x**y
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*/
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*/
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#include "fdlibm.h"
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#include "fdlibm.h"
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#include <errno.h>
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#include <errno.h>
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#ifndef _DOUBLE_IS_32BITS
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#ifndef _DOUBLE_IS_32BITS
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#ifdef __STDC__
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#ifdef __STDC__
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double pow(double x, double y) /* wrapper pow */
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double pow(double x, double y) /* wrapper pow */
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#else
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#else
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double pow(x,y) /* wrapper pow */
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double pow(x,y) /* wrapper pow */
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double x,y;
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double x,y;
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#endif
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#endif
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{
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{
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#ifdef _IEEE_LIBM
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#ifdef _IEEE_LIBM
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return __ieee754_pow(x,y);
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return __ieee754_pow(x,y);
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#else
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#else
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double z;
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double z;
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#ifndef HUGE_VAL
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#ifndef HUGE_VAL
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#define HUGE_VAL inf
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#define HUGE_VAL inf
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double inf = 0.0;
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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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SET_HIGH_WORD(inf,0x7ff00000); /* set inf to infinite */
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#endif
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#endif
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struct exception exc;
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struct exception exc;
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z=__ieee754_pow(x,y);
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z=__ieee754_pow(x,y);
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if(_LIB_VERSION == _IEEE_|| isnan(y)) return z;
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if(_LIB_VERSION == _IEEE_|| isnan(y)) return z;
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if(isnan(x)) {
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if(isnan(x)) {
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if(y==0.0) {
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if(y==0.0) {
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/* pow(NaN,0.0) */
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/* pow(NaN,0.0) */
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/* error only if _LIB_VERSION == _SVID_ & _XOPEN_ */
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/* error only if _LIB_VERSION == _SVID_ & _XOPEN_ */
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exc.type = DOMAIN;
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exc.type = DOMAIN;
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exc.name = "pow";
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exc.name = "pow";
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exc.err = 0;
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exc.arg1 = x;
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exc.arg2 = y;
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exc.retval = x;
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exc.retval = x;
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if (_LIB_VERSION == _IEEE_ ||
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if (_LIB_VERSION == _IEEE_ ||
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_LIB_VERSION == _POSIX_) exc.retval = 1.0;
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_LIB_VERSION == _POSIX_) exc.retval = 1.0;
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else if (!matherr(&exc)) {
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else if (!matherr(&exc)) {
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errno = EDOM;
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errno = EDOM;
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}
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}
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if (exc.err != 0)
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if (exc.err != 0)
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errno = exc.err;
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errno = exc.err;
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return exc.retval;
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return exc.retval;
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} else
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} else
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return z;
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return z;
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}
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}
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if(x==0.0){
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if(x==0.0){
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if(y==0.0) {
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if(y==0.0) {
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/* pow(0.0,0.0) */
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/* pow(0.0,0.0) */
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/* error only if _LIB_VERSION == _SVID_ */
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/* error only if _LIB_VERSION == _SVID_ */
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exc.type = DOMAIN;
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exc.type = DOMAIN;
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exc.name = "pow";
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exc.name = "pow";
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exc.err = 0;
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exc.arg1 = x;
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exc.arg2 = y;
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exc.retval = 0.0;
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exc.retval = 0.0;
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if (_LIB_VERSION != _SVID_) exc.retval = 1.0;
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if (_LIB_VERSION != _SVID_) exc.retval = 1.0;
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else if (!matherr(&exc)) {
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else if (!matherr(&exc)) {
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errno = EDOM;
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errno = EDOM;
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}
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}
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if (exc.err != 0)
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if (exc.err != 0)
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errno = exc.err;
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errno = exc.err;
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return exc.retval;
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return exc.retval;
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}
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}
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if(finite(y)&&y<0.0) {
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if(finite(y)&&y<0.0) {
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/* 0**neg */
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/* 0**neg */
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exc.type = DOMAIN;
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exc.type = DOMAIN;
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exc.name = "pow";
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exc.name = "pow";
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exc.err = 0;
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exc.arg1 = x;
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exc.arg2 = y;
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if (_LIB_VERSION == _SVID_)
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if (_LIB_VERSION == _SVID_)
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exc.retval = 0.0;
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exc.retval = 0.0;
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else
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else
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exc.retval = -HUGE_VAL;
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exc.retval = -HUGE_VAL;
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if (_LIB_VERSION == _POSIX_)
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if (_LIB_VERSION == _POSIX_)
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errno = EDOM;
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errno = EDOM;
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else if (!matherr(&exc)) {
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else if (!matherr(&exc)) {
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errno = EDOM;
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errno = EDOM;
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}
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}
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if (exc.err != 0)
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if (exc.err != 0)
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errno = exc.err;
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errno = exc.err;
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return exc.retval;
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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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return z;
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}
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}
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if(!finite(z)) {
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if(!finite(z)) {
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if(finite(x)&&finite(y)) {
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if(finite(x)&&finite(y)) {
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if(isnan(z)) {
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if(isnan(z)) {
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/* neg**non-integral */
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/* neg**non-integral */
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exc.type = DOMAIN;
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exc.type = DOMAIN;
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exc.name = "pow";
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exc.name = "pow";
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exc.err = 0;
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exc.arg1 = x;
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exc.arg2 = y;
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if (_LIB_VERSION == _SVID_)
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if (_LIB_VERSION == _SVID_)
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exc.retval = 0.0;
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exc.retval = 0.0;
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else
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else
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exc.retval = 0.0/0.0; /* X/Open allow NaN */
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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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if (_LIB_VERSION == _POSIX_)
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errno = EDOM;
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errno = EDOM;
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else if (!matherr(&exc)) {
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else if (!matherr(&exc)) {
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errno = EDOM;
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errno = EDOM;
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}
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}
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if (exc.err != 0)
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if (exc.err != 0)
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errno = exc.err;
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errno = exc.err;
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return exc.retval;
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return exc.retval;
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} else {
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} else {
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/* pow(x,y) overflow */
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/* pow(x,y) overflow */
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exc.type = OVERFLOW;
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exc.type = OVERFLOW;
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exc.name = "pow";
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exc.name = "pow";
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exc.err = 0;
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exc.arg1 = x;
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exc.arg2 = y;
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if (_LIB_VERSION == _SVID_) {
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if (_LIB_VERSION == _SVID_) {
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exc.retval = HUGE;
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exc.retval = HUGE;
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y *= 0.5;
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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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if(x<0.0&&rint(y)!=y) exc.retval = -HUGE;
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} else {
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} else {
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exc.retval = HUGE_VAL;
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exc.retval = HUGE_VAL;
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y *= 0.5;
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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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if(x<0.0&&rint(y)!=y) exc.retval = -HUGE_VAL;
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}
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}
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if (_LIB_VERSION == _POSIX_)
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if (_LIB_VERSION == _POSIX_)
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errno = ERANGE;
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errno = ERANGE;
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else if (!matherr(&exc)) {
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else if (!matherr(&exc)) {
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errno = ERANGE;
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errno = ERANGE;
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}
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}
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if (exc.err != 0)
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if (exc.err != 0)
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errno = exc.err;
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errno = exc.err;
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return exc.retval;
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return exc.retval;
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}
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}
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}
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}
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}
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}
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if(z==0.0&&finite(x)&&finite(y)) {
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if(z==0.0&&finite(x)&&finite(y)) {
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/* pow(x,y) underflow */
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/* pow(x,y) underflow */
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exc.type = UNDERFLOW;
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exc.type = UNDERFLOW;
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exc.name = "pow";
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exc.name = "pow";
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exc.err = 0;
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exc.arg1 = x;
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exc.arg2 = y;
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exc.retval = 0.0;
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exc.retval = 0.0;
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if (_LIB_VERSION == _POSIX_)
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if (_LIB_VERSION == _POSIX_)
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errno = ERANGE;
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errno = ERANGE;
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else if (!matherr(&exc)) {
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else if (!matherr(&exc)) {
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errno = ERANGE;
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errno = ERANGE;
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}
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}
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if (exc.err != 0)
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if (exc.err != 0)
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errno = exc.err;
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errno = exc.err;
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return exc.retval;
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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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return z;
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#endif
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#endif
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}
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}
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#endif /* defined(_DOUBLE_IS_32BITS) */
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#endif /* defined(_DOUBLE_IS_32BITS) */
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