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Diffstat (limited to 'newlib/libm/math/w_pow.c')
| -rw-r--r-- | newlib/libm/math/w_pow.c | 231 |
1 files changed, 231 insertions, 0 deletions
diff --git a/newlib/libm/math/w_pow.c b/newlib/libm/math/w_pow.c new file mode 100644 index 00000000000..3df099a1714 --- /dev/null +++ b/newlib/libm/math/w_pow.c @@ -0,0 +1,231 @@ + + +/* @(#)w_pow.c 5.2 93/10/01 */ +/* + * ==================================================== + * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. + * + * Developed at SunPro, a Sun Microsystems, Inc. business. + * Permission to use, copy, modify, and distribute this + * software is freely granted, provided that this notice + * is preserved. + * ==================================================== + */ + +/* +FUNCTION + <<pow>>, <<powf>>---x to the power y +INDEX + pow +INDEX + powf + + +ANSI_SYNOPSIS + #include <math.h> + double pow(double <[x]>, double <[y]>); + float pow(float <[x]>, float <[y]>); + +TRAD_SYNOPSIS + #include <math.h> + double pow(<[x]>, <[y]>); + double <[x]>, <[y]>; + + float pow(<[x]>, <[y]>); + float <[x]>, <[y]>; + +DESCRIPTION + <<pow>> and <<powf>> calculate <[x]> raised to the exp1.0nt <[y]>. + @tex + (That is, $x^y$.) + @end tex + +RETURNS + On success, <<pow>> and <<powf>> return the value calculated. + + When the argument values would produce overflow, <<pow>> + returns <<HUGE_VAL>> and set <<errno>> to <<ERANGE>>. If the + argument <[x]> passed to <<pow>> or <<powf>> is a negative + noninteger, and <[y]> is also not an integer, then <<errno>> + is set to <<EDOM>>. If <[x]> and <[y]> are both 0, then + <<pow>> and <<powf>> return <<1>>. + + You can modify error handling for these functions using <<matherr>>. + +PORTABILITY + <<pow>> is ANSI C. <<powf>> is an extension. */ + +/* + * wrapper pow(x,y) return x**y + */ + +#include "fdlibm.h" +#include <errno.h> + +#ifndef _DOUBLE_IS_32BITS + +#ifdef __STDC__ + double pow(double x, double y) /* wrapper pow */ +#else + double pow(x,y) /* wrapper pow */ + double x,y; +#endif +{ +#ifdef _IEEE_LIBM + return __ieee754_pow(x,y); +#else + double z; +#ifndef HUGE_VAL +#define HUGE_VAL inf + double inf = 0.0; + + SET_HIGH_WORD(inf,0x7ff00000); /* set inf to infinite */ +#endif + struct exception exc; + z=__ieee754_pow(x,y); + if(_LIB_VERSION == _IEEE_|| isnan(y)) return z; + if(isnan(x)) { + if(y==0.0) { + /* pow(NaN,0.0) */ + /* error only if _LIB_VERSION == _SVID_ & _XOPEN_ */ + exc.type = DOMAIN; + exc.name = "pow"; + exc.err = 0; + exc.arg1 = x; + exc.arg2 = y; + exc.retval = x; + if (_LIB_VERSION == _IEEE_ || + _LIB_VERSION == _POSIX_) exc.retval = 1.0; + else if (!matherr(&exc)) { + errno = EDOM; + } + if (exc.err != 0) + errno = exc.err; + return exc.retval; + } else + return z; + } + if(x==0.0){ + if(y==0.0) { + /* pow(0.0,0.0) */ + /* error only if _LIB_VERSION == _SVID_ */ + exc.type = DOMAIN; + exc.name = "pow"; + exc.err = 0; + exc.arg1 = x; + exc.arg2 = y; + exc.retval = 0.0; + if (_LIB_VERSION != _SVID_) exc.retval = 1.0; + else if (!matherr(&exc)) { + errno = EDOM; + } + if (exc.err != 0) + errno = exc.err; + return exc.retval; + } + if(finite(y)&&y<0.0) { + /* 0**neg */ + exc.type = DOMAIN; + exc.name = "pow"; + exc.err = 0; + exc.arg1 = x; + exc.arg2 = y; + if (_LIB_VERSION == _SVID_) + exc.retval = 0.0; + else + exc.retval = -HUGE_VAL; + if (_LIB_VERSION == _POSIX_) + errno = EDOM; + else if (!matherr(&exc)) { + errno = EDOM; + } + if (exc.err != 0) + errno = exc.err; + return exc.retval; + } + return z; + } + if(!finite(z)) { + if(finite(x)&&finite(y)) { + if(isnan(z)) { + /* neg**non-integral */ + exc.type = DOMAIN; + exc.name = "pow"; + exc.err = 0; + exc.arg1 = x; + exc.arg2 = y; + if (_LIB_VERSION == _SVID_) + exc.retval = 0.0; + else + exc.retval = 0.0/0.0; /* X/Open allow NaN */ + if (_LIB_VERSION == _POSIX_) + errno = EDOM; + else if (!matherr(&exc)) { + errno = EDOM; + } + if (exc.err != 0) + errno = exc.err; + return exc.retval; + } else { + /* pow(x,y) overflow */ + exc.type = OVERFLOW; + exc.name = "pow"; + exc.err = 0; + exc.arg1 = x; + exc.arg2 = y; + if (_LIB_VERSION == _SVID_) { + exc.retval = HUGE; + y *= 0.5; + if(x<0.0&&rint(y)!=y) exc.retval = -HUGE; + } else { + exc.retval = HUGE_VAL; + y *= 0.5; + if(x<0.0&&rint(y)!=y) exc.retval = -HUGE_VAL; + } + if (_LIB_VERSION == _POSIX_) + errno = ERANGE; + else if (!matherr(&exc)) { + errno = ERANGE; + } + if (exc.err != 0) + errno = exc.err; + return exc.retval; + } + } + } + if(z==0.0&&finite(x)&&finite(y)) { + /* pow(x,y) underflow */ + exc.type = UNDERFLOW; + exc.name = "pow"; + exc.err = 0; + exc.arg1 = x; + exc.arg2 = y; + exc.retval = 0.0; + if (_LIB_VERSION == _POSIX_) + errno = ERANGE; + else if (!matherr(&exc)) { + errno = ERANGE; + } + if (exc.err != 0) + errno = exc.err; + return exc.retval; + } + return z; +#endif +} + +#endif /* defined(_DOUBLE_IS_32BITS) */ + + + + + + + + + + + + + + |