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Diffstat (limited to 'libjava/java/lang/w_log.c')
-rw-r--r-- | libjava/java/lang/w_log.c | 115 |
1 files changed, 115 insertions, 0 deletions
diff --git a/libjava/java/lang/w_log.c b/libjava/java/lang/w_log.c new file mode 100644 index 00000000000..dcc8b9762ec --- /dev/null +++ b/libjava/java/lang/w_log.c @@ -0,0 +1,115 @@ + +/* @(#)w_log.c 5.1 93/09/24 */ +/* + * ==================================================== + * 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 + <<log>>, <<logf>>---natural logarithms + +INDEX + log +INDEX + logf + +ANSI_SYNOPSIS + #include <math.h> + double log(double <[x]>); + float logf(float <[x]>); + +TRAD_SYNOPSIS + #include <math.h> + double log(<[x]>); + double <[x]>; + + float logf(<[x]>); + float <[x]>; + +DESCRIPTION +Return the natural logarithm of <[x]>, that is, its logarithm base e +(where e is the base of the natural system of logarithms, 2.71828@dots{}). +<<log>> and <<logf>> are identical save for the return and argument types. + +You can use the (non-ANSI) function <<matherr>> to specify error +handling for these functions. + +RETURNS +Normally, returns the calculated value. When <[x]> is zero, the +returned value is <<-HUGE_VAL>> and <<errno>> is set to <<ERANGE>>. +When <[x]> is negative, the returned value is <<-HUGE_VAL>> and +<<errno>> is set to <<EDOM>>. You can control the error behavior via +<<matherr>>. + +PORTABILITY +<<log>> is ANSI, <<logf>> is an extension. +*/ + +/* + * wrapper log(x) + */ + +#include "fdlibm.h" +#include <errno.h> + +#ifndef _DOUBLE_IS_32BITS + +#ifdef __STDC__ + double log(double x) /* wrapper log */ +#else + double log(x) /* wrapper log */ + double x; +#endif +{ +#ifdef _IEEE_LIBM + return __ieee754_log(x); +#else + double z; + struct exception exc; + z = __ieee754_log(x); + if(_LIB_VERSION == _IEEE_ || isnan(x) || x > 0.0) return z; +#ifndef HUGE_VAL +#define HUGE_VAL inf + double inf = 0.0; + + SET_HIGH_WORD(inf,0x7ff00000); /* set inf to infinite */ +#endif + exc.name = "log"; + exc.err = 0; + exc.arg1 = x; + exc.arg2 = x; + if (_LIB_VERSION == _SVID_) + exc.retval = -HUGE; + else + exc.retval = -HUGE_VAL; + if(x==0.0) { + /* log(0) */ + exc.type = SING; + if (_LIB_VERSION == _POSIX_) + errno = ERANGE; + else if (!matherr(&exc)) { + errno = EDOM; + } + } else { + /* log(x<0) */ + exc.type = DOMAIN; + if (_LIB_VERSION == _POSIX_) + errno = EDOM; + else if (!matherr(&exc)) { + errno = EDOM; + } + } + if (exc.err != 0) + errno = exc.err; + return exc.retval; +#endif +} + +#endif /* defined(_DOUBLE_IS_32BITS) */ |