| |
| /* @(#)w_lgamma.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. |
| * ==================================================== |
| * |
| */ |
| |
| /* double lgamma(double x) |
| * Return the logarithm of the Gamma function of x. |
| * |
| * Method: call __ieee754_lgamma_r |
| */ |
| |
| #include "fdlibm.h" |
| #include <reent.h> |
| #include <errno.h> |
| |
| #ifndef _DOUBLE_IS_32BITS |
| |
| #ifdef __STDC__ |
| double lgamma(double x) |
| #else |
| double lgamma(x) |
| double x; |
| #endif |
| { |
| #ifdef _IEEE_LIBM |
| return __ieee754_lgamma_r(x,&(_REENT_SIGNGAM(_REENT))); |
| #else |
| double y; |
| struct exception exc; |
| y = __ieee754_lgamma_r(x,&(_REENT_SIGNGAM(_REENT))); |
| if(_LIB_VERSION == _IEEE_) return y; |
| if(!finite(y)&&finite(x)) { |
| #ifndef HUGE_VAL |
| #define HUGE_VAL inf |
| double inf = 0.0; |
| |
| SET_HIGH_WORD(inf,0x7ff00000); /* set inf to infinite */ |
| #endif |
| exc.name = "lgamma"; |
| exc.err = 0; |
| exc.arg1 = x; |
| exc.arg2 = x; |
| if (_LIB_VERSION == _SVID_) |
| exc.retval = HUGE; |
| else |
| exc.retval = HUGE_VAL; |
| if(floor(x)==x&&x<=0.0) { |
| /* lgamma(-integer) */ |
| exc.type = SING; |
| if (_LIB_VERSION == _POSIX_) |
| errno = EDOM; |
| else if (!matherr(&exc)) { |
| errno = EDOM; |
| } |
| |
| } else { |
| /* lgamma(finite) overflow */ |
| exc.type = OVERFLOW; |
| if (_LIB_VERSION == _POSIX_) |
| errno = ERANGE; |
| else if (!matherr(&exc)) { |
| errno = ERANGE; |
| } |
| } |
| if (exc.err != 0) |
| errno = exc.err; |
| return exc.retval; |
| } else |
| return y; |
| #endif |
| } |
| |
| #endif /* defined(_DOUBLE_IS_32BITS) */ |
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