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newlib-cygwin/newlib/libm/math/e_tgamma.c

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import newlib-2000-02-17 snapshot
2000-02-18 03:39:52 +08:00
libm: Fix 'gamma' and 'gammaf' functions. Clean up other gamma code. [v2] The current gamma, gamma_r, gammaf and gammaf_r functions return |gamma(x)| instead of ln(|gamma(x)|) due to a change made back in 2002 to the __ieee754_gamma_r implementation. This patch fixes that, making all of these functions map too their lgamma equivalents. To fix the underlying bug, the __ieee754_gamma functions have been changed to return gamma(x), removing the _r variants as those are no longer necessary. Their names have been changed to __ieee754_tgamma to avoid potential confusion from users. Now that the __ieee754_tgamma functions return the correctly signed value, the tgamma functions have been modified to use them. libm.a now exposes the following gamma functions: ln(|gamma(x)|): __ieee754_lgamma_r __ieee754_lgammaf_r lgamma lgamma_r gamma gamma_r lgammaf lgammaf_r gammaf gammaf_r lgammal (on machines where long double is double) gamma(x): __ieee754_tgamma __ieee754_tgammaf tgamma tgammaf tgammal (on machines where long double is double) Additional aliases for any of the above functions can be added if necessary; in particular, I'm not sure if we need to include __ieee754_gamma*_r functions (which would return ln(|(gamma(x)|). Signed-off-by: Keith Packard <keithp@keithp.com> ---- v2: Switch commit message to ASCII
2020-09-05 00:25:27 +08:00
/* @(#)e_tgamma.c 5.1 93/09/24 */
import newlib-2000-02-17 snapshot
2000-02-18 03:39:52 +08:00
/*
* ====================================================
* 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.
* ====================================================
*
*/
libm: Fix 'gamma' and 'gammaf' functions. Clean up other gamma code. [v2] The current gamma, gamma_r, gammaf and gammaf_r functions return |gamma(x)| instead of ln(|gamma(x)|) due to a change made back in 2002 to the __ieee754_gamma_r implementation. This patch fixes that, making all of these functions map too their lgamma equivalents. To fix the underlying bug, the __ieee754_gamma functions have been changed to return gamma(x), removing the _r variants as those are no longer necessary. Their names have been changed to __ieee754_tgamma to avoid potential confusion from users. Now that the __ieee754_tgamma functions return the correctly signed value, the tgamma functions have been modified to use them. libm.a now exposes the following gamma functions: ln(|gamma(x)|): __ieee754_lgamma_r __ieee754_lgammaf_r lgamma lgamma_r gamma gamma_r lgammaf lgammaf_r gammaf gammaf_r lgammal (on machines where long double is double) gamma(x): __ieee754_tgamma __ieee754_tgammaf tgamma tgammaf tgammal (on machines where long double is double) Additional aliases for any of the above functions can be added if necessary; in particular, I'm not sure if we need to include __ieee754_gamma*_r functions (which would return ln(|(gamma(x)|). Signed-off-by: Keith Packard <keithp@keithp.com> ---- v2: Switch commit message to ASCII
2020-09-05 00:25:27 +08:00
/* __ieee754_tgamma(x)
* Gamma function. Returns gamma(x)
import newlib-2000-02-17 snapshot
2000-02-18 03:39:52 +08:00
*
* Method: See __ieee754_lgamma_r
*/
#include "fdlibm.h"
#ifdef __STDC__
libm: Fix 'gamma' and 'gammaf' functions. Clean up other gamma code. [v2] The current gamma, gamma_r, gammaf and gammaf_r functions return |gamma(x)| instead of ln(|gamma(x)|) due to a change made back in 2002 to the __ieee754_gamma_r implementation. This patch fixes that, making all of these functions map too their lgamma equivalents. To fix the underlying bug, the __ieee754_gamma functions have been changed to return gamma(x), removing the _r variants as those are no longer necessary. Their names have been changed to __ieee754_tgamma to avoid potential confusion from users. Now that the __ieee754_tgamma functions return the correctly signed value, the tgamma functions have been modified to use them. libm.a now exposes the following gamma functions: ln(|gamma(x)|): __ieee754_lgamma_r __ieee754_lgammaf_r lgamma lgamma_r gamma gamma_r lgammaf lgammaf_r gammaf gammaf_r lgammal (on machines where long double is double) gamma(x): __ieee754_tgamma __ieee754_tgammaf tgamma tgammaf tgammal (on machines where long double is double) Additional aliases for any of the above functions can be added if necessary; in particular, I'm not sure if we need to include __ieee754_gamma*_r functions (which would return ln(|(gamma(x)|). Signed-off-by: Keith Packard <keithp@keithp.com> ---- v2: Switch commit message to ASCII
2020-09-05 00:25:27 +08:00
double __ieee754_tgamma(double x)
import newlib-2000-02-17 snapshot
2000-02-18 03:39:52 +08:00
#else
libm: Fix 'gamma' and 'gammaf' functions. Clean up other gamma code. [v2] The current gamma, gamma_r, gammaf and gammaf_r functions return |gamma(x)| instead of ln(|gamma(x)|) due to a change made back in 2002 to the __ieee754_gamma_r implementation. This patch fixes that, making all of these functions map too their lgamma equivalents. To fix the underlying bug, the __ieee754_gamma functions have been changed to return gamma(x), removing the _r variants as those are no longer necessary. Their names have been changed to __ieee754_tgamma to avoid potential confusion from users. Now that the __ieee754_tgamma functions return the correctly signed value, the tgamma functions have been modified to use them. libm.a now exposes the following gamma functions: ln(|gamma(x)|): __ieee754_lgamma_r __ieee754_lgammaf_r lgamma lgamma_r gamma gamma_r lgammaf lgammaf_r gammaf gammaf_r lgammal (on machines where long double is double) gamma(x): __ieee754_tgamma __ieee754_tgammaf tgamma tgammaf tgammal (on machines where long double is double) Additional aliases for any of the above functions can be added if necessary; in particular, I'm not sure if we need to include __ieee754_gamma*_r functions (which would return ln(|(gamma(x)|). Signed-off-by: Keith Packard <keithp@keithp.com> ---- v2: Switch commit message to ASCII
2020-09-05 00:25:27 +08:00
double __ieee754_tgamma(x)
double x;
import newlib-2000-02-17 snapshot
2000-02-18 03:39:52 +08:00
#endif
{
libm: Fix 'gamma' and 'gammaf' functions. Clean up other gamma code. [v2] The current gamma, gamma_r, gammaf and gammaf_r functions return |gamma(x)| instead of ln(|gamma(x)|) due to a change made back in 2002 to the __ieee754_gamma_r implementation. This patch fixes that, making all of these functions map too their lgamma equivalents. To fix the underlying bug, the __ieee754_gamma functions have been changed to return gamma(x), removing the _r variants as those are no longer necessary. Their names have been changed to __ieee754_tgamma to avoid potential confusion from users. Now that the __ieee754_tgamma functions return the correctly signed value, the tgamma functions have been modified to use them. libm.a now exposes the following gamma functions: ln(|gamma(x)|): __ieee754_lgamma_r __ieee754_lgammaf_r lgamma lgamma_r gamma gamma_r lgammaf lgammaf_r gammaf gammaf_r lgammal (on machines where long double is double) gamma(x): __ieee754_tgamma __ieee754_tgammaf tgamma tgammaf tgammal (on machines where long double is double) Additional aliases for any of the above functions can be added if necessary; in particular, I'm not sure if we need to include __ieee754_gamma*_r functions (which would return ln(|(gamma(x)|). Signed-off-by: Keith Packard <keithp@keithp.com> ---- v2: Switch commit message to ASCII
2020-09-05 00:25:27 +08:00
int signgam_local;
double y = __ieee754_exp(__ieee754_lgamma_r(x, &signgam_local));
if (signgam_local < 0)
y = -y;
return y;
import newlib-2000-02-17 snapshot
2000-02-18 03:39:52 +08:00
}