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-rw-r--r--libm/w_tgamma.c47
1 files changed, 47 insertions, 0 deletions
diff --git a/libm/w_tgamma.c b/libm/w_tgamma.c
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+/* @(#)w_gamma.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 gamma(double x)
+ * Return the logarithm of the Gamma function of x or the Gamma function of x,
+ * depending on the library mode.
+ */
+
+#include <math.h>
+#include "math_private.h"
+#if __UCLIBC_HAS_FENV__
+#include <errno.h>
+#endif
+
+double
+tgamma(double x)
+{
+#if __UCLIBC_HAS_FENV__
+ double y = __ieee754_tgamma(x);
+
+ if(__builtin_expect (!isfinite (y) || y == 0, 0)
+ && (isfinite (x) || (isinf (x) && x < 0.0))
+ && _LIB_VERSION != _IEEE_) {
+ if (x == 0.0)
+ return __kernel_standard(x,x,50); /* tgamma pole */
+ else if(floor(x)==x&&x<0.0)
+ return __kernel_standard(x,x,41); /* tgamma domain */
+ else if (y == 0)
+ __set_errno (ERANGE); /* tgamma underflow */
+ else
+ return __kernel_standard(x,x,40); /* tgamma overflow */
+ }
+ return y;
+#else
+ return __ieee754_tgamma(x);
+#endif
+}
+libm_hidden_def(tgamma);