math: add exception handling functionality

According to standards SVID and SYSV.
Modified lgamma calling in case when 'signgam' variable should not be used.

Signed-off-by: Waldemar Brodkorb <wbx@uclibc-ng.org>

1 files changed, 48 insertions, 0 deletions

diff --git a/libm/w_tgammaf.c b/libm/w_tgammaf.c
new file mode 100644
index 000000000..812e7d5b6
--- /dev/null
+++ b/libm/w_tgammaf.c
@@ -0,0 +1,48 @@
+/* w_gammaf.c -- float version of w_gamma.c.
+ * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
+ */
+
+/*
+ * ====================================================
+ * 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.
+ * ====================================================
+ */
+
+#include <math.h>
+#include "math_private.h"
+#if __UCLIBC_HAS_FENV__
+#include <errno.h>
+#endif
+
+float
+tgammaf(float x)
+{
+#if __UCLIBC_HAS_FENV__
+	float y = (float) __ieee754_tgamma((double)x);
+
+	if(__builtin_expect (!isfinite (y) || y == 0, 0)
+	   && (isfinite (x) || (isinf (x) && x < 0.0))
+	   && _LIB_VERSION != _IEEE_) {
+	  if (x == (float)0.0)
+	    /* tgammaf pole */
+	    return __kernel_standard_f(x, x, 150);
+	  else if(floorf(x)==x&&x<0.0f)
+	    /* tgammaf domain */
+	    return __kernel_standard_f(x, x, 141);
+	  else if (y == 0)
+	    /* tgammaf underflow */
+	    __set_errno (ERANGE);
+	  else
+	    /* tgammaf overflow */
+	    return __kernel_standard_f(x, x, 140);
+	}
+	return y;
+#else
+	return (float) __ieee754_tgamma((double)x);
+#endif /* __UCLIBC_HAS_FENV__ */
+}