Totally rework the math library, this time based on the MacOs X

math library (which is itself based on the math lib from FreeBSD).
 -Erik

1 files changed, 44 insertions, 0 deletions

diff --git a/libm/s_logb.c b/libm/s_logb.c
new file mode 100644
index 000000000..7ec1c3696
--- /dev/null
+++ b/libm/s_logb.c
@@ -0,0 +1,44 @@
+#if !defined(__ppc__)
+/* @(#)s_logb.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.
+ * ====================================================
+ */
+
+#if defined(LIBM_SCCS) && !defined(lint)
+static char rcsid[] = "$NetBSD: s_logb.c,v 1.8 1995/05/10 20:47:50 jtc Exp $";
+#endif
+
+/*
+ * double logb(x)
+ * IEEE 754 logb. Included to pass IEEE test suite. Not recommend.
+ * Use ilogb instead.
+ */
+
+#include "math.h"
+#include "math_private.h"
+
+#ifdef __STDC__
+	double logb(double x)
+#else
+	double logb(x)
+	double x;
+#endif
+{
+	int32_t lx,ix;
+	EXTRACT_WORDS(ix,lx,x);
+	ix &= 0x7fffffff;			/* high |x| */
+	if((ix|lx)==0) return -1.0/fabs(x);
+	if(ix>=0x7ff00000) return x*x;
+	if((ix>>=20)==0) 			/* IEEE 754 logb */
+		return -1022.0; 
+	else
+		return (double) (ix-1023); 
+}
+#endif /* !__ppc__ */