add directory gnu

gnu/glibc/glibc-1.03/math/bsd/common_source/floor.c

@@ -0,0 +1,126 @@
+/*
+ * Copyright (c) 1985 Regents of the University of California.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted provided
+ * that: (1) source distributions retain this entire copyright notice and
+ * comment, and (2) distributions including binaries display the following
+ * acknowledgement:  ``This product includes software developed by the
+ * University of California, Berkeley and its contributors'' in the
+ * documentation or other materials provided with the distribution and in
+ * all advertising materials mentioning features or use of this software.
+ * Neither the name of the University nor the names of its contributors may
+ * be used to endorse or promote products derived from this software without
+ * specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ */
+
+#ifndef lint
+static char sccsid[] = "@(#)floor.c	5.7 (Berkeley) 10/9/90";
+#endif /* not lint */
+
+#include "mathimpl.h"
+
+vc(L, 4503599627370496.0E0 ,0000,5c00,0000,0000, 55, 1.0) /* 2**55 */
+
+ic(L, 4503599627370496.0E0, 52, 1.0)			  /* 2**52 */
+
+#ifdef vccast
+#define	L	vccast(L)
+#endif
+
+
+double ceil();
+double floor();
+
+/*
+ * floor(x) := the largest integer no larger than x;
+ * ceil(x) := -floor(-x), for all real x.
+ *
+ * Note: Inexact will be signaled if x is not an integer, as is
+ *	customary for IEEE 754.  No other signal can be emitted.
+ */
+double
+floor(x)
+double x;
+{
+	double y;
+
+	if (
+#if !defined(vax)&&!defined(tahoe)
+		x != x ||	/* NaN */
+#endif	/* !defined(vax)&&!defined(tahoe) */
+		x >= L)		/* already an even integer */
+		return x;
+	else if (x < (double)0)
+		return -ceil(-x);
+	else {			/* now 0 <= x < L */
+		y = L+x;		/* destructive store must be forced */
+		y -= L;			/* an integer, and |x-y| < 1 */
+		return x < y ? y-(double)1 : y;
+	}
+}
+
+double
+ceil(x)
+double x;
+{
+	double y;
+
+	if (
+#if !defined(vax)&&!defined(tahoe)
+		x != x ||	/* NaN */
+#endif	/* !defined(vax)&&!defined(tahoe) */
+		x >= L)		/* already an even integer */
+		return x;
+	else if (x < (double)0)
+		return -floor(-x);
+	else {			/* now 0 <= x < L */
+		y = L+x;		/* destructive store must be forced */
+		y -= L;			/* an integer, and |x-y| < 1 */
+		return x > y ? y+(double)1 : y;
+	}
+}
+
+#ifndef national			/* rint() is in ./NATIONAL/support.s */
+/*
+ * algorithm for rint(x) in pseudo-pascal form ...
+ *
+ * real rint(x): real x;
+ *	... delivers integer nearest x in direction of prevailing rounding
+ *	... mode
+ * const	L = (last consecutive integer)/2
+ * 	  = 2**55; for VAX D
+ * 	  = 2**52; for IEEE 754 Double
+ * real	s,t;
+ * begin
+ * 	if x != x then return x;		... NaN
+ * 	if |x| >= L then return x;		... already an integer
+ * 	s := copysign(L,x);
+ * 	t := x + s;				... = (x+s) rounded to integer
+ * 	return t - s
+ * end;
+ *
+ * Note: Inexact will be signaled if x is not an integer, as is
+ *	customary for IEEE 754.  No other signal can be emitted.
+ */
+double
+__rint(x)
+double x;
+{
+	double s,t;
+	const double one = 1.0;
+
+#if !defined(vax)&&!defined(tahoe)
+	if (x != x)				/* NaN */
+		return (x);
+#endif	/* !defined(vax)&&!defined(tahoe) */
+	if (copysign(x,one) >= L)		/* already an integer */
+	    return (x);
+	s = copysign(L,x);
+	t = x + s;				/* x+s rounded to integer */
+	return (t - s);
+}
+#endif	/* not national */