patch-2.4.4 linux/arch/mips/math-emu/dp_modf.c

• Lines: 81
• Date: Fri Apr 13 20:26:07 2001
• Orig file: v2.4.3/linux/arch/mips/math-emu/dp_modf.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.4.3/linux/arch/mips/math-emu/dp_modf.c linux/arch/mips/math-emu/dp_modf.c
@@ -0,0 +1,80 @@
+/* IEEE754 floating point arithmetic
+ * double precision: common utilities
+ */
+/*
+ * MIPS floating point support
+ * Copyright (C) 1994-2000 Algorithmics Ltd.  All rights reserved.
+ * http://www.algor.co.uk
+ *
+ * ########################################################################
+ *
+ *  This program is free software; you can distribute it and/or modify it
+ *  under the terms of the GNU General Public License (Version 2) as
+ *  published by the Free Software Foundation.
+ *
+ *  This program is distributed in the hope it will be useful, but WITHOUT
+ *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ *  for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with this program; if not, write to the Free Software Foundation, Inc.,
+ *  59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
+ *
+ * ########################################################################
+ */
+
+
+#include "ieee754dp.h"
+
+/* modf function is always exact for a finite number
+*/
+ieee754dp ieee754dp_modf(ieee754dp x, ieee754dp * ip)
+{
+	COMPXDP;
+
+	CLEARCX;
+
+	EXPLODEXDP;
+
+	switch (xc) {
+	case IEEE754_CLASS_SNAN:
+	case IEEE754_CLASS_QNAN:
+	case IEEE754_CLASS_INF:
+	case IEEE754_CLASS_ZERO:
+		*ip = x;
+		return x;
+	case IEEE754_CLASS_DNORM:
+		/* far to small */
+		*ip = ieee754dp_zero(xs);
+		return x;
+	case IEEE754_CLASS_NORM:
+		break;
+	}
+	if (xe < 0) {
+		*ip = ieee754dp_zero(xs);
+		return x;
+	}
+	if (xe >= DP_MBITS) {
+		*ip = x;
+		return ieee754dp_zero(xs);
+	}
+	/* generate ipart mantissa by clearing bottom bits 
+	 */
+	*ip = builddp(xs, xe + DP_EBIAS,
+		      ((xm >> (DP_MBITS - xe)) << (DP_MBITS - xe)) &
+		      ~DP_HIDDEN_BIT);
+
+	/* generate fpart mantissa by clearing top bits
+	 * and normalizing (must be able to normalize)
+	 */
+	xm = (xm << (64 - (DP_MBITS - xe))) >> (64 - (DP_MBITS - xe));
+	if (xm == 0)
+		return ieee754dp_zero(xs);
+
+	while ((xm >> DP_MBITS) == 0) {
+		xm <<= 1;
+		xe--;
+	}
+	return builddp(xs, xe + DP_EBIAS, xm & ~DP_HIDDEN_BIT);
+}