patch-2.4.6 linux/arch/mips64/math-emu/dp_div.c

• Lines: 161
• Date: Mon Jul 2 13:56:40 2001
• Orig file: v2.4.5/linux/arch/mips64/math-emu/dp_div.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.4.5/linux/arch/mips64/math-emu/dp_div.c linux/arch/mips64/math-emu/dp_div.c
@@ -0,0 +1,160 @@
+/* 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"
+
+ieee754dp ieee754dp_div(ieee754dp x, ieee754dp y)
+{
+	COMPXDP;
+	COMPYDP;
+
+	CLEARCX;
+
+	EXPLODEXDP;
+	EXPLODEYDP;
+
+	switch (CLPAIR(xc, yc)) {
+	case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_SNAN):
+		return ieee754dp_nanxcpt(ieee754dp_bestnan(x, y), "div", x,
+					 y);
+
+	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_SNAN):
+	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_SNAN):
+	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_SNAN):
+	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_SNAN):
+	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_SNAN):
+		return ieee754dp_nanxcpt(y, "div", x, y);
+
+	case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_QNAN):
+	case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_ZERO):
+	case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_NORM):
+	case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_DNORM):
+	case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_INF):
+		return ieee754dp_nanxcpt(x, "div", x, y);
+
+	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_QNAN):
+		return ieee754dp_bestnan(x, y);
+
+	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_QNAN):
+	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_QNAN):
+	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_QNAN):
+	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_QNAN):
+		return y;
+
+	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_ZERO):
+	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_NORM):
+	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_DNORM):
+	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_INF):
+		return x;
+
+
+		/* Infinity handeling 
+		 */
+
+	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_INF):
+		SETCX(IEEE754_INVALID_OPERATION);
+		return ieee754dp_xcpt(ieee754dp_indef(), "div", x, y);
+
+	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_INF):
+	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_INF):
+	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_INF):
+		return ieee754dp_zero(xs ^ ys);
+
+	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_ZERO):
+	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_NORM):
+	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_DNORM):
+		return ieee754dp_inf(xs ^ ys);
+
+		/* Zero handeling 
+		 */
+
+	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO):
+		SETCX(IEEE754_INVALID_OPERATION);
+		return ieee754dp_xcpt(ieee754dp_indef(), "div", x, y);
+
+	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO):
+	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO):
+		SETCX(IEEE754_ZERO_DIVIDE);
+		return ieee754dp_xcpt(ieee754dp_inf(xs ^ ys), "div", x, y);
+
+	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_NORM):
+	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_DNORM):
+		return ieee754dp_zero(xs == ys ? 0 : 1);
+
+	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM):
+		DPDNORMX;
+
+	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_DNORM):
+		DPDNORMY;
+		break;
+
+	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_NORM):
+		DPDNORMX;
+		break;
+
+	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_NORM):
+		break;
+	}
+	assert(xm & DP_HIDDEN_BIT);
+	assert(ym & DP_HIDDEN_BIT);
+
+	/* provide rounding space */
+	xm <<= 3;
+	ym <<= 3;
+
+	{
+		/* now the dirty work */
+
+		unsigned long long rm = 0;
+		int re = xe - ye;
+		unsigned long long bm;
+
+		for (bm = DP_MBIT(DP_MBITS + 2); bm; bm >>= 1) {
+			if (xm >= ym) {
+				xm -= ym;
+				rm |= bm;
+				if (xm == 0)
+					break;
+			}
+			xm <<= 1;
+		}
+		rm <<= 1;
+		if (xm)
+			rm |= 1;	/* have remainder, set sticky */
+
+		assert(rm);
+
+		/* normalise rm to rounding precision ?
+		 */
+		while ((rm >> (DP_MBITS + 3)) == 0) {
+			rm <<= 1;
+			re--;
+		}
+
+		DPNORMRET2(xs == ys ? 0 : 1, re, rm, "div", x, y);
+	}
+}