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

• Lines: 175
• Date: Fri Apr 13 20:26:07 2001
• Orig file: v2.4.3/linux/arch/mips/math-emu/sp_mul.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.4.3/linux/arch/mips/math-emu/sp_mul.c linux/arch/mips/math-emu/sp_mul.c
@@ -0,0 +1,174 @@
+/* IEEE754 floating point arithmetic
+ * single precision
+ */
+/*
+ * 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 "ieee754sp.h"
+
+ieee754sp ieee754sp_mul(ieee754sp x, ieee754sp y)
+{
+	COMPXSP;
+	COMPYSP;
+
+	CLEARCX;
+
+	EXPLODEXSP;
+	EXPLODEYSP;
+
+	switch (CLPAIR(xc, yc)) {
+	case CLPAIR(IEEE754_CLASS_SNAN, IEEE754_CLASS_SNAN):
+		return ieee754sp_nanxcpt(ieee754sp_bestnan(x, y), "mul", 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 ieee754sp_nanxcpt(y, "mul", 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 ieee754sp_nanxcpt(x, "mul", x, y);
+
+	case CLPAIR(IEEE754_CLASS_QNAN, IEEE754_CLASS_QNAN):
+		return ieee754sp_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_ZERO):
+	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_INF):
+		SETCX(IEEE754_INVALID_OPERATION);
+		return ieee754sp_xcpt(ieee754sp_indef(), "mul", x, y);
+
+	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_INF):
+	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_INF):
+	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_NORM):
+	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_DNORM):
+	case CLPAIR(IEEE754_CLASS_INF, IEEE754_CLASS_INF):
+		return ieee754sp_inf(xs ^ ys);
+
+	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_ZERO):
+	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_NORM):
+	case CLPAIR(IEEE754_CLASS_ZERO, IEEE754_CLASS_DNORM):
+	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_ZERO):
+	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO):
+		return ieee754sp_zero(xs ^ ys);
+
+
+	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_DNORM):
+		SPDNORMX;
+
+	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_DNORM):
+		SPDNORMY;
+		break;
+
+	case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_NORM):
+		SPDNORMX;
+		break;
+
+	case CLPAIR(IEEE754_CLASS_NORM, IEEE754_CLASS_NORM):
+		break;
+	}
+	/* rm = xm * ym, re = xe+ye basicly */
+	assert(xm & SP_HIDDEN_BIT);
+	assert(ym & SP_HIDDEN_BIT);
+
+	{
+		int re = xe + ye;
+		int rs = xs ^ ys;
+		unsigned rm;
+
+		/* shunt to top of word */
+		xm <<= 32 - (SP_MBITS + 1);
+		ym <<= 32 - (SP_MBITS + 1);
+
+		/* multiply 32bits xm,ym to give high 32bits rm with stickness
+		 */
+		{
+			unsigned short lxm = xm & 0xffff;
+			unsigned short hxm = xm >> 16;
+			unsigned short lym = ym & 0xffff;
+			unsigned short hym = ym >> 16;
+			unsigned lrm;
+			unsigned hrm;
+
+			lrm = lxm * lym;	/* 16 * 16 => 32 */
+			hrm = hxm * hym;	/* 16 * 16 => 32 */
+
+			{
+				unsigned t = lxm * hym;	/* 16 * 16 => 32 */
+				{
+					unsigned at = lrm + (t << 16);
+					hrm += at < lrm;
+					lrm = at;
+				}
+				hrm = hrm + (t >> 16);
+			}
+
+			{
+				unsigned t = hxm * lym;	/* 16 * 16 => 32 */
+				{
+					unsigned at = lrm + (t << 16);
+					hrm += at < lrm;
+					lrm = at;
+				}
+				hrm = hrm + (t >> 16);
+			}
+			rm = hrm | (lrm != 0);
+		}
+
+		/*
+		 * sticky shift down to normal rounding precision
+		 */
+		if ((int) rm < 0) {
+			rm = (rm >> (32 - (SP_MBITS + 1 + 3))) |
+			    ((rm << (SP_MBITS + 1 + 3)) != 0);
+			re++;
+		} else {
+			rm = (rm >> (32 - (SP_MBITS + 1 + 3 + 1))) |
+			    ((rm << (SP_MBITS + 1 + 3 + 1)) != 0);
+		}
+		assert(rm & (SP_HIDDEN_BIT << 3));
+
+		SPNORMRET2(rs, re, rm, "mul", x, y);
+	}
+}