patch-2.4.19 linux-2.4.19/arch/mips/math-emu/sp_tint.c

• Lines: 92
• Date: Fri Aug 2 17:39:43 2002
• Orig file: linux-2.4.18/arch/mips/math-emu/sp_tint.c
• Orig date: Fri Apr 13 20:26:07 2001

diff -urN linux-2.4.18/arch/mips/math-emu/sp_tint.c linux-2.4.19/arch/mips/math-emu/sp_tint.c
@@ -35,38 +35,74 @@
 	CLEARCX;
 
 	EXPLODEXSP;
+	FLUSHXSP;
 
 	switch (xc) {
 	case IEEE754_CLASS_SNAN:
 	case IEEE754_CLASS_QNAN:
-		SETCX(IEEE754_INVALID_OPERATION);
-		return ieee754si_xcpt(ieee754si_indef(), "fixsp", x);
 	case IEEE754_CLASS_INF:
-		SETCX(IEEE754_OVERFLOW);
-		return ieee754si_xcpt(ieee754si_indef(), "fixsp", x);
+		SETCX(IEEE754_INVALID_OPERATION);
+		return ieee754si_xcpt(ieee754si_indef(), "sp_tint", x);
 	case IEEE754_CLASS_ZERO:
 		return 0;
-	case IEEE754_CLASS_DNORM:	/* much to small */
-		SETCX(IEEE754_UNDERFLOW);
-		return ieee754si_xcpt(0, "fixsp", x);
+	case IEEE754_CLASS_DNORM:
 	case IEEE754_CLASS_NORM:
 		break;
 	}
 	if (xe >= 31) {
-		SETCX(IEEE754_OVERFLOW);
-		return ieee754si_xcpt(ieee754si_indef(), "fix", x);
-	}
-	if (xe < 0) {
-		SETCX(IEEE754_UNDERFLOW);
-		return ieee754si_xcpt(0, "fix", x);
+		/* look for valid corner case */
+		if (xe == 31 && xs && xm == SP_HIDDEN_BIT)
+			return -2147483648;
+		/* Set invalid. We will only use overflow for floating
+		   point overflow */
+		SETCX(IEEE754_INVALID_OPERATION);
+		return ieee754si_xcpt(ieee754si_indef(), "sp_tint", x);
 	}
 	/* oh gawd */
 	if (xe > SP_MBITS) {
 		xm <<= xe - SP_MBITS;
-	} else if (xe < SP_MBITS) {
-		/* XXX no rounding 
-		 */
-		xm >>= SP_MBITS - xe;
+	} else {
+		unsigned long residue;
+		int round;
+		int sticky;
+		int odd;
+
+		if (xe < -1) {
+			residue = xm;
+			round = 0;
+			sticky = residue != 0;
+			xm = 0;
+		}
+		else {
+			residue = xm << (32 - SP_MBITS + xe);
+			round = (residue >> 31) != 0;
+			sticky = (residue << 1) != 0;
+			xm >>= SP_MBITS - xe;
+		}
+		odd = (xm & 0x1) != 0x0;
+		switch (ieee754_csr.rm) {
+		case IEEE754_RN:
+			if (round && (sticky || odd))
+				xm++;
+			break;
+		case IEEE754_RZ:
+			break;
+		case IEEE754_RU:	/* toward +Infinity */
+			if ((round || sticky) && !xs)
+				xm++;
+			break;
+		case IEEE754_RD:	/* toward -Infinity */
+			if ((round || sticky) && xs)
+				xm++;
+			break;
+		}
+		if ((xm >> 31) != 0) {
+			/* This can happen after rounding */
+			SETCX(IEEE754_INVALID_OPERATION);
+			return ieee754si_xcpt(ieee754si_indef(), "sp_tint", x);
+		}
+		if (round || sticky)
+			SETCX(IEEE754_INEXACT);
 	}
 	if (xs)
 		return -xm;