Fix for MUL instruction on the v850

* sim/v850/simops.c (Multiply64): Properly test if we need to
	negate either of the operands.

	* sim/testsuite/v850/mul.cgs: New test.

sim/testsuite/v850/mul.cgs

@@ -0,0 +1,15 @@
+# v850e mul
+# mach: v850e
+# as(v850e): -mv850e
+
+	.include "testutils.inc"
+
+# Trivial regression test for incorrect sign bit handling in mul
+
+	seti	-10, r1
+	seti 	2, r2
+	mul	r1, r2, r3
+	reg	r2, -20
+	reg	r3, -1
+
+	pass

sim/v850/simops.c

@@ -339,10 +339,10 @@ Multiply64 (int sign, unsigned long op0)
 	  
       sign = (op0 ^ op1) & 0x80000000;
 	  
-      if (((signed long) op0) < 0)
+      if (op0 & 0x80000000)
 	op0 = - op0;
 	  
-      if (((signed long) op1) < 0)
+      if (op1 & 0x80000000)
 	op1 = - op1;
     }