Implemented CMP

Author: cavaliercoder

dispatch.go

@@ -54,7 +54,9 @@ var opcodes = [][]opcode{
 	[]opcode{ /* 0x8... */ },
 	[]opcode{ /* 0x9... */ },
 	[]opcode{ /* 0xA... */ },
-	[]opcode{ /* 0xB... */ },
+	[]opcode{ /* 0xB... */
+		{0xB000, 0xF100, opCmp},
+	},
 	[]opcode{ /* 0xC... */
 		{0xC100, 0xF1F0, opAbcd},
 	},

opb.go

@@ -0,0 +1,24 @@
+package m68k
+
+// opCmp implements CMP (pg. 4-75)
+func opCmp(c *Processor) (t *stepTrace) {
+	t = &stepTrace{
+		addr: c.PC,
+		op:   "cmp",
+		n:    1,
+		sz:   c.op & 0x1c >> 6,
+	}
+	c.PC += 2
+
+	ea := decodeEA(c.op)
+	reg := c.op & 0x0E00 >> 9
+
+	var a, b Int
+	a = NewInt(c.D[reg], int(t.sz))
+	b, t.src, t.err = c.readInt(ea, t.sz)
+
+	a = a.Sub(b)
+	c.SR &= 0xFFFFFFF0
+	c.SR |= a.Status()
+	return
+}