add mux, demux, rom

sim/gate.lua

@@ -86,6 +86,16 @@ function Gate.getdata(gate)
 	return gate.data
 end
 
+function Gate.getcdata(gate, i)
+	assert(i>=0 and i<gate.c.data_size)
+	return gate.c.data[i]
+end
+
+function Gate.setcdata(gate, i, v)
+	assert(i>=0 and i<gate.c.data_size)
+	gate.c.data[i] = v
+end
+
 function Gate.getportisrising(gate, index)
 	return Port.isrising(gate.ports[index])
 end