Improved build performance

src/x64/Move.go

@@ -0,0 +1,13 @@
+package x64
+
+// MoveRegNum32 moves a 32 bit integer into the given register.
+func MoveRegNum32(code []byte, register uint8, number uint32) []byte {
+	return append(
+		code,
+		0xb8+register,
+		byte(number),
+		byte(number>>8),
+		byte(number>>16),
+		byte(number>>24),
+	)
+}