Implemented register to register instructions

src/build/arch/x64/Move.go

@@ -1,13 +1,43 @@
 package x64
 
+import "git.akyoto.dev/cli/q/src/build/cpu"
+
 // MoveRegNum32 moves a 32 bit integer into the given register.
-func MoveRegNum32(code []byte, register uint8, number uint32) []byte {
+func MoveRegNum32(code []byte, destination cpu.Register, number uint32) []byte {
+	if destination >= 8 {
+		code = append(code, REX(0, 0, 0, 1))
+		destination -= 8
+	}
+
 	return append(
 		code,
-		0xb8+register,
+		0xb8+byte(destination),
 		byte(number),
 		byte(number>>8),
 		byte(number>>16),
 		byte(number>>24),
 	)
 }
+
+// MoveRegReg64 moves a register value into another register.
+func MoveRegReg64(code []byte, destination cpu.Register, source cpu.Register) []byte {
+	r := byte(0) // Extension to the "reg" field in ModRM.
+	b := byte(0) // Extension to the "rm" field in ModRM or the SIB base (r8 up to r15 use this).
+
+	if source >= 8 {
+		r = 1
+		source -= 8
+	}
+
+	if destination >= 8 {
+		b = 1
+		destination -= 8
+	}
+
+	return append(
+		code,
+		REX(1, r, 0, b),
+		0x89,
+		ModRM(0b11, byte(source), byte(destination)),
+	)
+}