Implemented dynamic array indices

src/x64/StoreDynamicOffset.go

@@ -0,0 +1,130 @@
+package x64
+
+import (
+	"encoding/binary"
+
+	"git.akyoto.dev/cli/q/src/cpu"
+)
+
+// StoreDynamicOffsetNumber stores a number into the memory address at `destination` with a register offset.
+func StoreDynamicOffsetNumber(code []byte, destination cpu.Register, offset cpu.Register, length byte, number int) []byte {
+	var (
+		w      = byte(0)
+		r      = byte(0)
+		x      = byte(0)
+		b      = byte(0)
+		opCode = byte(0xC7)
+		mod    = AddressMemory
+	)
+
+	if length == 1 {
+		opCode = 0xC6
+	}
+
+	if offset == RSP {
+		tmp := offset
+		offset = destination
+		destination = tmp
+	}
+
+	if length == 8 {
+		w = 1
+	}
+
+	if offset > 0b111 {
+		x = 1
+		offset &= 0b111
+	}
+
+	if destination > 0b111 {
+		b = 1
+		destination &= 0b111
+	}
+
+	if destination == RBP || destination == R13 {
+		mod = AddressMemoryOffset8
+	}
+
+	if length == 2 {
+		code = append(code, 0x66)
+	}
+
+	code = append(code, REX(w, r, x, b))
+	code = append(code, opCode)
+	code = append(code, ModRM(mod, 0b000, 0b100))
+	code = append(code, SIB(Scale1, byte(offset), byte(destination)))
+
+	if mod == AddressMemoryOffset8 {
+		code = append(code, 0x00)
+	}
+
+	switch length {
+	case 8, 4:
+		return binary.LittleEndian.AppendUint32(code, uint32(number))
+
+	case 2:
+		return binary.LittleEndian.AppendUint16(code, uint16(number))
+	}
+
+	return append(code, byte(number))
+}
+
+// StoreDynamicOffsetRegister stores the contents of the `source` register into the memory address at `destination` with a register offset.
+func StoreDynamicOffsetRegister(code []byte, destination cpu.Register, offset cpu.Register, length byte, source cpu.Register) []byte {
+	var (
+		w      = byte(0)
+		r      = byte(0)
+		x      = byte(0)
+		b      = byte(0)
+		opCode = byte(0x89)
+		mod    = AddressMemory
+	)
+
+	if length == 1 {
+		opCode = 0x88
+	}
+
+	if offset == RSP {
+		tmp := offset
+		offset = destination
+		destination = tmp
+	}
+
+	if length == 8 {
+		w = 1
+	}
+
+	if source > 0b111 {
+		r = 1
+		source &= 0b111
+	}
+
+	if offset > 0b111 {
+		x = 1
+		offset &= 0b111
+	}
+
+	if destination > 0b111 {
+		b = 1
+		destination &= 0b111
+	}
+
+	if destination == RBP || destination == R13 {
+		mod = AddressMemoryOffset8
+	}
+
+	if length == 2 {
+		code = append(code, 0x66)
+	}
+
+	code = append(code, REX(w, r, x, b))
+	code = append(code, opCode)
+	code = append(code, ModRM(mod, byte(source), 0b100))
+	code = append(code, SIB(Scale1, byte(offset), byte(destination)))
+
+	if mod == AddressMemoryOffset8 {
+		code = append(code, 0x00)
+	}
+
+	return code
+}