From 597cb9abed201793a88fc67942dc56d6e451b039 Mon Sep 17 00:00:00 2001
From: Eduard Urbach <admin@akyoto.dev>
Date: Mon, 24 Jun 2024 14:14:07 +0200
Subject: [PATCH] Implemented addition

---
 examples/hello/hello.q        |  7 +++++--
 src/build/Function.go         | 10 ++++++++++
 src/build/arch/x64/Add.go     | 18 ++++++++++++++++++
 src/build/asm/Assembler.go    | 27 ++++++++++++++++++---------
 src/build/asm/Instructions.go | 11 +++++++++++
 src/build/asm/Mnemonic.go     | 28 ++++++++++++++++------------
 6 files changed, 78 insertions(+), 23 deletions(-)
 create mode 100644 src/build/arch/x64/Add.go

diff --git a/examples/hello/hello.q b/examples/hello/hello.q
index a9ef287..126c5b5 100644
--- a/examples/hello/hello.q
+++ b/examples/hello/hello.q
@@ -5,8 +5,11 @@ main() {
 hello() {
 	write := 1
 	stdout := 1
-	address := 4194305
-	length := 3
+	address := 4194304
+	length := 0
+
+	address += 1
+	length += 3
 
 	loop {
 		syscall(write, stdout, address, length)
diff --git a/src/build/Function.go b/src/build/Function.go
index dfce655..2e82577 100644
--- a/src/build/Function.go
+++ b/src/build/Function.go
@@ -113,6 +113,16 @@ func (f *Function) CompileInstruction(line token.List) error {
 		return f.CompileFunctionCall(expr)
 	}
 
+	if expr.Token.Kind == token.Operator {
+		switch expr.Token.Text() {
+		case "+=":
+			name := expr.Children[0].Token.Text()
+			number, _ := strconv.Atoi(expr.Children[1].Token.Text())
+			f.Assembler.AddRegisterNumber(f.Variables[name].Register, uint64(number))
+			return nil
+		}
+	}
+
 	return errors.New(&errors.InvalidInstruction{Instruction: expr.Token.Text()}, f.File, expr.Token.Position)
 }
 
diff --git a/src/build/arch/x64/Add.go b/src/build/arch/x64/Add.go
new file mode 100644
index 0000000..234142b
--- /dev/null
+++ b/src/build/arch/x64/Add.go
@@ -0,0 +1,18 @@
+package x64
+
+import "git.akyoto.dev/cli/q/src/build/cpu"
+
+// AddRegNum8 adds a byte to the given register.
+func AddRegNum8(code []byte, destination cpu.Register, number uint8) []byte {
+	if destination >= 8 {
+		code = append(code, REX(0, 0, 0, 1))
+		destination -= 8
+	}
+
+	return append(
+		code,
+		0x83,
+		ModRM(0b11, 0b000, byte(destination)),
+		byte(number),
+	)
+}
diff --git a/src/build/asm/Assembler.go b/src/build/asm/Assembler.go
index f14ca7c..5eb7b2b 100644
--- a/src/build/asm/Assembler.go
+++ b/src/build/asm/Assembler.go
@@ -27,21 +27,15 @@ func (a *Assembler) Finalize() ([]byte, []byte) {
 
 	for _, x := range a.Instructions {
 		switch x.Mnemonic {
-		case MOVE:
+		case ADD:
 			switch operands := x.Data.(type) {
 			case *RegisterNumber:
-				code = x64.MoveRegNum32(code, operands.Register, uint32(operands.Number))
+				code = x64.AddRegNum8(code, operands.Register, uint8(operands.Number))
 
 			case *RegisterRegister:
-				code = x64.MoveRegReg64(code, operands.Destination, operands.Source)
+				// code = x64.AddRegReg64(code, operands.Destination, operands.Source)
 			}
 
-		case RETURN:
-			code = x64.Return(code)
-
-		case SYSCALL:
-			code = x64.Syscall(code)
-
 		case CALL:
 			code = x64.Call(code, 0x00_00_00_00)
 			size := 4
@@ -77,6 +71,21 @@ func (a *Assembler) Finalize() ([]byte, []byte) {
 		case LABEL:
 			labels[x.Data.(*Label).Name] = Address(len(code))
 
+		case MOVE:
+			switch operands := x.Data.(type) {
+			case *RegisterNumber:
+				code = x64.MoveRegNum32(code, operands.Register, uint32(operands.Number))
+
+			case *RegisterRegister:
+				code = x64.MoveRegReg64(code, operands.Destination, operands.Source)
+			}
+
+		case RETURN:
+			code = x64.Return(code)
+
+		case SYSCALL:
+			code = x64.Syscall(code)
+
 		default:
 			panic("Unknown mnemonic: " + x.Mnemonic.String())
 		}
diff --git a/src/build/asm/Instructions.go b/src/build/asm/Instructions.go
index 3662595..091b9d4 100644
--- a/src/build/asm/Instructions.go
+++ b/src/build/asm/Instructions.go
@@ -2,6 +2,17 @@ package asm
 
 import "git.akyoto.dev/cli/q/src/build/cpu"
 
+// AddRegisterNumber adds a number to the given register.
+func (a *Assembler) AddRegisterNumber(reg cpu.Register, number uint64) {
+	a.Instructions = append(a.Instructions, Instruction{
+		Mnemonic: ADD,
+		Data: &RegisterNumber{
+			Register: reg,
+			Number:   number,
+		},
+	})
+}
+
 // MoveRegisterNumber moves a number into the given register.
 func (a *Assembler) MoveRegisterNumber(reg cpu.Register, number uint64) {
 	a.Instructions = append(a.Instructions, Instruction{
diff --git a/src/build/asm/Mnemonic.go b/src/build/asm/Mnemonic.go
index a711a0b..55f1dba 100644
--- a/src/build/asm/Mnemonic.go
+++ b/src/build/asm/Mnemonic.go
@@ -4,17 +4,30 @@ type Mnemonic uint8
 
 const (
 	NONE Mnemonic = iota
+	ADD
+	CALL
+	JUMP
+	LABEL
 	MOVE
 	RETURN
 	SYSCALL
-	LABEL
-	CALL
-	JUMP
 )
 
 // String returns a human readable version.
 func (m Mnemonic) String() string {
 	switch m {
+	case ADD:
+		return "add"
+
+	case CALL:
+		return "call"
+
+	case JUMP:
+		return "jump"
+
+	case LABEL:
+		return "label"
+
 	case MOVE:
 		return "move"
 
@@ -23,15 +36,6 @@ func (m Mnemonic) String() string {
 
 	case SYSCALL:
 		return "syscall"
-
-	case LABEL:
-		return "label"
-
-	case CALL:
-		return "call"
-
-	case JUMP:
-		return "jump"
 	}
 
 	return "NONE"