diff --git a/architecture.md b/architecture.md
index 245aca6..8adea3d 100644
--- a/architecture.md
+++ b/architecture.md
@@ -7,7 +7,7 @@ tt Programming Language Backend Architecture
 
 # Architecture
 
-AST --> Type Checking --> TAST --> IR Emission --> TTIR --> Codegen --> TTASM --> Emit --> FASM -> Binary
+AST --> Type Checking --> TAST --> IR Emission --> TTIR --> Codegen --> ASM --> Emit --> FASM -> Binary
 
 TTIR: TT Intermediate Representation is the Representation that the AST gets turned into. This will be mostly be used for optimissing and abstracting away from Assembly
 TAST: Typed Ast
diff --git a/asm/amd64/amd64.go b/asm/amd64/amd64.go
index 1a9d2df..527942a 100644
--- a/asm/amd64/amd64.go
+++ b/asm/amd64/amd64.go
@@ -5,6 +5,15 @@ import (
 	"strings"
 )
 
+var callConvArgs map[int]Register = map[int]Register{
+	1: DI,
+	2: SI,
+	3: DX,
+	4: CX,
+	5: R8,
+	6: R9,
+}
+
 type Program struct {
 	Functions    []Function
 	MainFunction *Function
@@ -169,6 +178,12 @@ type Register int
 
 const (
 	AX Register = iota
+	CX
+	DX
+	DI
+	SI
+	R8
+	R9
 	R10
 	R11
 
diff --git a/ast/ast.go b/ast/ast.go
index aaa1fb0..8e86db8 100644
--- a/ast/ast.go
+++ b/ast/ast.go
@@ -52,17 +52,35 @@ func (p *Program) String() string {
 	return builder.String()
 }
 
+type Type string
+
+type Argument struct {
+	Name string
+	Type Type
+}
+
 type FunctionDeclaration struct {
 	Token token.Token // The token.FN
 	Body  Expression
 	Name  string
+	Args  []Argument
+}
+
+func ArgsToString(args []Argument) string {
+	var b strings.Builder
+
+	for _, arg := range args {
+		b.WriteString(fmt.Sprintf("%s %s,", arg.Name, arg.Type))
+	}
+
+	return b.String()
 }
 
 func (fd *FunctionDeclaration) declarationNode()     {}
 func (fd *FunctionDeclaration) TokenLiteral() string { return fd.Token.Literal }
 func (fd *FunctionDeclaration) Tok() token.Token     { return fd.Token }
 func (fd *FunctionDeclaration) String() string {
-	return fmt.Sprintf("fn %v() = %v;", fd.Name, fd.Body.String())
+	return fmt.Sprintf("fn %v(%v) = %v;", fd.Name, ArgsToString(fd.Args), fd.Body.String())
 }
 
 // Represents a Expression that we failed to parse
@@ -209,7 +227,7 @@ func (ie *IfExpression) String() string {
 type VariableDeclaration struct {
 	Token                  token.Token // The Identifier token
 	InitializingExpression Expression
-	Type                   string
+	Type                   Type
 	Identifier             string
 }
 
diff --git a/lexer/lexer.go b/lexer/lexer.go
index 9e3095a..1e50dbc 100644
--- a/lexer/lexer.go
+++ b/lexer/lexer.go
@@ -63,6 +63,8 @@ func (l *Lexer) NextToken() token.Token {
 	tok.Loc = l.loc()
 
 	switch l.ch {
+	case ',':
+		tok = l.newToken(token.Comma)
 	case ';':
 		tok = l.newToken(token.Semicolon)
 	case ':':
diff --git a/parser/parser.go b/parser/parser.go
index 7b6c56c..fea2462 100644
--- a/parser/parser.go
+++ b/parser/parser.go
@@ -178,6 +178,38 @@ func (p *Parser) ParseProgram() *ast.Program {
 	}
 }
 
+func (p *Parser) parseType() (t ast.Type, ok bool) {
+	if ok, _ := p.expect(token.Ident); !ok {
+		return "", false
+	}
+
+	return ast.Type(p.curToken.Literal), true
+}
+
+func (p *Parser) parseArgumentList() ([]ast.Argument, bool) {
+	args := []ast.Argument{}
+
+	for p.peekTokenIs(token.Ident) {
+		p.nextToken()
+		name := p.curToken.Literal
+		p.nextToken()
+		t, ok := p.parseType()
+
+		if !ok {
+			return args, false
+		}
+
+		args = append(args, ast.Argument{Type: t, Name: name})
+
+		if !p.peekTokenIs(token.Comma) {
+			break
+		}
+		p.nextToken()
+	}
+
+	return args, true
+}
+
 func (p *Parser) parseDeclaration() ast.Declaration {
 	if ok, _ := p.expect(token.Fn); !ok {
 		return nil
@@ -191,6 +223,13 @@ func (p *Parser) parseDeclaration() ast.Declaration {
 	if ok, _ := p.expectPeek(token.OpenParen); !ok {
 		return nil
 	}
+
+	args, ok := p.parseArgumentList()
+
+	if !ok {
+		return nil
+	}
+
 	if ok, _ := p.expectPeek(token.CloseParen); !ok {
 		return nil
 	}
@@ -208,6 +247,7 @@ func (p *Parser) parseDeclaration() ast.Declaration {
 		Token: tok,
 		Name:  name,
 		Body:  expr,
+		Args:  args,
 	}
 }
 
@@ -371,7 +411,7 @@ func (p *Parser) parseVariableDeclaration() ast.Expression {
 
 	if p.peekTokenIs(token.Ident) {
 		p.nextToken()
-		variable.Type = p.curToken.Literal
+		variable.Type = ast.Type(p.curToken.Literal)
 	}
 
 	if ok, errExpr := p.expectPeek(token.Equal); !ok {
diff --git a/tast/tast.go b/tast/tast.go
index eea1203..d0a079b 100644
--- a/tast/tast.go
+++ b/tast/tast.go
@@ -52,10 +52,16 @@ func (p *Program) String() string {
 	return builder.String()
 }
 
+type Argument struct {
+	Name string
+	Type types.Type
+}
+
 type FunctionDeclaration struct {
 	Token      token.Token // The token.FN
 	Body       Expression
 	Name       string
+	Args       []Argument
 	ReturnType types.Type
 }
 
diff --git a/test.tt b/test.tt
index 8bce7bd..8d848d6 100644
--- a/test.tt
+++ b/test.tt
@@ -1,9 +1,13 @@
 fn main() = {
     hi := 4;
 
-    if hi == 4 in
+    if hi == 4 {
+        test2 := 3;
         hi = 0 
-    else hi = 1;
+    }
+    else {
+        hi = 1
+    };
 
-    hi
+    test2
 };
diff --git a/token/token.go b/token/token.go
index 111638a..eb236b4 100644
--- a/token/token.go
+++ b/token/token.go
@@ -33,6 +33,7 @@ const (
 
 	Semicolon  TokenType = ";"
 	Colon      TokenType = ":"
+	Comma      TokenType = ","
 	Equal      TokenType = "="
 	OpenParen  TokenType = "("
 	CloseParen TokenType = ")"
diff --git a/typechecker/check.go b/typechecker/check.go
index d3f5acc..35f73d0 100644
--- a/typechecker/check.go
+++ b/typechecker/check.go
@@ -26,6 +26,11 @@ func (c *Checker) error(t token.Token, format string, args ...any) error {
 }
 
 func (c *Checker) CheckProgram(program *ast.Program) (*tast.Program, error) {
+	_, err := VarResolve(program)
+	if err != nil {
+		return nil, err
+	}
+
 	newProgram, err := c.inferTypes(program)
 	if err != nil {
 		return nil, err
diff --git a/typechecker/infer.go b/typechecker/infer.go
index a8fa78a..930b334 100644
--- a/typechecker/infer.go
+++ b/typechecker/infer.go
@@ -30,6 +30,13 @@ func (c *Checker) inferDeclaration(decl ast.Declaration) (tast.Declaration, erro
 	switch decl := decl.(type) {
 	case *ast.FunctionDeclaration:
 		vars := make(Variables)
+		for _, arg := range decl.Args {
+			t, ok := types.From(arg.Type)
+			if !ok {
+				return nil, c.error(decl.Token, "could not find the type %q for argument %q", arg.Type, arg.Name)
+			}
+			vars[arg.Name] = t
+		}
 		body, err := c.inferExpression(vars, decl.Body)
 		c.functionVariables[decl.Name] = vars
 
diff --git a/typechecker/variable_resolution.go b/typechecker/variable_resolution.go
index 9e74e3e..7af48e3 100644
--- a/typechecker/variable_resolution.go
+++ b/typechecker/variable_resolution.go
@@ -29,17 +29,13 @@ func copyScope(s *Scope) Scope {
 		newVars[k] = Var{Name: v.Name, FromCurrentScope: false}
 	}
 
-	return Scope{Variables: newVars}
+	return Scope{Variables: newVars, UniqueId: s.UniqueId}
 }
 
 func (s *Scope) Get(name string) (Var, bool) {
 	v, ok := s.Variables[name]
 
-	if ok {
-		return v, true
-	}
-
-	return Var{}, false
+	return v, ok
 }
 
 func (s *Scope) Set(name string, uniqName string) {
@@ -59,6 +55,18 @@ func (s *Scope) HasInCurrent(name string) bool {
 	return v.FromCurrentScope
 }
 
+func (s *Scope) Uniq(name string) string {
+	uniqName := fmt.Sprintf("%s.%d", name, s.UniqueId)
+	s.UniqueId += 1
+	return uniqName
+}
+
+func (s *Scope) SetUniq(name string) string {
+	uniq := s.Uniq(name)
+	s.Set(name, uniq)
+	return uniq
+}
+
 func VarResolve(p *ast.Program) (map[string]Scope, error) {
 	functionToScope := make(map[string]Scope)
 
@@ -66,6 +74,9 @@ func VarResolve(p *ast.Program) (map[string]Scope, error) {
 		switch d := d.(type) {
 		case *ast.FunctionDeclaration:
 			s := Scope{Variables: make(map[string]Var)}
+			for _, arg := range d.Args {
+				s.SetUniq(arg.Name)
+			}
 			err := VarResolveExpr(&s, d.Body)
 			functionToScope[d.Name] = s
 			if err != nil {
@@ -116,25 +127,25 @@ func VarResolveExpr(s *Scope, e ast.Expression) error {
 			return err
 		}
 
-		err = VarResolveExpr(s, e.Then)
+		thenS := copyScope(s)
+		err = VarResolveExpr(&thenS, e.Then)
 		if err != nil {
 			return err
 		}
 
+		elseS := copyScope(s)
 		if e.Else != nil {
-			err = VarResolveExpr(s, e.Else)
+			err = VarResolveExpr(&elseS, e.Else)
 			if err != nil {
 				return err
 			}
 		}
 	case *ast.VariableDeclaration:
 		if s.HasInCurrent(e.Identifier) {
-			return errorf(e.Token, "variable %q redifinded", e.Identifier)
+			return errorf(e.Token, "variable %q redefined", e.Identifier)
 		}
 
-		uniqName := fmt.Sprintf("%s.%d", e.Identifier, s.UniqueId)
-		s.UniqueId += 1
-		s.Set(e.Identifier, uniqName)
+		s.SetUniq(e.Identifier)
 	case *ast.VariableReference:
 		v, ok := s.Get(e.Identifier)
 		if !ok {
diff --git a/types/types.go b/types/types.go
index 94cd447..6aff11e 100644
--- a/types/types.go
+++ b/types/types.go
@@ -53,7 +53,7 @@ func New(id int64, name string) Type {
 	return typeId
 }
 
-func From(name string) (Type, bool) {
-	t, ok := types[name]
+func From(name ast.Type) (Type, bool) {
+	t, ok := types[string(name)]
 	return t, ok
 }
diff --git a/update.md b/update.md
new file mode 100644
index 0000000..09c0f2d
--- /dev/null
+++ b/update.md
@@ -0,0 +1,15 @@
+# What to check if you updated or added something
+
+- [x] Lexer
+- [x] Parser
+    - [x] AST
+    - [x] TAST
+- [x] Type Checker
+    - [x] Variable Resolution
+    - [x] Infer
+    - [x] Check
+- [ ] TTIR
+- [ ] TTIR Emit
+- [ ] Backends
+    - [ ] Qbe
+    - [ ] Fasm