From b6d7f66def2235f27791b7b6bf5ddd38ea325416 Mon Sep 17 00:00:00 2001
From: Ian Gulliver
 <flamingcow@flamingcow-mba-m1.flamingcow.tv.beta.tailscale.net>
Date: Sun, 14 Nov 2021 20:37:33 -1000
Subject: [PATCH] Common call and startup code

---
 main.go | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/main.go b/main.go
index 8790cf6..54edfc7 100644
--- a/main.go
+++ b/main.go
@@ -32,7 +32,7 @@ type Instruction struct {
 }
 
 type State struct {
-	Error   error
+	Error error
 
 	FunctionByteCode [][]byte
 	FunctionIndex    int64
@@ -81,18 +81,14 @@ var OpHandlers = map[uint32]OpHandler{
 }
 
 func NewState(functionByteCode [][]byte) *State {
-	stackFrame := &StackFrame{}
-
 	return &State{
 		FunctionByteCode: functionByteCode,
-		Stack: []*StackFrame{
-			stackFrame,
-		},
-		StackFrame: stackFrame,
 	}
 }
 
 func (state *State) Execute() {
+	state.call(0)
+
 	for len(state.Stack) > 0 && state.Error == nil {
 		fnc := state.FunctionByteCode[state.FunctionIndex]
 		start := state.InstructionIndex * InstructionBytes
@@ -169,13 +165,18 @@ func (state *State) NoOp(instr *Instruction) {
 
 func (state *State) Call(instr *Instruction) {
 	fmt.Printf("Call\n")
+	in := state.ReadSigned(&instr.Operand1)
+	state.call(in)
+}
+
+func (state *State) call(functionOffset int64) {
 	stackFrame := &StackFrame{
-		PreviousFunctionIndex: state.FunctionIndex,
+		PreviousFunctionIndex:    state.FunctionIndex,
 		PreviousInstructionIndex: state.InstructionIndex,
 	}
 	state.Stack = append(state.Stack, stackFrame)
 	state.StackFrame = stackFrame
-	state.FunctionIndex += state.ReadSigned(&instr.Operand1)
+	state.FunctionIndex += functionOffset
 	state.InstructionIndex = 0
 }