main.go

package main

import (
	"fmt"
	"os"
)

func main() {
	// Create a new CPU instance
	cpu := NewCPU()
	cpu.Debug = true

	// Example program: Calculate factorial of 5
	// This program demonstrates:
	// - Loading immediate values
	// - Arithmetic operations (multiplication)
	// - Conditional jumps
	// - Memory operations
	program := []byte{
		// LOADI R0, 5       ; R0 = 5 (number to calculate factorial of)
		byte(OpLOADI), 0, 0x00, 0x05,

		// LOADI R1, 1       ; R1 = 1 (result accumulator)
		byte(OpLOADI), 1, 0x00, 0x01,

		// LOADI R2, 1       ; R2 = 1 (decrement value)
		byte(OpLOADI), 2, 0x00, 0x01,

		// loop: (address 0x000C)
		// MUL R1, R1, R0    ; R1 = R1 * R0
		byte(OpMUL), 1, 1, 0,

		// SUB R0, R0, R2    ; R0 = R0 - 1
		byte(OpSUB), 0, 0, 2,

		// JZ R0, end        ; if R0 == 0, jump to end (address 0x001C)
		byte(OpJZ), 0, 0x00, 0x1C,

		// JMP loop          ; jump to loop (address 0x000C)
		byte(OpJMP), 0x00, 0x0C, 0x00,

		// end: (address 0x001C)
		// STORE R1, 0x1000  ; Store result at memory address 0x1000
		byte(OpSTORE), 1, 0x10, 0x00,

		// HALT
		byte(OpHALT), 0, 0, 0,
	}

	// Load the program into memory
	cpu.LoadProgram(program)

	fmt.Println("=== Go Micro ISA Emulator ===")
	fmt.Println("\nExample Program: Calculate 5!")
	fmt.Println("\nExecution trace:")
	fmt.Println("--------------------------------------------------")

	// Run the program
	err := cpu.Run()
	if err != nil {
		fmt.Printf("Error during execution: %v\n", err)
		os.Exit(1)
	}

	fmt.Println("--------------------------------------------------")
	fmt.Println("\nExecution completed successfully!")
	fmt.Println()

	// Display final register state
	cpu.DumpRegisters()

	// Read and display the result from memory
	result := cpu.ReadMemory32(0x1000)

	fmt.Printf("\nResult stored at memory[0x1000]: %d\n", result)
	fmt.Printf("Expected: 120 (5! = 5 × 4 × 3 × 2 × 1)\n")
}