module src/cpu

import bytearray
import src/ram
import src/renderer

/*
The CPU for the Chip8 emulator.
CPU Cycle and Effects:
1. Fetch Opcode
2. Decode Opcode
3. Execute Opcode
4. Update Timers
5. Update Display
6. Wait for next cycle
*/

namespace cpu {
  def run(rom: ByteArray) {r: Renderer}: Unit = {
    // Initialize the RAM
    var ram = makeRam()
    // Load the predefined fontset into the RAM and load the ROM
    ram.init(rom)
    
    // Initialize the CPU registers
    var v: ByteArray = allocate(16) // 16 8-bit registers
    var i: Int = 0 // 16-bit register treat as 12-bit !!!

    var delay: Byte = 0.toByte // Delay timer
    var sound: Byte = 0.toByte // Sound timer

    var pc: Int = 512 // Program counter
    var sp: Byte = 0.toByte // Stack pointer
    var stack: ByteArray = allocate(32) // Stack with 16 levels. Each level is 16-bit that is 2 bytes, so 32 bytes

    // Main loop
    // Fetch, Decode, Execute, Update Timers, Update Display
    r.log("Starting the CPU...")
    r.fill("black")
    // TODO: Implement the main loop with effects
    ()
  }
}