package nes

// CPU memory map is:
// +--------------------------------------------------------------------------------------------------+
// | Address range		| Size	| Device															  																|
// +--------------------------------------------------------------------------------------------------+
// | $0000-$07FF		| $0800	| 2 KB internal RAM													  														|
// | $0800-$0FFF		| $0800	| Mirror of $0000-$07FF												  													|
// | $1000-$17FF		| $0800	| Mirror of $0000-$07FF												  													|
// | $1800-1FFF			| $0800 | Mirror of $0000-$07FF												  													|
// | $2000-2007			| $0008 | PPU registers														  															|
// | $2008-$3FFF		| $1FF8	| Mirrors of $2000-$2007 (repeats every 8 bytes)					  							|
// | $4000-4017			| $0018	| APU and I/O registers												  													|
// | $4018-$401F		| $0008 | APU and I/O functionality thats normally disabled (CPU test mode)	  		|
// | $4020-$FFFF		| $BFE0	| Unmapped, available for cartridge									  										|
// | - $6000-$7FFF		| $2000	| Usually cartridge RAM (if present)								 										|
// | - $8000-$FFFF		| $8000 | Usually cartridge ROM (if present)								  									|
// +--------------------------------------------------------------------------------------------------+
// wow i put way too much effort into making that table

func (n *Console) Read(addr uint16) uint8 {
	switch {
	case addr < 0x2000: // internal RAM and mirrors
		return n.RAM[addr&0x7FF]
	case addr < 0x4000: // PPU registers, mirrored every 8 bytes
		return n.PPU.ReadRegister(addr)
	case addr == 0x4016: // controller 1
		return n.controllers[0].read()
	case addr == 0x4017: // controller 2
		return n.controllers[1].read()
	case addr >= 0x4020: // cartridge
		return n.Cart.Mapper.CPURead(addr)
	default:
		return 0
	}
}

func (n *Console) Write(addr uint16, v uint8) {
	switch {
	case addr < 0x2000:
		n.RAM[addr&0x7FF] = v
	case addr < 0x4000:
		n.PPU.WriteRegister(addr, v)
	case addr == 0x4014: // oam dma
		n.oamDMA(v)
	case addr == 0x4016: // strobe is shared by both controllers
		n.controllers[0].setStrobe(v&1 != 0)
		n.controllers[1].setStrobe(v&1 != 0)
	case addr >= 0x4020:
		n.Cart.Mapper.CPUWrite(addr, v)
	}
}