Systems Memory Mapping

Work in Progress

This page details how the memory of each supported system is mapped.

NES

Memory map obtained from https://wiki.nesdev.com/w/index.php/CPU_memory_map

Offset	Length	Description	used by RA
$0000	$800	2KB internal RAM	✔
$0800	$800	Mirror of $000-$7FF	✔
$1000	$800	Mirror of $000-$7FF	✔
$1800	$800	Mirror of $000-$7FF	✔
$2000	8	NES PPU registers
$2008	$1FF8	Mirrors of $2000-2007 (repeats every 8 bytes)
$4000	$20	Registers (Mostly APU)
$4020	$1FD	Cartridge Expansion ROM
$6000	$200	SRAM
$8000	$4000	PRG-ROM
$C000	$400	PRG-ROM

Famicom Disk System

SNES

https://en.wikibooks.org/wiki/Super_NES_Programming/SNES_memory_map

N64

https://en.wikibooks.org/wiki/N64_Programming/Memory_mapping

GB

http://gameboy.mongenel.com/dmg/asmmemmap.html

GBC

GBA

https://www.coranac.com/tonc/text/hardware.htm#sec-memory

VirtualBoy

Master System

Source: http://www.codeslinger.co.uk/pages/projects/mastersystem/memory.html

TODO: find a more reliable source.

Offset	Length	Description
0x0C000	0x02000	RAM

MegaDrive (Genesis)

https://en.wikibooks.org/wiki/Genesis_Programming https://wiki.megadrive.org/index.php?title=Main_68k_memory_map see also Jamiras comment here: https://github.com/RetroAchievements/RALibretro/issues/47#issuecomment-455374796

GameGear

Atari 2600

http://www.randomterrain.com/atari-2600-memories-tutorial-andrew-davie-05.html#summary

Offset	Length	Description
0x00080	0x00080	RAM

Atari 7800

Atari Lynx

ColecoVision

NeoGeo Pocket

PCEngine (TurboGrafx16)

PCEngine CD

Arcade

PC-8001 / PC-8801

The memory map is based on the PC-8801 layout¹, but excludes graphics VRAM and extended RAM.

PC-8801

Bank	Offset	Length	Description
0	0x00000	0x10000	Main RAM
1	0x10000	0x1000	Text VRAM

Text VRAM is also known as high-speed RAM, and is used as a main RAM area in some titles.

PC-8001

The entire memory space² is mapped in the PC-8801 main RAM bank, but only RAM is exposed, so most of the mapped space will remain uninitialized.

Offset	Length	Description
0x08000	0x08000	RAM