Most of the resources are in Japanese but Google Translate in Chrome does decent work instantly translating into English. The resources in English are marked.

GMC-4 is cloned from other microcomputers, and its instruction set is compatible with:

• FX-microcomputer R-165
• Tandy Microcomputer Trainer (english)

Links to various resources about GMC-4

• Official magazine issues

  • http://otonanokagaku.net/feature/vol23/index.html
  • http://otonanokagaku.net/magazine/vol24/index.html
  • http://otonanokagaku.net/english/magazine/vol24/index.html (english)

• Review and documentation

  • Programming the Gakken GMC-4 Microcomputer, architecture and instruction set (english)
  • GMC-4 Microcomputer Manual (english)
  • About GMC-4 (introduction, instruction set, simulator, compiler)
  • GMC-4 microcomputer (english)

• Firmware

There are no sources available of the original GMC-4 firmware.

• Hardware

  • Schematic (version 1, version 2)
  • Keypad connector for the loader (upside, downside, schematic)
  • USB loader 1 (assembled, interface board, schematic, port layout, firmware sources, 74HC4051 datasheet)

• Blogs

  • http://blog.nshdot.com/search/label/gmc-4/
  • http://airvariable.asablo.jp/blog/cat/gmc-4/
  • http://100year.cocolog-nifty.com/blog/gmc4/
  • http://www.geocities.jp/yasuho68k/gmc4/ (a bunch of sample programs)
  • http://d.hatena.ne.jp/yasuho/searchdiary?word=%2A%5B4%A5%D3%A5%C3%A5%C8%A5%DE%A5%A4%A5%B3%A5%F3%5D

• Simulators

  • GMC-4 simulator (screenshot)
  • FX-microcomputer R-165 simulator (screenshot)
  • On Android

• Loaders

  • GMC-4 Microcomputer USB loader based on UBW (english)
  • GMC-4 USB loader based on the AVR controller
  • GMC-4 loader based a PIC development board

• Assemblers

  • http://www.musashinodenpa.com/misc/GMC4/
  • http://slashdot.jp/~roto/journal/481254
  • https://github.com/jasperla/gmc4-as/
  • http://fxm.piroyan.com/
  • http://d.hatena.ne.jp/nicotakuya/20090702/1246521731

• Compilers

  • C Compiler
  • BASIC Compiler

• Replications

  • avr-gmc-4 (AVR) (sources)
  • devkitARM (ARM) (screenshot, sources)

• Links collection from the Official Wiki

  • http://www15.atwiki.jp/gmc4/pages/12.html