Chip8

A chip8 emulator.

Chip8 is a kind of assembly language for a long-gone architecture. This plugin runs games written using the chip8 instructions. The plugin works as a ViewerPlugin for the ".ch8" file extension. It quickly became the easiest system to write an emulator for, due to its low graphic resolution (64x32) and reduced I/O (a 16-key keyboard).

The HP48 community quickly wrote an emulator, and then enhanced the system capabilities to get higher resolution (128x64), scrolling, bigger sprites and fonts, etc. That new "virtual" system was named SChip (for Super-Chip).

The chip8 spec: http://members.aol.com/autismuk/chip8/chip8def.htm

The rockbox Chip8 plugin shares its code with the SVision-8 standalone emulator. You can find more information on Chip-8 and SChip on the SVision-8 page.

Programs

The Chip8 programs are available from various places and none of them seems to have distribution restrictions. The SChip programs were mainly made by the HP48 community and were posted on various HP48 newsgroups and archives.

The archives GAMES.zip and SGAMES.zip contain these programs, together with any source files or documentation that came with them, and with the key mappings that make most of them playable on RockBox.

Search http://www.google.com/search?q=HP48+games Google for more

Keys

The original Chip8 key layout looks like:

1	2	3	C
4	5	6	D
7	8	9	E
A	0	B	F

The default key mapping between Chip8 keys and RockBox keys is as follows:

Chip8 key	0	1	2	3	4	5	6	7	8	9	A	B	C	D	E	F
Recorder		F1	Up	F3	Left	Play	Right	F2	Down	On
Ondio			Up		Left	Mode	Right		Down
iRiver			Up		Left	Select	Right		Down

Unfortunately, some games use keys that are not accessible through the default key mapping. To solve this, one may put a ".c8k" file with the same name as the original program which contains new key mappings (for BLINKY.ch8, one writes a BLINKY.c8k file). That c8k file contains 16 characters describing the mapping from the Chip8 keyboard to the default key mapping (that way, several Chip8 keys can be pressed using only one RockBox key). For example, a file containing the single line:

0122458469ABCDE5

would correspond to the following non-default mappings: 3->2 (up) 6->8 (down) 7->4 (left) 8->6 (right)

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