Source · Code · disassembly

Gyaraga: commented and compilable Galaga source

Neidermeier, Glenn. 2026. “Gyaraga: commented and compilable Galaga source.” Commit 248be0d.

Cite as
neiderm/arcade
Original
https://github.com/neiderm/arcade
Pinned
neiderm/arcade @ 248be0d9d80e04cf24ec5eaa1a2b50aa2f90795f
Accessed
2026-10-21
Licence
none stated
Credit
Glenn Neidermeier's commented Z80 source for Galaga, which reassembles into the program ROMs; labels and comments quoted in galaga claims are his.
Notes
galag/galagao_ASxxx/rom0/*.s. The README targets "Namco rev. B" (MAME's `galaga` set) and says MAME runs the rebuilt ROMs with no SHA errors. The repo also holds a C translation and ROM files; the atlas reads only the assembly.

Cited on

Claims (2)

Galaga awards extra fighters at a first and a second score set by DIP switches, and with some settings again at every interval after the second, the interval being the second score: one setting gives 20,000, 70,000, and every 70,000 points. The three switches index one of two 8-entry tables, picked by bit 2 of the starting-fighter setting. In the first, five settings repeat, two award only the first two scores, and one awards none; in the second, every first score is 30,000, three settings repeat, four award at most the first two, and one awards none. The source reassembles MAME's galaga set, Namco rev. B.galag/galagao_ASxxx/rom0/gg1-4.s L1995–2008galag/galagao_ASxxx/rom0/gg1-4.s L2010–2036galag/galagao_ASxxx/rom0/gg1-4.s L2529–2541galag/galagao_ASxxx/rom0/game_ctrl.s L265–267galag/galagao_ASxxx/rom0/game_ctrl.s L1196–1213README.md L16Code
Every fourth stage of Galaga is a challenging stage: at each stage's start stg_init_splash adds 1 to the stage counter and stores (counter + 1) mod 4, and a 0 there marks a challenge, so the counter values 3, 7, 11, … bring one.galag/galagao_ASxxx/rom0/task_man.s L178–202galag/galagao_ASxxx/rom0/gg1-3.s L1443Code