Disassembly Examples

Welcome to the Regenerator 2000 examples documentation. These HTML disassemblies are generated directly by Regenerator 2000 and showcase the auto-analysis, layout parity, and modern styling capabilities of our HTML exporter.

Below are the main examples available in this project:

Moving Tubes - Commodore 64

A disassembly of Moving Tubes intro, by Laxity.

Disassembly

• 🔗 c64_moving_tubes_lxt.html

Main takeaways:

• Great source to learn about different techniques (intermediate level).
• Clean code.
• How a SID player works: the SID player was disassembled in detail.
• Raster IRQ techniques
• Different tips & tricks:
  • Convert JMP into BIT, and other self-modifying code techniques.
  • Double call with JSR to next line
  • Background logo color in sync with SID music
  • Sine table for scrolling speed
  • Variable-width chars in scroller

Source:

• CSDB: Moving Tubes (Laxity Intro #145)
• The original intro was packed. The disassembly contains the unpacked version. Unpacked with Unp64).

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Lode Runner - Commodore PET

A disassembly of Lode Runner clone for Commodore PET, by jimbo.

Disassembly

• 🔗 pet_loderunner.html

Main takeaways:

• Clean code.
• Great place to learn about the PET programming.

Source:

• Itchio: Lode Runner for the PET by jimbo
• Since the game was not packed, this is a good example of how the disassembly looks like without any post-processing.

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Omega Race - VIC-20

A disassembly of the game Omega Race for VIC-20.

Disassembly

• 🔗 vic20_omega_race_cart_generic_a000.html

Main takeaways:

• WIP

Source:

• Omega Race on VIC-20 Cartridges

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Kikstart - Commodore Plus/4

A disassembly of the Commodore Plus/4 motorcycle obstacle course game Kikstart.

Disassembly

• 🔗 plus4_kikstart_8192.html

Main takeaways:

• WIP

Source:

• Kikstart on Plus/4 World

H.E.R.O is Back! - Commodore 128

A disassembly of the Commodore 128 game H.E.R.O is Back, by LC Games.

Disassembly

• 🔗 c128_hero_is_back.html

Main takeaways:

• WIP

Source:

• H.E.R.O Is Back Webapage

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Burnin' Rubber - Commodore 64

A disassembly of the Commodore 64 "Burnin' Rubber" game.

Disassembly

• 🔗 c64_burnin_rubber.html

Main takeaways:

• The code was written in a monitor, not with an assembler. Evidence:
  • Dead code / Dead tables: Although not uncommon to have some dead code / tables in a program, it is a lot more common when using a monitor.
  • There is a .T0400,07FF,2C00 monitor command in the code. Which means " Transfer the bytes from $0400-$07FF to $2C00". Funny thing, that command is at $2C00, which makes sense. The programmer might have typed it at the top-left of the screen.
  • Functions that are split in multiple places, using JMP to connect them.
  • Three NOP opcodes padding at the beginning of some functions. Possibly to remove a possible JSR to a debug routine.
  • Some ZP variables are accessed using the three-byte variant of LDA. E.g.: LDA $F2 translates to AD F2 00 instead of A5 F2
  • Lack of a "clean" high level architecture: for example the main loop is split in multiple places.
• Good place to learn how early C64 games were programmed using a monitor, but not a good place to learn modern best practices.
  • Trivia: It is not possible to add comments when using a monitor, so, the developers might have used other tools, like a notebook, to document the code (that's what I used to do when I was a kid!).

Source:

• TAP file: Burnin' Rubber.tap
• The game was taken from the original TAP source.
• The game was encrypted. Part of the game code was in the loader, and part was in the main program.
• The disassembly contains a single file that includes the decrypted main program with part of the loader code.
• Part of the encrypted code is still present, but not used.
• Run it with: SYS 4752