stereo-editor

Stereo Editor: A vintage C-64 SID editor

This is the original source code for the C-64 application "Stereo Editor 1.0" (circa 1989), converted from PETSCII to normal ASCII and lightly edited so that it can be cross-assembled by modern hardware.

Building

The code was originally edited on a Commodore 128 and built using Chris Miller's Buddy Assembler. I've written a compatible, portable cross assembler that the included Makefile uses to build the application on Linux or the Mac (maybe even Windows). You can find that assembler here.

The Makefile can also optionally create a .d64 disk image with all files needed to run the application on an emulator. This requires the c1541 command line tool that is included with the VICE emulator distribution.

Run make to build all changed modules. Output will appear in the obj subdirectory.

make package uses c1541 to generate stereo-editor.d64, also in the obj subdirectory.

make clean simply clears the obj directory in case you want to do a fresh build from scratch.

Running

load "stereo editor",8,1 will load and run Stereo Editor using a fast loader. If the fast loader proves incompatible with whatever drive or virtual drive you're using, try load "slow editor",8,1.

load "midi player",8,1 runs a (possibly unreleased?) application that plays selected SIDs in sequence through a Sequential or Passport MIDI interface. slow player is the non-fastload boot program for that application.

Overview of Source Files

boot.asm is a short program that does nothing but load the bootstrapper/kernal module.

kernal.asm (object file 001) is responsible for loading the rest of the system and also includes a 4K screen I/O and fast DOS kernal that it copies to $e000.

charset.asm (object file 002) and sprites.asm (object file 003) are the bitmapped assets used by the editor.

editor.asm (object file 004) contains the bulk of the code.

archive-builder.asm (object file 012) is loaded on demand to build MSW, SAL, etc. bundles.

words-editor.asm (object file 009) is loaded on demand to edit .wds files.

credit-block-editor.asm (object file 008) is loaded on demand to edit the SID's credits.

key-customizer.asm (object file 005) is loaded on demand to modify command key shortcuts.

midi-player.asm (object file 014) is the alternate MIDI player application discussed above.

settings.asm (object file 007) contains the initial values for application settings

Memory Map

0000-00ff:        Zero page storage
0100-01ff:        CPU stack
0200-03ff:        System storage, IRQ handler, thunks for required kernal ROM APIs
0400-57ff:        Main editor application (src/editor.asm)
5800-59ff:        Credit block for the SID being edited
5a00-5bff:        Settings (persisted to file "007")
5c00-5fff:        General editor module data storage
6000-6fff:        SID or MIDI player code (from file "006" or "013")
7000-bfff:        Music data heap: 3-6 voices plus optional lyrics (up to 20K)
c000-cfff:        Transient application code (words editor, key customizer, archiver, etc.)
d000-d7ff:        Character set (src/charset.asm) or I/O registers (bank switched)
d800-d9ff:        Sprites (src/sprites.asm) or VIC color SRAM (bank switched)
da00-dfff:        Cut and paste buffer or VIC color SRAM plus I/O registers (bank switched)
e000-efff:        Custom kernal (src/kernal.asm)
f000-f3ff:        Kernal general storage (menu management, fast load buffers, etc.)
f400-f7ff:        VIC screen memory
f800-fbff:        Saved screen area
fc00-ffff:        Saved color area