shrubba / impulse-tracker

Original source code for Impulse Tracker, a music tracker for DOS

Impulse Tracker

Full source code for Impulse Tracker, including sound drivers, network drivers, and some supporting documentation

Pre-Requisite Software

To build Impulse Tracker, you will need:

• Turbo Assembler v4.1

• Turbo Link v3.01

• Borland MAKE v4.0

• A DOS environment

Once you have these, building IT.EXE should be just a single call to MAKE

Sound drivers are build individually via M*.BAT files inside the SoundDrivers subdirectory

Quick File Overview

• IT.ASM: Startup routines

• IT_DISK.ASM: Disk IO Routines. Uses IT_D_*.INC files

• IT_DISPL.ASM: Display routines for the Playback Screen (F5)

• IT_EMS.ASM: EMS memory handling routines

• IT_F.ASM: Collection of functions used by the object model

• IT_FOUR.ASM: Fast Fourier routines. Used by the graphic equalizer (Alt-F12). Not available on all all sound cards

• IT_G.ASM: Global key handler functions

• IT_H.ASM: Help Module (F1)

• IT_I.ASM: Sample list (F3) and Instrument list (F4) module

• IT_K.ASM: Keyboard module

• IT_L.ASM: Information line code

• IT_M.ASM: Main message loop/dispatcher

• IT_MDATA.ASM: Global music variable data

• IT_MMTSR.ASM: Sample compression/decompression routines

• IT_MOUSE.ASM: Mouse handling code

• IT_MSG.ASM: Message editor module (Shift-F9)

• IT_MUSIC.ASM: Module playback code. Also uses IT_M_EFF.INC

• IT_NET.ASM: Network code

• IT_OBJ1.ASM: UI object definitions

• IT_PE.ASM: Pattern Editor module (F2)

• IT_S.ASM: Screen functions, including character generation

• IT_TUTE.ASM: Interactive Tutorial module

• IT_VESA.ASM: VESA code for graphic equalizer

• SWITCH.INC: High level switches for the program

Frequently Asked Questions

Q: "What are all those funny characters in the source code?"

A: I wrote the original source code using DOS characters, with characters drawing borders/boxes in comments in the source code. In the interests of posterity, I have left the code intact as it was.

Q: "Why didn't you use STRUCs or ENUMs" in your ASM source?

A: Simply because I didn't know about them at the time. I wish I did. There's a InternalDocumentation folder that I've included in the repository that details what some of the magic numbers appearing through the code might mean.

Q: "Flow in some functions seems to jump all over the place. Why?"

A: The original code was compatible all the way back to an 8086 machine. 8086 would allow you to do conditional jumps only within +/-128 bytes, so I spent too much time shuffling code around to meet this restriction. When I shifted away from this 8086 restriction, I never went back to update the code that was mutilated by it.

License

BSD 3-clause license can be found in LICENSE.