git @ Cat's Eye Technologies SITU-SOL / 0.1-2015.0731

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SITU-SOL is a programming environment for 6502-based computers that was written by hand during RetroChallenge 07/2015.

For more information, see the Bootstrap Zero blog (you might want to go to its archive and read the posts in chronological order.)

Supporting tools

This repository contains the following supporting tools, written in BASIC:

  • binloader, the first version of the simulated bit-entering facility, used in the warm-up
  • frontpanel, the improved version of the front-panel simulator, used to enter SITU-MON

BASIC sources for these are in src; the tokenized PRG files are in bin.

Note that these programs begin writing to memory at $8100, which is normally inside the memory range that BASIC will also use — thus you are in danger of BASIC overwriting what you enter with its own variable data. So, to safely run either of these programs, you should do something like this:

POKE 56,128:NEW

Memory images

  • situ-mon is a PRG file containing a dump of what memory $8100-$81FF looked like just after SITU-MON was entered and fixed. You can run it from BASIC immediate mode like so:

    LOAD "SITU-MON",8,1
    SYS 33024
  • situ-sol is a PRG file containing a dump of what memory $8100-$8520 looked like just after SITU-SOL was entered and fixed. It also includes SITU-MON — because SITU-SOL calls routines from it — and 256 bytes of almost-unused code between $8200 and $82FF.

    It can be started from BASIC immediate mode like so:

    LOAD "SITU-SOL",8,1
    POKE 2304,0:SYS 33830

    But! There is no symbal table. (The POKE 2304,0 is to stop SITU-SOL from mistakenly behaving as if there's a symbal table at that address, in case that byte isn't zero.) You may wish to load a symbal table first, but I haven't got one handy, yet.

Other things

This repository might, at some point, also contain text files containing disassembled machine code that was entered.