Posted March 16, 2026 by cobour
First of all I did a complete rewrite of the disk access code. I've coma a long way starting with NeonWorld, then A100 and now Hydron.
On NeonWorld I used the standard adf creator tool that came with the Amiga Assembly plugin for VSCode. The game came as a Amiga-standard executable file and a standard DOS disk with a startup-sequence. Easy to adapt for WHDLoad as no special code replacements were needed.
For A100 I chose a different approach. Though I used the adf creator again (resulting in a standard DOS disk) but with a custom bootblock now. I wrote some code to load DOS files with "trackdisk.device". The game code was completely relocatable so it could be placed anywhere in RAM. I used exec's AllocMem to get the RAM the game needs and then loaded the game code into it from inside the bootblock.
But now I did what I always wanted to, do it myself without something provided by the OS, with pure disk DMA. I no longer use the adf creator but write the adf file with my converter tool (written in Java), that converts the graphics etc. into the needed raw formats and gzip's everything. The disk DMA code is small enough to be placed in the bootblock so no OS code is needed. I therefor look for RAM locations myself and overwrite that I need. The bootblock never gives control back to the OS. Just coding the metal directly...