Archive for June, 2012

Floppy support still in progress

June 22nd, 2012

I didn’t totally finished floppy support but I’m pretty sure of one thing fun : JSI used an already existing lib.

They didn’t fully updated it.
They cleaned some stuff (like the BPB table) but not the format data (6 availables while 4 selectable), because code is based on 6 bytes per data
and, according the format defined, at least one is for 5 1/4 floppy.
It was not coded for SMD because a minimun file size is 512k … won’t fit on a 360k 5 1/4 floppy !

I think it also why the code is a total mess LOL

Anyway, another thing which make it hard to re-code is the fact they use the same function to write and read.
It’s a bit value which define the read or write code part of each functions.
I didn’t notice it on the first pass so I missed a lot of things !

Megadrive | Posted by KanedaFr

floppy support is really hard

June 19th, 2012

I ‘m finally working on the Floppy support…
It will help me to debug the floppy drive on my broken SMD

It’s really hard to understand all of the features of the floppy controller.
Even more hard since JSI re-use memory a lot !
Floppy dedicated vars are so shared with others… very difficult to handle this with IDA !

Megadrive | Posted by KanedaFr