Sorry if this is a bit off topic, but I think there are SAM users who
have experience with MGT's GDOS and G+DOS for ZX Spectrum.
I need to implement (in assembler) two file operations:
- Read and overwrite any 1-KiB block of a file.
- Read and write text lines sequentally.
G+DOS does not provide hooks or routines for these operations, so they
have to be implemented ad hoc. I know Andy Wright's Beta DOS included
support for serial and random access files, but there's no disassembly
available. I've searched the Microhobby magazine, which included many
articles on GDOS and G+DOS, but there's nothing about this issue. I
still have to finish searching the Format magazine.
At the moment I'm studying the G+DOS disassembly, trying to identify the
required low-level routines.
I wonder if anybody has tinkered with this before and could help with an
example code or any information.