Oddly the Zip files I found none had a manual...??
Then again I was looking for a TXT or DOC and it was HTML..
Oddly neither Herbs note or the HTML explain why H(val) or
HIGH (VAL) does not behave as they are documented.
As a result I'll do the mask and shift as that was easy to implement and
compatible with assemblers on the CP/M systems and under MyZ80 sim. I
do that as my collection of CP/M machines is both large and frequently in
use.? Code portability is fairly important to me as I'm supporting
8080/8085/z80/Z180/Z280 systems and CP/M 1.4 though CPM3(cpm+).
Of course I don't expect the 8080/8085 machines to run Z80 code but
producing using suitable assembler is something I have done before.
This takes me back to the early 80s when, if the floppy format (or size)
wasn't the issue, the text and assembler formats were.? CP/M in 1980
suffered from?portability issues.? Back then Z80 source could be in not
less than 4 formats extended 8080(intel) style opcodes, TDL opcodes
that were Intel 8080 like but different, Zilogs' manual, and?at least
three Z80 assemblers that all varied for syntax and pseudo ops.
So all this makes sense as to purpose the original plan was build
a generic BIOS without any FAT filesystem for uSD, based on
your work for the uSD handler and the Z80MC as the foundation to
side step hardware build.??Its also pretty slick Z80 build as it allows
for banked lower memory and three IO.??
The target is to modify one of my three Epson PX-8s with uSD as mass storage
to replace and be both larger and faster storage than the slow microcassette
that had failed in that one.? I've done it with CF but that is a bit more complex
hardware, larger, and uses more power.? ?The upside is the way to "install"
the device code in the software (BIOS) as transient (not part of the cold boot
image) was well developed by others and simple to implement.
Allison
