how to generate opcode map

[savic78]

I`m quite uncertain if the following is possible and
would greatly appreciate your help/suggestions(or if
you know someone that could help me) on this one

I`ll keep it as simple as i can so here it goes...
I`m about to disassemble the z80 binary file of the
following configuration

* a z80 based PLC.
* with the cpu board based on a zilog z84c 008 cpu,
with z84c 4008 series I/O and z84c 3008 timer
counter...

- How to tell the code from data without the opcode
map once i`ve disassembled the EPROM contents?

- how could i obtain/generate/create the opcode map?

- how could i tell if the EPROM 27c256-12f1 has an
interpreter in it(or if it was programmed in pure
assembly)? since there are two srams on board (32k
each)


i know this seems a bit too much but thanx for taking the
time to read it...
Cheers!

 

[zeitghost]

You could look on the web for a z80 disassembler program...

z80 is reasonably easy to disassemble by eye, but it takes a loooooooooooooooooooooooooooooooong time.

As to whether it's an iterpreter or hand coded assembler, the programming style would be a giveaway.

Having at one time disassembled CP/M, you could tell it was written in a higher level language (PL/M).

 

[zeitghost]

The opcode map would be included in a Z80 datasheet. Try looking on Zilog's site, or google for Z80 +pdf or some such.

 

[savic78]

Thanx for the advice.
Looking at the disassmbled code, which approach would you suggest? Any ideas how to start? I have an Spectrum simulator with debugger, showing the execution of code segment around the command being executed step by step. Any ideas how this might be of help.
I have the complete instruction set from zilog, but only in mnemonics, no real codes(which is what i would need)...
Thanx once again mate.
Cheers

 

[zeitghost]

Try this:

http://www.angelfire.com/art2/unicorndreams/msx/Z80R800.html

There's an opcode map page.

http://www.angelfire.com/art2/unicorndreams/msx/Z80R800C.html

 

[savic78]

Thank you so much!
This will really help me a lot!
Best wishes mate!

 

[zeitghost]

Glad to help.