I'm trying to find some documentation about R800 CPU that I saw some time ago. It was from this post, at www.z80.info. I downloaded the file R800.ZIP, but I haven't found there the information that I got that day. It just shows now a table with assembler instructions of Z80 and R800.

The document that I saw talked widely about the whole history of R800, and much more things... What happened to that document? Do somebody still have it? I really need it!

Greetings!

If you're Dutch, MCCM has what you want to find . I remember them pages being full of R800 ops and articles about timings, and history as well.

Argf... I'm spanish... There is not such a documentation in english at least?

Then I suggest you'd rely on R800 experts. As for me, I'm totally NO R800 expert, sorry

What is it you're looking for? If it's only history I can't help you, but I do have some other R800 data... (instructions and the lot)

all please!!!

This is what I want to know:

• R800 instruction set (this is the only info that I got)
• A bit of history about R800.
• How R800 (RISC) can be compatible with Z80 (CISC).
• Differences processing data, as R800 is 16 bits but Z80 is 8, while the data bus is still 8 bits.
• Architecture of R800: how is the processor internally, number of registers and bits of them (16 bits I guess), ALU, etc...
• How the R800 manages integer and floating point operations.
• I/O codes of R800: BCD, ASCII, etc... (I guess that it will be the very same as Z80)

This is almost everything that I need to know.

Well, what I have mainly is some general Turbo-R I made recently. Unfortunately it includes almost none of the info you're looking for I wrote some small texts on maily instructions and their Z80 counterparts plus the calculation of the timing differences. That, plus some general info on cpu switching etc... I'd send it to you by email, but it looks like you already have that info... Sorry...

You should ask GuyveR800. He knows all this.

Quote:

You should ask GuyveR800. He knows all this.

Well Guyver himself answered me some time ago to the question of "How R800 (RISC) can be compatible with Z80 (CISC).".

What I don't manage to understand is why the excellent documentation of the R800 at z80.info has changed. Do somebody still have the old documentation of this site?

Arfh! This document would be great, but it is in dutch: http://www.funet.fi/pub/msx/docs/hwmodsetc/r800.pdf

Hmm, the r800.pdf contains little information on the backgrounds (history) of the R800, I don't know if it is what you're looking for...

I don't think this is what you are looking for... It just has some info on the R800 processor, some of it incorrect I might add... Like snout said, nothing about the history of the R800. If it would make you feel any better, I could make up a nice story though It seemed to work fine in the Genic days

Well... actually, I already finished my "Introduction to MSX (Z80) Structure" work for university. So I managed to get some info from some Dutch documents and from old forums posts of the MRC