NEC v20 and CP/M

[bugman2112]

I have been discussing the NEC processor on another thread. Specifically, I thought I'd ask here about the CP/M emulator by Stephen Hunt (VCPM) that runs using the 8080 emulation code on a NEC v20 processor. I've searched the net and only found two files. VCPM.a86 (uncompiled) and VCPM.CMD (compiled?) There are some instructions in the source code about how to compile but I am unsure how to use the program. Can anyone point me in the direction of some documentation?

 

[SteveH]

Fame at last...

I wrote that sometime back in the late 80s when I was playing with V20s in a number of non-IBM compatible PC type boxes (in particular, the LSI-M4, CAL-PC and LSI-Octopus machines). The .A86 file is the source and the .CMD the compiled program (runs under CP/M-86).

I must admit that I wasn't too hot on documentation (other than comments in the code).:blush:

Anyway, to run the program, just type VCPM (or whatever the compiled program is called) followed by the name of the CP/M-80 program followed by an optional file name. For example, the following command would run WordStar and load the document LETTER.DOC

VCPM WS LETTER.DOC

Unfortunately, I haven't got the V20 support documentation any more, but suspect you'd be able to find a copy on the net. Any questions, just ask.

Steve

 

[bugman2112]

Thanks. It will be interesting to mess around with that. Just curious, do you know how screen addressing controls are handled with this kind of setup? I'm accustomed to using CP/M via a terminal where the communication program uses something like vt52, vt100, etc. emulation.

 

[Chuck(G)]

There were a lot of CP/M emulators, some using the x80 emulation on the V-series chips. Heck, I even wrote one. Versions of 22Nice prior to about 1992 include support for the V-series instructions, as well as software emulation for 8080 and Z80 (you need software emulation for 8080 even if you have a V20, because there was a handful of programs that ran into a bug in the V20 support. JRT Pascal was one).

22Nice implemented several emulation modes, include Kaypro/ADM3 and others. Alternatively, you can elect to use no emulation and use an ANSI.SYS driver.

I've also got a copy of CPMulator, one of the earliest V20 CP/M packages that I know of.

 

[SteveH]

Just curious, do you know how screen addressing controls are handled with this kind of setup?

The program I wrote does nothing special - CP/M-80 BIOS and BDOS calls are simply passed back (with a few exceptions) to the host CP/M-86 calls. However, as Chuck(G) points out, other emulators actually emulate certain types of systems/displays.