steve@slovax.UUCP (Steve Cook) (02/26/88)
A while back I bought some cga mode games programs to play with
on my xt clone. I have a generic hercules compatible graphics
card so I downloaded the simcga & hgcibm progs from bitnet. I
haven't been able to get either of them to work on the games, most
notably Accolade Golf.
The computer hangs up with the bell stuck on , I have to cycle the
power - reset doesn't work. My clone uses a Nec V20 chip. Is the
problem caused by the V20, the bios, simcga/hgcibm, or do the
cheaper games programs do weird things with the displays?? If I bought
an ega card/monitor would I have problems still (caused by the V20)?
On a similar subject, are there any accelerator boards out there that
will work on a V20 based system?? Since several of the boards replace
the original chip with a jumper to the new board, will this type of
board work? If I replace the motherboard with a newer/faster (286,386)
board will the rest of the cards still work (disk, modem, etc...???)
Whoa is me, obviously I'm not a hardware type. Any semi-informed
opinion is welcome. Thanks
--
Disclaimer: I have no opinions. RDA has a lot. Non-intersecting set.
{psivax,ism780}!logico!slovax!steve : {hplsla,uw-beaver}!tikal!slovax!steve
Steve Cook R & D Associates,3625 Perkins Lane SW
Ithering Blidiot Tacoma,Wa 98499,206-581-1322Geoffrey_Welsh@watmath.waterloo.edu (02/27/88)
The posting asked for a semi-informed reply, and I am definitely qualified to provide that! (B^>) The only compatibility problems in the NEC V20 are caused by its built-in Z80 emulation, which is controlled by a bit in the CPU's FLAGS register. Some software recklessly loads the FLAGS register disregarding Intel's warning about reserved bits. The problem is that, if the bit that NEC has appropriated to enable Z80 emulation is loaded to the wrong value (a 50% chance if you don't pay attention to 8086 programming manuals), the V20 drops into Z80 emulation. Naturally, a Z80 won't make any sense whatsoever of the 8086 instruction set. Murphy's law states that one of the 8086 op codes the V20-cum-Z80 will try to execute will be interpreted as a Z80 "halt & catch fire" instruction ( hence the crash?) As for accelerator cards, if it works with an 8088 (or requires that you remove the 8088 from its socket and place a cable header in its place), it SHOULD work with a V20 (but I have to warn you: I have NOT tried this myself!). Geoff ( watmath!fido!221.171!izot ) AKA "Incompetent Hacker [maxint]" --- ConfMail V3.31 * Origin: The Waterloo Window: WOC's out there? (1:221/171)
pjh@mccc.UUCP (Peter J. Holsberg) (03/01/88)
In article <17145@watmath.waterloo.edu> 221.162.fido!Geoffrey_Welsh@watmath.waterloo.edu writes: | | The posting asked for a semi-informed reply, and I am definitely |qualified to provide that! (B^>) | | The only compatibility problems in the NEC V20 are caused by its |built-in Z80 emulation, which is controlled by a bit in the CPU's FLAGS ^^^ If only that were so! The V20 executes (NOT emulates) 8080 instructions, but not the extended ones that the Z80 has. -- Peter Holsberg UUCP: {rutgers!}princeton!mccc!pjh Technology Division CompuServe: 70240,334 Mercer College GEnie: PJHOLSBERG Trenton, NJ 08690 Voice: 1-609-586-4800
Geoffrey_Welsh@watmath.waterloo.edu (03/03/88)
> From: pjh@mccc.UUCP (Peter J. Holsberg) > Message-ID: <266@mccc.UUCP> > Date: 1 Mar 88 14:57:27 GMT > | The only compatibility problems in the NEC V20 are caused by its > |built-in Z80 emulation, which is controlled by a bit in the CPU's FLAGS > ^^^ > > If only that were so! The V20 executes (NOT emulates) 8080 > instructions, but not the extended ones that the Z80 has. My mistake (obviously). The rumour mill suggests that a V-25 is in the works with full Z80 instruction set. Any confirmations? I get all confused. A V-20 is an 8088 replacement. A V-30 is an 8086 replacement. What's a V-40 (I have it in a turbo-XT clone)? Geoff ( watmath!fido!221.171!izot ) --- ConfMail V3.31 * Origin: The Waterloo Window: WOC's out there? (1:221/171)