ajp166 at bellatlantic.net
Sun Nov 13 20:10:27 CST 2005
>Subject: Re: semi-homemade micro
> From: woodelf <bfranchuk at jetnet.ab.ca>
> Date: Sun, 13 Nov 2005 17:19:15 -0700
> To: General Discussion: On-Topic and Off-Topic Posts <cctalk at classiccmp.org>
>>What do you mean by "Well what about them?"?
>Tell me more about them! Non 8 bit word length computers.
I think there is a 22bit forth machine out there and ofcourse people
have done FPGA PDP10 and I also heard once someone doing an 18bit
>All my small C stuff is stored safe in my bitbucket. It has too many
>8080 design gotya's to generate code for the cpu design I have now.
>I don't have register to regsister addressing and indexing from the
And that stopped you? really I have a SmallC compiler that produced
ok 8080 code. By OK it's as good as an 8080 can do.
>Out here all the junk is dead PC's. :(
Thats largely what we have here these days. However 386 and 486
board have nice cache rams some TTL and the like. That and I find
>>Want to try an emulation project? take a 8048 or 49, strap EA
>>(uses external rom then) and write a program to make port 0 and
>>some latches and stuff on the bus port look like a version of
>>your favorite CPU of any word length. Sure it will be slow
>>(8049 @11mhz run instructions at 1.3us) but different! hang
>>ram rom and IO even front pannel on the emulation and you have
>>anything you can imagine and fit in 4k or eprom and 128bytes
>>of internal ram (8049). Those 8048s and 49s are common and
>>easily found in keyboards (LK201 has the faster better 8051!)
>>and is a cool old cpu to work with.
>That is a nice idea!
Everyone has done the PC emulating whatever. Why not take a single
chip micro and use that to emulate another micro as hardware? Same
idea maybe slow but for a lot of things speed is not the whole world.
I did it on paper for PDP8 and it was possible using an 11mhz 8049 to
come within 1/10 the speed of a real 8. I guess a 36bit machine could
be done as well (though really slow.). Also a front pannel could be
programmed into it as well (maybe a speed hit). Any cpu that gets
an instruction from memory and then executes it can be emulated that
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