From: nowhere@never.at   
      
   On 05/04/2023 05:45, muta...@gmail.com wrote:   
      
   >>>>> The intent is to allow the user to zap either CPU type   
   >>>>> onto the FPGA.   
      
   possible, but not even CPUs from one producer share:   
     pin count, pin-layout, BUS-width controls and timing.   
     so they need also different BUS connections (impedance).   
      
   more worse for different manufacturers:   
     IRQ polarity and behavior(might use soft or hard ACK)   
     RESET condition (where and how to start code fetch)   
     and a few more ...   
      
   > I am talking about a general-purpose laptop (which   
   > apparently hasn't been built, but may be possible to   
   > be built).   
   > General purpose meaning I can flash any CPU I want   
   > on it. Or at a minimum, Plasma and 80836:   
      
   > https://opencores.org/projects/zet86   
      
   good luck, hope you know how to use a solder-iron :)   
      
   > I would like to own such a laptop, even though I don't   
   > have an immediate use for such a machine. So that   
   > if I want to run a S/370 (or modified version) in 10   
   > years from now, the machine is ready, I can "just"   
   > start working on the VHDL (or hire someone to do that).   
      
   you could buy an FPGA evaluation kit, I once (1999) tried one to see if   
   my idea for a then new CPU style (the "famous" ALT.OS CPU) would work.   
   It worked, but AMD had a similar idea and penetrated the market before I   
   even finished documentation for my gadget.   
      
   > If I flash an 80386 onto the FPGA, then I expect my   
   > existing 80386 code to work, which uses the "out"   
   > instruction.   
   ...   
   > I didn't say that I wanted a modern computer.   
   > That's why I want to drive a serial port in the first place.   
      
   > Other devices I want to drive are a hard disk, and I'm   
   > willing to do that over serial port too.   
      
   OMG, that's how little Paul think hardware can be treated :)   
   give every pin on all your devices a UART ...   
      
   > If there are other   
   > options, that don't require too much coding, I'm interested   
   > in them as an alternative, but at the end of the day, I'm   
   > happy to drive the keyboard, terminal, modem and hard   
   > disk over serial ports (which I already know how to drive   
   > using "out" instructions).   
      
   none of these devices except modems can be controlled by serial ports.   
      
   > Yes, I know it will be slow.   
   > It was also slow when I used a Commodore 64 with   
   > a floppy disk on serial port.   
      
   C-64 had its very own communication hardware, quite different to PCs.   
   __   
   wolfgang   
      
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