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5673Re: [cosmacelf] Re: creating a cosmacelf simulator in C

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  • Bill Rowe
    Oct 4, 2008
    • 0 Attachment
      That's it and there's a wonderful picture of it with switches and lights.
      http://www.compendiumarcana.com/CDP1802/CC1802.PNG

      I've fallen in love with the arduino which uses the AVR microcomputers instead of the PICs but they offer the same kind of wonderful compactness.
      ----- Original Message -----
      From: J.C. Wren
      To: cosmacelf@yahoogroups.com
      Sent: Saturday, October 04, 2008 12:01 PM
      Subject: Re: [cosmacelf] Re: creating a cosmacelf simulator in C


      http://www.compendiumarcana.com/CDP1802/PIC1802.asm
      Not sure of the currency of it, but Google found it.

      --jc

      On Sat, Oct 4, 2008 at 11:57 AM, Andrew Wasson <andrew@...>wrote:

      > That's right Bill.
      > If I remember correctly it was Kevin Timmerman who created the Pic
      > 1802. I used to have the ASM listing for it. I thought it was a really
      > neat idea.
      >
      > Andrew
      >
      >
      >
      >
      >
      > --- In cosmacelf@yahoogroups.com, "Bill Rowe" <bill_rowe@...> wrote:
      > >
      > > re the PIC version, if you look way back in the message archives to
      > where we were talking about a "Membership Card" single board system,
      > someone had built a tiny replica with 1802 emulation on a chip - I
      > forget the builder and the chip type but I thought it was wonderfully
      > cute.
      > > ----- Original Message -----
      > > From: akshay parelkar
      > > To: cosmacelf@yahoogroups.com
      > > Sent: Friday, October 03, 2008 5:05 PM
      > > Subject: Re: [cosmacelf] Re: creating a cosmacelf simulator in C
      > >
      > >
      > > Thanks a lot for all the tip, suggestions and articles.
      > >
      > > I will now proceed with the project.
      > >
      > > Thanks again
      > >
      > > --- On Fri, 10/3/08, ted_rossin <ted_rossin@...> wrote:
      > > From: ted_rossin <ted_rossin@...>
      > > Subject: [cosmacelf] Re: creating a cosmacelf simulator in C
      > > To: cosmacelf@yahoogroups.com
      > > Date: Friday, October 3, 2008, 11:30 AM
      > >
      > > I just uploaded the source code to my Elf emulator in the
      > >
      > > Files/Simulators folder (TedsElf.zip) . It is in C++ but should give
      > >
      > > you some hints on how to proceed. The source is for a Visual Studio
      > >
      > > project. The real meat is in 1802.cpp and 1802.h. You can find
      > >
      > > programs that will run and instuctions on my web site:
      > >
      > > http://www.geocitie s.com/ted_ rossin/Electroni cs/RCA/RCA. html
      > >
      > > One problem with many of the 1802 emulators that I tried is that
      > >
      > > they are not coded up for real-time operation. They tend to run as
      > >
      > > fast as they can which tends to be much faster than the real machine
      > >
      > > and varies based on processor speed. I use Windows timers to step
      > >
      > > my emulator at a periodic rate (I think every 50ms) for a tunable
      > >
      > > number of steps. This keeps the simulator speed constant across
      > >
      > > multiple machines. I don't have it perfectly tuned up but it does
      > >
      > > run within 10% of my real Elf system.
      > >
      > > The point I'm trying to make is to not make your emulator a giant
      > >
      > > while loop but instead write it such that it is a subroutine that
      > >
      > > maintains the state of the machine so that it can be called once per
      > >
      > > unit of activity. For example, you could model all the machine
      > >
      > > states and call the subroutine once per clock cycle. I choose to do
      > >
      > > it once per instruction but I maintain state as to the number of
      > >
      > > machine cycles executed (2 or 3 per instruction) . Machine cycles
      > >
      > > are 8 clock cycles.
      > >
      > > This also allows you to hook up devices to your emulator such as
      > >
      > > LEDs, keyboards or 1861 video chips.
      > >
      > > Good luck and have fun. I enjoyed the process and am now able to
      > >
      > > develope code for my 1.6 MHz Elf on a 3.0 GHz PC.
      > >
      > > --- In cosmacelf@yahoogrou ps.com, akshay parelkar <va7aax@> wrote:
      > >
      > > >
      > >
      > > > Hi Fans of Cosmac Elfs,
      > >
      > > >
      > >
      > > > I recently discovered this fancy little computer while searchig on
      > >
      > > the web. I dont have a Real Cosmac Elf yet(Have digital ones
      > >
      > > though).
      > >
      > > >
      > >
      > > > Lately, I have been thinking about writing up my own code (in C)
      > >
      > > to simulate the Cosmac elf. I dont expect this project to compete
      > >
      > > with the ones already available, just something with which I can
      > >
      > > undertand more about the 1802 itself and improve and exercise my own
      > >
      > > (rather limited) knowledge of C.
      > >
      > > >
      > >
      > > > Can somebody give some suggestions as to how and where I
      > >
      > > can/should start?
      > >
      > > >
      > >
      > > > Also, another idea rolling in my mind is, Would it be possible to
      > >
      > > build a replica Cosmac Elf based on a PIC or has anyone already done
      > >
      > > this?
      > >
      > > >
      > >
      > > > Thanks,
      > >
      > > >
      > >
      > > > Long live cosmac elfs!
      > >
      > > >
      > >
      > > >
      > >
      > > >
      > >
      > > >
      > >
      > > > [Non-text portions of this message have been removed]
      > >
      > > >
      > >
      > >
      > >
      > >
      > >
      > >
      > >
      > >
      > >
      > >
      > >
      > > [Non-text portions of this message have been removed]
      > >
      > >
      > >
      > >
      > >
      > >
      > >
      >
      > ----------------------------------------------------------
      > >
      > >
      > > No virus found in this incoming message.
      > > Checked by AVG.
      > > Version: 7.5.524 / Virus Database: 270.7.5/1705 - Release Date:
      > 03/10/2008 8:18 AM
      > >
      > >
      > > [Non-text portions of this message have been removed]
      > >
      >
      >
      >
      > ------------------------------------
      >
      > ========================================================
      > Visit the COSMAC ELF website at http://www.cosmacelf.comYahoo! Groups
      > Links
      >
      >
      >

      [Non-text portions of this message have been removed]






      ------------------------------------------------------------------------------


      No virus found in this incoming message.
      Checked by AVG.
      Version: 7.5.524 / Virus Database: 270.7.5/1706 - Release Date: 03/10/2008 6:17 PM


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