using an FPGA to emulate a vintage computer
in [FPGA]
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From: Abby Brown on 18 Feb 2010 12:37 "Eric Chomko" <pne.chomko(a)comcast.net> wrote in message news:badc12c3-cb2b-4ce9-9543-237d60fc22d5(a)o8g2000vbm.googlegroups.com... > Has anyone created a copy machine of an old system using an > FPGA? I > was wondering if it would be possible to take an entire SWTPC > 6800 and > compile the schematics and have it run on an FPGA board.? > Wouldn't > even have to be the latest Xylinx product, I suspect. Absolutely. There a number of them. This guy has done a PDP-4 and PDP-8, http://homepage.mac.com/dgcx/pdp4x/ http://homepage.mac.com/dgcx/pdp4x/ I am in the process of doing a PDP-1. My background is high performance computers so it is a high performance design. Todays FPGAs and CAD allow a much more agressive implementation than the original designers could afford and with far less effort. The original PDP-1s sold for about $100K in early 1960s' dollars. Mine will cost only a few hundred dollars to build. Those interested in the subject might also be interested in the simh group, http://simh.trailing-edge.com/ which does simulators for legacy computers. Gary
From: Morten Reistad on 18 Feb 2010 16:05 In article <lMmdneY0IJR65-DWnZ2dnUVZ_uKdnZ2d(a)supernews.com>, Abby Brown <abbybrown(a)charter.net> wrote: > >"Eric Chomko" <pne.chomko(a)comcast.net> wrote in message >news:badc12c3-cb2b-4ce9-9543-237d60fc22d5(a)o8g2000vbm.googlegroups.com... >> Has anyone created a copy machine of an old system using an >> FPGA? I >> was wondering if it would be possible to take an entire SWTPC >> 6800 and >> compile the schematics and have it run on an FPGA board.? >> Wouldn't >> even have to be the latest Xylinx product, I suspect. > >Absolutely. There a number of them. This guy has done a PDP-4 >and PDP-8, > > http://homepage.mac.com/dgcx/pdp4x/ > > http://homepage.mac.com/dgcx/pdp4x/ > >I am in the process of doing a PDP-1. My background is high >performance computers so it is a high performance design. Do you pipeline it? Any issues? >Todays FPGAs and CAD allow a much more agressive implementation >than the original designers could afford and with far less >effort. The original PDP-1s sold for about $100K in early >1960s' dollars. Mine will cost only a few hundred dollars to >build. A PDP1 is cool. Please tell when you have a production run. If I have the money, I may shell out for a kit suitable for an economist to assemble. But a PDP6, or a '10 with a modern performance design would be ultracool. >Those interested in the subject might also be interested in the >simh group, > > http://simh.trailing-edge.com/ > >which does simulators for legacy computers. I have used several of these emulators for years. Thank you for your excellent work. -- mrr
From: Abby Brown on 18 Feb 2010 18:57 "Morten Reistad" <first(a)last.name> wrote in message news:emm057-j0a.ln1(a)laptop.reistad.name... > In article <lMmdneY0IJR65-DWnZ2dnUVZ_uKdnZ2d(a)supernews.com>, > Abby Brown <abbybrown(a)charter.net> wrote: >> >>"Eric Chomko" <pne.chomko(a)comcast.net> wrote in message >>news:badc12c3-cb2b-4ce9-9543-237d60fc22d5(a)o8g2000vbm.googlegroups.com... >>> Has anyone created a copy machine of an old system using an >>> FPGA? I .... >>I am in the process of doing a PDP-1. My background is high >>performance computers so it is a high performance design. > > Do you pipeline it? Any issues? The current design is not pipelined. Ultimately, I expect it will be pipelined and latched. > A PDP1 is cool. Please tell when you have a production run. If > I have the money, I may shell out for a kit suitable for an > economist to assemble. I can make the board and chip design available. > But a PDP6, or a '10 with a modern performance design would > be ultracool. That would be a group effort. I have an emotional attachment to PDP-1s. I spent many happy hours playing Spacewar on a PDP-1 and learned to program on it as well. Gary
From: jmfbahciv on 19 Feb 2010 09:10 Abby Brown wrote: > "Eric Chomko" <pne.chomko(a)comcast.net> wrote in message > news:badc12c3-cb2b-4ce9-9543-237d60fc22d5(a)o8g2000vbm.googlegroups.com... >> Has anyone created a copy machine of an old system using an >> FPGA? I >> was wondering if it would be possible to take an entire SWTPC >> 6800 and >> compile the schematics and have it run on an FPGA board.? >> Wouldn't >> even have to be the latest Xylinx product, I suspect. > > Absolutely. There a number of them. This guy has done a PDP-4 > and PDP-8, > > http://homepage.mac.com/dgcx/pdp4x/ > > http://homepage.mac.com/dgcx/pdp4x/ > > I am in the process of doing a PDP-1. My background is high > performance computers so it is a high performance design. > Todays FPGAs and CAD allow a much more agressive implementation > than the original designers could afford and with far less > effort. The original PDP-1s sold for about $100K in early > 1960s' dollars. Mine will cost only a few hundred dollars to > build. > > Those interested in the subject might also be interested in the > simh group, > > http://simh.trailing-edge.com/ > > which does simulators for legacy computers. Re your background is high performance, what do you like best about the PDP-1? (Or haven't you got that far?) /BAH
From: Abby Brown on 21 Feb 2010 13:10
"jmfbahciv" <jmfbahciv(a)aol> wrote in message news:hlm59g2jg9(a)news4.newsguy.com... > Abby Brown wrote: >> "Eric Chomko" <pne.chomko(a)comcast.net> wrote in message >> news:badc12c3-cb2b-4ce9-9543-237d60fc22d5(a)o8g2000vbm.googlegroups.com... >>> Has anyone created a copy machine of an old system using an >>> FPGA? I >>> was wondering if it would be possible to take an entire >>> SWTPC 6800 and >>> compile the schematics and have it run on an FPGA board.? >>> Wouldn't >>> even have to be the latest Xylinx product, I suspect. >> >> Absolutely. There a number of them. This guy has done a >> PDP-4 and PDP-8, >> >> http://homepage.mac.com/dgcx/pdp4x/ >> >> http://homepage.mac.com/dgcx/pdp4x/ >> >> I am in the process of doing a PDP-1. My background is high >> performance computers so it is a high performance design. >> Todays FPGAs and CAD allow a much more agressive >> implementation than the original designers could afford and >> with far less effort. The original PDP-1s sold for about >> $100K in early 1960s' dollars. Mine will cost only a few >> hundred dollars to build. >> >> Those interested in the subject might also be interested in >> the simh group, >> >> http://simh.trailing-edge.com/ >> >> which does simulators for legacy computers. > > Re your background is high performance, what do you like best > about the PDP-1? (Or haven't you got that far?) > > /BAH The best (and worst) is the PDP-1's simplicity. It is easy to implement. For the most part conditionals are decoupled from arithmetic operations. That helps branches, which are always a bottleneck. The single arithmetic register is a bottleneck. Out of order execution, for example, is difficult when almost every instruction accesses the same register. Other the other hand, if you treat memory as registers, which is feasible (there are only 4K words), you can do interesting things with out-of-order. RISC computers, such as ALPHA and MIPS, have compilers that help the hardware by ordering instructions. With legacy software, you cannot do that. For comparison, when I was a DECie, I did the instruction fetch and processing unit for a data flow VAX (never produced, unfortunately). The number and complexity of instructions and the weirdness of a few made high performace difficult. That was one of the reasons DEC developed ALPHA. Gary |