A twist on emulation...

Subject: A twist on emulation... From: "Graham Toal" <gtoal at gtoal.com> Date: Mon, 14 May 2007 14:18:26 -0500 To: cctech at classiccmp.org I took a pdp15 compiler and a pdp15 emulator this weekend and hacked them together in a way such that the compiler outputs what looks like a windows executable that you can simply run like a normal DOS (x86 DOS, not the other one) command-line program. The emulator is embedded in the .EXE along with the pdp15 code. It lets you have the experience of writing in an early 1970's language for the PDP15 much as if you'd been on the machine itself, but without the hassle of managing an emulator. The language is an early version of Imp, which predates the more common Imp77 or Imp80 versions; in fact it is actually much closer to the original Atlas Autocode than it is to the final versions of Imp. A significant feature of the language is that it allows embedded PDP15 assembly language. Unfortunately I don't have a document describing the early language, though I do have a few example programs you could look at to pick it up from. The windows-ported binary of the compiler is here: http://history.dcs.ed.ac.uk/archive/languages/imp-pdp15/windows_port/ see the readme.txt for manual installation instructions. I'll put up the source of the system and some working example imp15 source files in a day or two. meanwhile related files are: http://history.dcs.ed.ac.uk/archive/languages/imp-pdp15/EMULATOR.txt http://history.dcs.ed.ac.uk/archive/languages/imp-pdp15/CompilerOutput.htm http://history.dcs.ed.ac.uk/archive/languages/imp-pdp15/hdcomp-emul.i15.html http://history.dcs.ed.ac.uk/archive/languages/imp-pdp15/takeon.i15.html http://history.dcs.ed.ac.uk/archive/languages/imp-pdp15/gram.txt http://history.dcs.ed.ac.uk/archive/languages/imp-pdp15/IMP15SYS.TXT a trivial hello world program looks like this: %begin %print %text 'Welcome to the 1970''s!' %end %of %programme save it as hello.i15 and then execute these commands: imp15 hello link15 hello hello Here are some more example programs; they're not likely to compile or run, they're just for looking at to learn the language: http://history.dcs.ed.ac.uk/archive/languages/hal/7502/hal7502.i15 http://history.dcs.ed.ac.uk/archive/languages/hal/interdata/hal70.i15 http://history.dcs.ed.ac.uk/archive/os/pdp915/edit15.txt http://history.dcs.ed.ac.uk/archive/os/pdp915/decode.txt The original pdp15 operating system (not needed for this compiler) is here: http://history.dcs.ed.ac.uk/archive/os/pdp915/ The operating system was basically a run-time environment for the Imp compiler. Graham