OLApps_SPuD

Created: 2012-08-21 11:53
Updated: 2015-06-22 04:59

README.md

Simply Programmable microProcessor Device

What is this?

It's a microprocessor emulator, for simple microprocessors. The cool bit is that you can invent your own with a DSL, let's call it SPuDLang. Once you've described your processor in SPuDLang, this thing will run it.

What's inside?

  • /standalone/ui: a browser user interface (which can run in any browser environment). This also seems to have a jQuery plugin for the browser to render a fancy circuit board which lights up and makes sounds and things like that.
  • /standalone/emulator: a flexible emulator backend with its own definition language for building any processor (InterpretedProcessor). This can be run in the browser, or as a coffeescript/nodejs library on the commandline.
  • /standalone/emulator/connection: some different ways of passing messages from the browser UI to the emulator code. Emu.coffee is a good place to look to see that interface.
  • Also, some glue to tie the browser stuff to an old OpenLearning system (the other top-level dirs that are not /standalone, i.e. /src, /media, etc.).

How do SPuDLang?

Take a look in /standalone/docs, it has a grammar for the language. If you want to try it out in coffeescript on the commandline, there's an example for that at /standalone/example4004.coffee

A SPuD definition has 3 sections:

  • it's name, register, and memory setup
  • descriptions of the instructions
  • how to execute the instructions

Instruction implementations in the 3rd section are of the form:

<instruction number>, <number of bytes> <implementation>.

Here's a definition:

name: 4004
memoryBitSize: 4
numMemoryAddresses: 16
registerBitSize: 4
registerNames: IP, IS, R0, R1, SW
[descriptions]
0: Halt
1: Increment R0 (R0 = R0 + 1)
2: Decrement R0 (R0 = R0 - 1)
3: Increment R1 (R1 = R1 + 1)
4: Decrement R1 (R1 = R1 - 1)
5: Add (R0 = R0 + R1)                           
6: Subtract (R0 = R0 - R1)
7: Print R0; Ring Bell
8: Jump to address <data> if R0 != 0
9: Jump to address <data> if R0 == 0
10: Load <data> in to R0
11: Load <data> in to R1
12: Store R0 into address <data>
13: Store R1 into address <data>
14: Swap R0 and address <data>
15: Swap R1 and address <data>
[instructions]
0, 1: halt.
1, 1: R0++.
2, 1: R0--.
3, 1: R1++.
4, 1: R1--.
5, 1: R0 = R0 + R1.
6, 1: R0 = R0 - R1.
7, 1: print(R0); bell.
8, 2 case R0 != 0: IP = [IP-1].
9, 2 case R0 == 0: IP = [IP-1].
10, 2: R0 = [IP-1].
11, 2: R1 = [IP-1].
12, 2: [[IP-1]] = R0.
13, 2: [[IP-1]] = R1.
14, 2: SW = [[IP-1]]; [[IP-1]] = R0; R0 = SW.
15, 2: SW = [[IP-1]]; [[IP-1]] = R1; R1 = SW.
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