Gigatron Simulator / Assembler

This simulator is a quick-hack; a merge between https://github.com/PhilThomas/gigatron and https://github.com/hlorenzi/customasm to allow real-time assembling / debugging of the Gigatron simulator

The simulator loads the ROM using an XmlHttpRequest, so the application must be served up over HTTP.

The package.json can install an HTTP server, just do:

npm install

Download ROMv2.rom into the src directory.

Start the HTTP server

npm start

Point your browser at localhost:8000/src.

Click on the canvas (Gigatron screen) to give it keyboard focus Use the cursor keys for the D-pad.

GT1 Files

GT1 files can be loaded by starting the Loader and dropping a .gt1 file onto the VGA display from File Explorer or Finder.

Assembler

• Uncheck Run to pause the emulator.
• use one of the load .. buttons to load a sample program (including the CPU definition of the Gigatron)
• Use assemble to assemble and upload the instructions
• reset resets the program pointer
• Use step for one clockcycle
• auto will try to assemble and upload automatically after each keypress
• NOP padding pads the rest of the program ROM with 'no-operation' instructions

Notes

• The first section of the assembly (#cpudef) is used to translate mnemonics to HEX codes (which are used to create the actual ROM binary)
• Currently, only the first 16 bytes of RAM are displayed

TODO:

• export asm button: export the current assembly instructions onto the local harddisk
• export hex button: export the hex (intermediate code) onto the local harddisk
• export rom button: export the binary rom for usage on a real EPROM
• Look into a way for a hardware acurate input (and allow support for keyboard)