assembler.py is a fairly basic assembler to aid in programming the 8-bit computer. It supports labels, macros, file includes, sections (text, rodata, data, bss), and not much else.

Programs of interest

• zmach/: a Z-Machine for running text adventure games
• vga/vga_tetris.asm: a Tetris-style game (in color!)
• kernel/: a prototype kernel capable of loading ram-only programs

Usage

Programs can be assembled in either raw_ram_only or raw_flash_ram styles. raw_flash_ram programs can be written to and run directly from the computer's flash memory chips. raw_ram_only programs must be copied to ram before they're run (this is done via the prototype kernel). Set this option via the conf_out_style variable at the top of assembler.py.

For hardware version 2, assemble and upload the program per upload-new.sh and the 8-bit_prgm_flash_v5 Arduino sketch. The program will be stored on a flash chip attached to an Arduino Mega, and the Arduino will take care of programming the computer's flash chips in-system.

[TODO: hardware version 3]

Emulator

An emulator that simulates the main computer, VGA expansion board, and keyboard buffer is in sim_vga.c (requires ncurses).

Assembly language format

[TODO]

Quirks

• raw_flash_ram programs cannot have initialized read-write data, on account of needing a kernel to help them load it. The prototype kernel does not support such loading.
• If the raw_flash_ram output style is used (with a bss section), performance is quite bad. This is due to handling section layout by padding the input assembler code with no-ops, which then must all be processed. A simple optimization to skip processing these padding instructions would resolve the problem.
• OUTPUT_MODE should always be "raw"; other output modes were once used for other program-uploading mechanisms.