Hello World for the NES

This is a simple skeleton project for the Nintendo Entertainment System.

Architecture

The NMI handler is responsible for updating PPU memory (during the vertical blanking interval) by executing commands placed into a command buffer by the main thread of execution. The NMI handler will not execute any commands unless the main thread is blocking in run_nmi.

All other tasks should be performed in the main thread: game logic, input processing, etc.

To queue a command for the NMI handler: ldy cmd_off, store bytes into the queue using .ccmd and/or .cmd, then sty cmd_off. Then, to wait for the next frame and execute pending commands, jsr run_nmi.

Build requirements

64tass
C compiler
Make

Building

make

Notes

The code addresses in the first column of the .lst file are $7ff0 bytes too low.
64tass emits warning: memory bank exceeded at build time. This warning is harmless and there doesn't seem to be a way to avoid it.

Useful links