ballz
d538cf46e2
Replace busy-wait frame counter with a 50 Hz raster IRQ at line 311 (PAL stable line). The IRQ handler increments a 16-bit frame_count and calls game_step() once per frame. Per-state timing now uses enter_frame timestamps + frame_count comparisons. - New tick.h/tick.c: install one RIRQ via Oscar64's rirq library, call a __interrupt handler that bumps frame_count and runs the state machine. Mask CIA 1 + CIA 2 IRQs and set RST8 (the high bit of the 9-bit raster register) so the IRQ fires at line 311 not line 55. - game.h: expose volatile frame_count, replace per-state 'frame' counter with enter_frame timestamps. - game.c: use frame_count - enter_frame everywhere; sample SID $D41B at READY enter for a random 100..250 frame WAIT duration; trigger a low-square-wave stinger on SID voice 1 when DRAW faults out (no fire for 500 frames) and gate it off ~0.2 sec later via a counter decremented every frame. - main.c: replace the busy-wait loop with rasterirq_setup() and an empty for(;;); idle. (Filename is tick.c/.h not rasterirq.c/.h because the oscar64 library's own rasterirq.c does '#include "rasterirq.h"' to pull in its own header, and that include would otherwise pick up ours and lose NUM_IRQS.)
nyuller
A C64 programming project using Oscar64
as the cross-compiler. Oscar64 is checked in as a git submodule under
./oscar64/.
Layout
.
├── oscar64/ # Oscar64 cross-compiler (git submodule)
├── docs/c64/ # Low-level C64 reference (memory map, VIC, CIA, SID, …)
├── src/ # Your C code
│ ├── helloworld.c
│ └── build.sh # Compile + run helper
├── OSCAR64.md # Notes on the Oscar64 compiler internals
└── PROG_C64.md # Notes on programming the C64 hardware
First-time setup
# 1. Clone with submodules:
git clone --recurse-submodules <this-repo-url>
# Or, if you already cloned without --recurse-submodules:
git submodule update --init --recursive
Building
cd src
./build.sh # compile helloworld.c → src/build/helloworld.prg
./build.sh -e # run in oscar64's built-in emulator (headless, fast)
./build.sh -v # run in VICE x64 (interactive, needs a real display)
./build.sh -V # run in VICE x64sc (interactive, cycle-exact)
./build.sh -c # just compile
build.sh will build the oscar64 compiler automatically the first time
(it runs make -C make compiler inside ./oscar64/ if
./oscar64/bin/oscar64 doesn't exist yet).
Default test tool is the oscar64 built-in emulator (-e): it
runs headless, needs no ROMs, no display, and is fast. Every Verify
step in tasks.md uses this.
VICE 3.9 is installed at /usr/bin/ (x64, x64sc, x128,
xvic, xpet) and is available via -v / -V. It is a GUI
emulator and needs a real X11 / Wayland display to render — it
won't produce useful screenshots in this headless environment.
Use it from a real terminal session for interactive play-testing
and cycle-exact validation of raster IRQ and SID timing; don't
expect to script it.
Documentation
PROG_C64.md— how the C64 hardware actually works, from a low-level programming perspective. Start here if you want to understand what's going on under the hood.OSCAR64.md— how the Oscar64 compiler works internally, plus a C64- specific section on how to use it well (memory model, bank switching, raster IRQs, common mistakes).docs/c64/— downloaded reference material: the full Commodore 64 Programmer's Reference Guide text, Christian Bauer's canonical VIC-II paper, and per-chip reference notes.