Fixes:

• CGIA NMI stuck low. The renderer and the PIX interrupt could lose an acknowledge, and the edge triggered NMI never fired again. Programs froze waiting for VBI while the picture kept going. State changes are serialized now.
• VRAM cache tags were lying across bank switches.
• MODE1 2/3/4 bpp encoder read the scan address instead of the bitmap.
• USB: a DualShock 4 froze programs within seconds. The host driver and TinyUSB come from upstream RP6502 now, and the slots running out is handled.
• Unbacked HID pad slots read as disconnected.

Rob Hubbard SIDs got the most love. The importer no longer walks the player by its driver name - it finds each routine by its opcode signature and reads the data from the operands. Init is walked statically, so the tempo cell and the track pointers are read as init left them. I swept every Hubbard .sid on HVSC against its own 6502: 150 of 213 builds are within 2% of the original tempo, up from 118. For 19 files the walk can’t be followed, so they refuse to import rather than play wrong.

VGM rips had notes drifting. The YM2151 tunes in the playlist played 13.6% of their notes more than 50 cents out. Now 0.0%. Chip volumes from the VGM extra header are applied as balance, PSG envelopes are no longer applied twice, and SegaPCM channels parked at zero volume are ignored.

Smaller stuff: volume fades on A2M, RAD and .kt slide on the row’s first tick, instruments without a sample stay silent in MOD/XM/S3M/IT, and the VU meters follow the live VOL register.

I’ve added a hazard to the arena: a gang of ghosts. They don’t show up for free

• they come when it is earned, they hunt you four different ways, and what they touch dies. Blinky picks up pace as the arena wears down, and there is a siren to let you know.

Faces are patched into the sprite frames as they turn, and each ghost keeps the face the pack drew.

The interesting part is under the hood. Sprites reach the chip only in the blanking now, via two descriptor pages. The vertical blank interrupt only moves a pointer, so a face can never tear. Then a week of profiling to see what every tick pays for: painting the status panel a few fields at a time, spreading blasts over ticks and paying a late tick back with a catch-up that draws nothing.

A playlist is a text file with one tune per line - a full URL or a path into one of the archives, optionally with &song=N for a sub-song. The tracker imports each tune on the fly and plays it on SGU-1, one after another, forever. It reshuffles every lap, and a song is capped to 10 minutes of playing time unless you say otherwise with --seconds.

There is a Playlist band in the File menu with prev/next and info, in both the GUI and the TUI. The browser version keeps ticking in hidden tabs too, so you can put it in the background and work.

I’ve made one for us, with about 245 tunes: C64 SID, Atari POKEY, AdLib, Yamaha FM, Amiga modules, MIDI. The first hundred came from rankings, then some Polish composers were added, then I listened to all of it and removed the crappy ones. The sources are in the jukebox directory of the mono repo.

Shuffle and play: https://tracker.x65.zone/?playlist=https://raw.githubusercontent.com/X65/X65/refs/heads/main/jukebox/play.lst&shuffle&play

Any playlist reachable over HTTPS works the same way.

BOOM!65 is a game for X65, written in 65816 assembly. It started as a port of the Atari 8-bit Dynakillers Unchained by Matosimi. The port is done and the game has since wandered off on its own.

It is a good torture test for the machine, so it uses everything:

• The arena is CGIA MODE2 attributed text, a 33×19 map of 12×12 pixel tiles, scrolled six pixels. A flame is only an ink change on ordinary glyphs.
• Players are 4 bpp sprites. Pick your character with the d-pad on the bench.
• Up to fifteen USB gamepads, plus two DE-9 sticks as a fallback.
• Bombs, chain reactions, curses and boons, and an arena that repairs itself.
• Sound effects replayed on SGU-1 PCM voices, with the original’s tune playing while the machine is idle.
• Troublemakers - bomb dropping bots that fill empty slots.

It also gave Emu a good kick. Most of the pad scripting and the screenshot fixes came from testing this game headlessly.

Play it in the browser. Plug in a gamepad and press a button, so the browser notices it.

POKEY can high-pass filter one channel with another, and many Atari tunes use it for that crispy sound. SGU Tracker now models those voices, together with the proper distortion mapping, track routing and pulse widths, across CMC, MPT, RMT and TMC imports.

A few drums were wrong too. The duty cycle wasn’t applied to every voice, and the MPT accent 2 didn’t take its pitch from the note. Fixed.

RMT volume slides keep their decay in the volume column now, instead of dropping it on the floor.

New in the test corpus: Lasermania by Janusz Pelc. If your ears bleed, it is working.

Each sprite now picks its depth, from 1 to 4 bpp, in its flags byte, and every sprite gets a 16 entry palette. Pixel data uses the same packing as MODE1, so you only need one idea in your head for both.

The palette is assembled per scanline:

• entries 0–3 come from the sprite descriptor colors
• entries 4–11 are new color registers of the sprite plane
• entries 12–15 are the descriptor colors again, half-bright

Entry 0 stays transparent. So 1 bpp reaches entry 1, 2 bpp reaches 1–3, 3 bpp 1–7 and 4 bpp everything.

GOTCHA: This breaks existing programs. 1 bpp sprites now draw color[1] and 2 bpp sprites need their flags byte and data layout regenerated. SPRITE_MASK_MULTICOLOR stays as an alias for 2 bpp, so old sources recompile, but the pixel data needs repacking.

The firmware has it, Emu follows it, and the examples got the new header and shared palettes. Remember to update your cgia.h.

Until now the joy verb reached joystick 1 and nothing else. Anything with more than two players lives on the USB HID gamepads, and those were fed only by real SDL devices, so a four-player game was impossible to test headlessly. Not anymore:

pad 3 right a
run 30
pad 3 off
key "x"

• pad <1..15> injects a gamepad report into a slot, analog sticks included. pad <n> off lets go and hands the slot back to a real device, if any.
• joy can drive either DE-9 port and names the buttons A, B, X and Y.
• key types on the keyboard.

Fifteen is not a random number. It is all that fits into the selector nibble of the HID register window. The status line now shows the merged pad state, so you can see what the machine sees.

In the browser, gamepads are now read raw, the way the firmware reads them. Beware the browser’s privacy gate: a page doesn’t see a pad until you press a button on it.

Also in this batch: a custom X65 mouse cursor, the screensaver is inhibited while in fullscreen, and AudioWorklet failures are reported as suspended audio instead of silence.

And shot and crc now capture the frame as displayed, not the raw raster.

Adam Gilmore wrote it for the Atari 8-bit. You can now listen to it on X65.

I’ve spent the last couple of days implementing Atari music imports in SGU Tracker. POKEY’s four channels can use different clocks, be paired together and apply high-pass filtering. This is not straightforward to translate for FM synthesis.

The importer reads music from:

• Raster Music Tracker
• Chaos Music Composer
• Music ProTracker, including digi samples
• Theta Music Composer 1.x and 2.x
• Adam Gilmore’s player

Each player needs its own data decoder. Some even set the playback rate in the player code, so the song data alone is not enough to get the tempo right.

Additionally, the Atari SAP Music Archive is available as asma:/ in the file dialog. It lists the SAP files that pass an import check, along with the archive’s standalone RMT modules.

Try it in your browser: https://tracker.x65.zone/

• Alloyrun by VOID, from Reality AdLib Tracker (.rad)
• FM-Tronikk by Malfunction/Altair, from AdLib Tracker II (.a2m)
• Pinball Illusions by Olof Gustafsson, from an Amiga ProTracker module (.mod)
• E1M1: At Doom’s Gate by Bobby Prince, from a General MIDI file (.mid)

Each tune was imported into SGU Tracker and exported as an SGM module bundled with the 6502 player in an autorun XEX file. Emu runs that player as an X65 program, driving the emulated SGU-1.

These demos show the import and export path working with AdLib FM instruments, Amiga samples and General MIDI music.