GSSquared Emulator version 0.7.0 Released

February 3, 2026

From Jawaid bazyar:
I’m pleased to announce the release of GSSquared 0.7.0.

GSSquared is an Apple II series computer emulator.

Supported platforms are:

Apple ][
Apple ][ Plus
Apple //e
Apple //e Enhanced
Apple //e Enhanced with 65816 CPU and Super Hires Video
Apple IIgs ROM 01

Pre-built binaries available for:

MacOS (Intel and Apple Silicon)
Windows 10+
Linux AppImage (Should run on many linux, but I tested on Ubuntu 22).

New for this release is the Apple IIgs support. Here’s what the IIgs includes, and does not include:

Includes: ‘816 CPU, accelerated speeds up to 14MHz, ADB Mouse + Keyboard, partially-working Ensoniq Sound, Disk II and Block Device models; text, background, border colors; SHR; VBL, 1/4 sec, 1 sec, scb interrupts; two-button mouse support (use with SideClick); realtime clock (shows local system time); mouse speed adjustment (normal/fast) works; slot rom mapping; battery ram;

Does not include: IWM (no true “GS-style” disk yet); Serial chip; ROM03 support; SHR fill mode.

An effort has been made to make the GS cycle-accurate. The work so far does provide an average 2.58MHz operating speed, and it passes the built-in selftest Test 5 (“speed test”). However, Textfunk does not run correctly yet, so there is clearly work to do.

Working examples: Arkanoid, Arkanoid II, my hard drive, System 6.0 generally; 3200-color picture viewers (at normal speed);
Not-quite working examples: QIX (sound plays more slowly than it should, though the game does play).
Totally non-working: Christmas demo, Nucleus demo

I’m hoping to get some feedback on edge cases that don’t work, so get at it!

Other key developments:

pulled all system clock code into a single C++ module, and lots of clocking cleanup
idle time display in lower left corner of screen;
Apple II speaker now automatically re-syncs correctly when a naughty OS makes us skip frames.
some fixes to Mockingboard, works in Ultima V now
continued removing unnecessary cross-dependencies from the CPU code

Debugger: