TomHarte/CLK 2019-12-25

on GitHub

This release:

• adds an Atari ST emulation that still needs a lot of work:
  • only ST and MSA files are supported so far, not the much superior STX — and they're always read-only;
  • only a high-level emulation is offered of the keyboard, mouse and joystick side of that serial interface, and even that's incomplete;
  • the video emulation is immature — many border-breaking full-screen effects work, but not all; and
  • even within those constraints, a decent amount of software just doesn't seem to work correctly.

Improvements will be forthcoming.

However, in pursuit of the Atari ST the following have been fixed to the benefit of other machines:

• 68000 corrections, also benefitting the Macintosh, powered by randomised comparative testing:
  • CMPA.w no longer truncates the destination register for computation;
  • NBCD (An)+ and -(An), no longer always adjust An by two;
  • CHK no longer changes the N flag when the result is within bounds;
  • MOVE -(An), SR/CCR both now actually predecrement; and
  • SBCD sets carry and extend exactly when it adjusts the top nibble;
• WD corrections, also benefitting the Oric, Electron and MSX:
  • multi-sector reads and writes no longer sometimes use a sector body as if it were an address (with the side effect that spurious CRC errors don't occur);
  • fixes have been applied to the track-zero and write-protect flags; and
  • the index pulse is now detectable in software.