3 ms·

I wonder if this is a stock 6052 running this OS? Anyone know?

• dsp1234 11y ago
  In addition to this, Jörn convinced me that pre-emptive multitasking was possible on the 6502, so in May 2014, I began the arduous task of converting the existing code to run from a bank-switched cartridge, while simultaneously designing the pre-emptively multitasking kernel. What is especially heartening at this stage is that the 8-bit Atari can actually run a pre-emptive scheduler, and run it well – in spite of the 6502’s fixed stack. Looks like it is.
  • alain94040 11y ago
    In 1987 I published a preemptive multitasking for 6502[1] (Apple II). If I remember properly (it's only been 30 years or so), the stack is fixed at $100, so all you need to do on a context switch is save the stack somewhere else and restore it. That's 256 bytes to move around. I used the mouse card as an interrupt source (video refresh) to get a regular source of interrupts. [1] I can't find any trace online, except for some weird Word document of what must have been the original README file.
• chipsy 11y ago
  The main thing that is unlike the original hardware is the 128kb memory target and the addition of a mouse. The 64kb era was effectively ushered in with the C64 and 800XL in 1982, but 128kb came a few years later and concurrent with a market shift to 16-bit CPUs. Accessing that much memory on an 8-bit isn't a natural fit for their addressing capability, even though there are several examples of models shipping with it. (In a lot of ways memory posed a bigger problem than CPU time back then.)
• ddingus 11y ago
  I've been following this developer for some time. Yes, stock CPU, 1.7Mhz.