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MEGA65 / mega65-core

MEGA65 FPGA core
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C65 demo does not run on core 3253c5d, but does run on XEMU and slot 0 core #601

Closed MauriceMEGA65 closed 1 year ago

MauriceMEGA65 commented 2 years ago

Test Environment (required) You can use MEGA65INFO to retrieve this.

Describe the bug C65 demo (see attached) does not run on latest core, but runs OK on core in slot 0 and on XEMU

To Reproduce Steps to reproduce the behavior:

  1. Boot with old ROM (911001)

  2. Mount ZED-YAGO.D81 (see attached) zed_yago.d81.zip

  3. Load and run DEMOLOAD65 (will switch to C64 mode)

  4. In C64 mode, load and run DEMOLOAD64

Expected behavior Same as on XEMU or real hardware booted with slot 0 core

Screenshots If applicable, add screenshots to help explain your problem.

Additional context Audio seems OK, video is effected/scrambled

lgblgblgb commented 2 years ago

I'm not sure how important that is, since: https://github.com/lgblgblgb/xemu/issues/142#issuecomment-855451262

So it can happen it's just a coincidence that it runs with older bitstream (slot 0) or Xemu. But I can't judge this clearly anyway. At the other hand if it runs with "slot 0" core, it may mean a bug rather than being simply "moved away from being compatible". Hmm.

lydon42 commented 1 year ago

A slot 0 core is just a very old core. As we are adding enhancements, old stuff intended for the "real" C65 will probably break, it is not possible to enhance and keep old the old "quirks". So if you like to run a very old example, make sure to use an equally old core.