CAESAR Logo

Catalogue of Arcade Emulation Software - the Absolute Reference

Valid XHTML 1.0! Valid CSS!

X-Arcade

X-Arcade

Large CAESAR Logo

thunderj.c

0.36b2 [Aaron Giles]


NOTES:

- Video Controller Hack: Sigh. CPU #1 reads the video controller register twice per frame, once at the beginning of interrupt and once near the end. It stores these values in a table starting at $163484. CPU #2 periodically looks at this table to make sure that it is getting interrupts at the appropriate times, and that the VBLANK bit is set appropriately. Unfortunately, due to all the cpu_yield() calls we make to synchronize the two CPUs, we occasionally get out of time and generate the interrupt outside of the tight tolerances CPU #2 expects. So we fake it. Returning scanlines $f5 and $f7 alternately provides the correct answer that causes CPU #2 to be happy and not aggressively trash memory (which is what it does if this interrupt test fails -- see the code at $1E56 to see!).


WIP:

- 0.36b2: Added thunderj.c driver.