Talk:RAMBO-1: Difference between revisions

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== IRQ related - Hard Drivin' ==
== IRQ related - Hard Drivin' ==
Suggested changes for the Mapper64 IRQ. It makes Hard Drivin' to work fine. No games are affected with this change.


Next CPU clock:
Next CPU clock:

Revision as of 00:29, 13 January 2014

As for the 2mb PRG, I'm not sure if the cart actually supports that much ROM, but the PRG registers apparently are 8 bits, and 8kb * $100 = 2048kb = 2mb. --Drag 03:05, 9 November 2011 (UTC)

IRQ related - Hard Drivin'

Suggested changes for the Mapper64 IRQ. It makes Hard Drivin' to work fine. No games are affected with this change.

Next CPU clock:

  • IF $C001 was written to after previous clock
    • reload IRQ counter with IRQ Reload value PLUS ONE
  • ELSE IF IRQ counter is 0
    • reload IRQ counter with IRQ Reload value

When the IRQ is clocked:

    • Decrement IRQ counter by 1
    • IF IRQ counter is now 0 AND IRQs are enabled
      • wait one M2 cycle, then trigger IRQ

Hard Drivin' works. --Zepper (talk) 21:14, 11 January 2014 (MST)