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Ensures NMI can no longer usurp BRK on 65C02s.

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This commit is contained in:
Thomas Harte 2018-08-14 19:33:48 -04:00
parent be01203cc1
commit 1eca4463b3
1 changed files with 7 additions and 3 deletions
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10
Processors/6502/Implementation/6502Implementation.hpp
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@ -140,9 +140,13 @@ if(number_of_cycles <= Cycles(0)) break;
case CycleReadFromPC: throwaway_read(pc_.full); break;
case OperationBRKPickVector:
// NMI can usurp BRK-vector operations
nextAddress.full = (interrupt_requests_ & InterruptRequestFlags::NMI) ? 0xfffa : 0xfffe;
interrupt_requests_ &= ~InterruptRequestFlags::NMI; // TODO: this probably doesn't happen now?
if(is_65c02(personality)) {
nextAddress.full = 0xfffe;
} else {
// NMI can usurp BRK-vector operations on the pre-C 6502s.
nextAddress.full = (interrupt_requests_ & InterruptRequestFlags::NMI) ? 0xfffa : 0xfffe;
interrupt_requests_ &= ~InterruptRequestFlags::NMI;
}
continue;
case OperationNMIPickVector: nextAddress.full = 0xfffa; continue;
case OperationRSTPickVector: nextAddress.full = 0xfffc; continue;