Changes
/* BRK / IRQ / NMI / RESET */
On a BRK instruction, the CPU does the same as in the IRQ case, but sets bit #4 (B flag) in the copy of the status register that is saved on the stack.
The priority sequence for interrupts, from top priority to bottom, is as follows: RESET, NMI, BRK, IRQ.
=== Half Cycles ===
