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Break Flag

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Note: This page may be confusing or inaccurate. See the talk page.

The Break Flag (B) is bit 4 of the S-SMP's program status word. It discerns between IRQs and BRK.

BRK and PHP[dubious] set the break flag. IRQs, NMIs, and reset clear it.[1]

RETI and POP can modify the break flag.

In emulation mode the 65c816 has a break flag too.[2] But in native mode it becomes the Index Register Select. PLP can affect the break flag.[3]

See Also

References

  1. https://problemkaputt.de/fullsnes.htm#cpuregistersandflags
  2. Eyes & Lichty, page 422, Table 18.2. 65x Flags.
  3. page 486, lbid.
  4. Fragment 18.1 on page 436 on BRK, lbid.