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Break Flag: Difference between revisions
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Note: This page may be confusing or inaccurate. See the talk page. | Note: This page may be confusing or inaccurate. See the talk page. | ||
The '''Break Flag''' (B) | The '''Break Flag''' (B) is bit 4 of the [[S-SMP]]'s [[program status word]]. It discerns between [[IRQ]]s and [[BRK]]. | ||
BRK and [[PHP]]<sup>[dubious]</sup> set the break flag. IRQs, [[NMI]]s, and reset clear it.<sup>[1]</sup> | BRK and [[PHP]]<sup>[dubious]</sup> set the break flag. IRQs, [[NMI]]s, and reset clear it.<sup>[1]</sup> | ||
Revision as of 18:05, 12 August 2024
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
- https://problemkaputt.de/fullsnes.htm#cpuregistersandflags
- Eyes & Lichty, page 422, Table 18.2. 65x Flags.
- page 486, lbid.