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B Flag (Super FX): Difference between revisions

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(many instructions clear it)
m (Xetheria moved page B Flag to B Flag (Super FX): there is a b flag on the 6502 too)
 
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The '''B flag''' is on the [[Super FX]], and is set when [[WITH]] runs.
The '''B Flag''' is on the [[Super FX]], and is set when [[WITH]] runs.  It is bit 4 of SFR.


Many instructions clear the B flag.
These instructions change their behaviour on the B flag:
 
*  [[TO]] R<sub>n'</sub> as [[MOVE]] R<sub>n</sub>,R<sub>n'</sub>
*  [[FROM]] R<sub>n'</sub> as [[MOVES]] R<sub>n</sub>,R<sub>n'</sub>
 
For both of them, the R<sub>n</sub> is set by the preceeeding WITH R<sub>n</sub>.
 
Many instructions clear the B flag, including:
 
* [[GSU/ADC|ADC]] R<sub>n</sub>
* [[GSU/ADC|ADC]] #n
* [[ADD]] R<sub>n</sub>
* [[ADD]] #n
* [[GSU/AND|AND]] R<sub>n</sub>
* [[GSU/AND|AND]] #n
* [[ASR]]
* [[BIC]] R<sub>n</sub>
* [[BIC]] #n
* [[CACHE]]
* [[CMODE]]
* [[GSU/CMP|CMP]] R<sub>n</sub>
* [[COLOR]]
* [[GSU/DEC|DEC]] R<sub>n</sub>
* [[DIV2]]
* [[FMULT]]
* [[GETB]]
* [[GETBH]]
* [[GETBL]]
* [[GETBS]]
* [[GETC]]
* [[HIB]]
* [[IBT]] R<sub>n</sub>, #pp
* [[GSU/INC|INC]] R<sub>n</sub>
* [[IWT]] R<sub>n</sub>, #xx
* [[GSU/JMP|JMP]] R<sub>n</sub>
* [[LDB]] (R<sub>m</sub>)
* [[LDW]] (R<sub>m</sub>)
* [[LEA]] R<sub>n</sub>, xx
* [[LINK]] #n
* [[LJMP]] R<sub>n</sub>
* [[LM]] R<sub>n</sub>, (xx)
* [[LMS]] R<sub>n</sub>, (yy)
* [[LMULT]]
* [[LOB]]
* [[LOOP]]
* [[GSU/LSR|LSR]]
* [[MERGE]]
* [[MOVE]] R<sub>n</sub>, R<sub>n</sub>'
* [[MOVES]] R<sub>n</sub>, R<sub>n</sub>'
* [[MULT]] R<sub>n</sub>
* [[MULT]] #n
* [[GSU/NOP|NOP]]
* [[NOT]]
* [[OR]] R<sub>n</sub>
* [[OR]] #n
* [[PLOT]]
* [[RAMB]]
* [[GSU/ROL|ROL]]
* [[ROMB]]
* [[GSU/ROR|ROR]]
* [[RPIX]]
* [[GSU/SBC|SBC]] R<sub>n</sub>
* [[SBK]]
* [[SEX]]
* [[SM]] (xx), R<sub>n</sub>
* [[SMS]] (yy), R<sub>n</sub>
* [[STB]] (R<sub>m</sub>)
* [[STOP]]
* [[STW]] (R<sub>m</sub>)
* [[SUB]] R<sub>n</sub>
* [[SUB]] #n
* [[SWAP]]
* [[UMULT]] R<sub>n</sub>
* and presumably UMULT #n too


=== See Also ===
=== See Also ===
* [[Dither Flag]]
* [[Dither Flag]]
* [[Break Flag]]
* [[Break Flag]]
* [[ALT1]]
* [[ALT2]]
* [[ALT0]]


=== Reference ===
=== References ===
* [https://archive.org/details/SNESDevManual/book2/page/n158 page 2-9-2 of Book II] of the official Super Nintendo development manual
* [https://archive.org/details/SNESDevManual/book2/page/n158 page 2-9-2 of Book II] of the official Super Nintendo development manual
* [https://archive.org/details/SNESDevManual/book2/page/n110 page 2-4-4 of Book II], lbid.


[[Category:Flags]]
[[Category:Flags]]
[[Category:Super FX]]
[[Category:Super FX]]
[[Category:ASM]]
[[Category:ASM]]

Latest revision as of 23:06, 21 July 2024

The B Flag is on the Super FX, and is set when WITH runs. It is bit 4 of SFR.

These instructions change their behaviour on the B flag:

For both of them, the Rn is set by the preceeeding WITH Rn.

Many instructions clear the B flag, including:

See Also

References