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Half-Carry Flag: Difference between revisions
From SnesLab
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Whenever H is set, the [[overflow flag]] is set as well. | Whenever H is set, the [[overflow flag]] is set as well. | ||
Both [[DAA]] and [[DAS]] examine the half-carry flag. | |||
[[Category:ASM]] | [[Category:ASM]] | ||
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=== See Also === | === See Also === | ||
* [[Decimal Mode]] | * [[Decimal Mode]] | ||
* [[Carry Flag]] | * [[Carry Flag]] | ||
Revision as of 22:32, 4 August 2024
The Half-carry flag (H) exists on the SPC700, as bit 3 of the Program Status Word. It applies to the bottom 4 bits of the accumulator, meaning it is set whenever bit 3 of an ALU operation carries over into bit 4.
It is cleared by CLRV, but there is no SETV command to set it.
Whenever H is set, the overflow flag is set as well.
Both DAA and DAS examine the half-carry flag.
See Also
References
- https://problemkaputt.de/fullsnes.htm#snesapuspc700cpuoverview
- Page 3-8-6 of Book I of the official Super Nintendo development manual