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CLV: Difference between revisions
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!colspan="8"|Basic Info | !colspan="8"|Basic Info | ||
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|'''Speed''' | |'''Speed''' | ||
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| | |[[Implied]] (type 2) | ||
|B8 | |B8 | ||
|1 byte | |1 byte | ||
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!colspan="9"|Flags | !colspan="9"|Flags Affected | ||
|+ | |+ | ||
|N | |[[Negative Flag|N]] | ||
|V | |[[Overflow Flag|V]] | ||
|M | |[[M Flag|M]] | ||
|X | |[[X Flag|X]] | ||
|D | |[[Decimal Flag|D]] | ||
|I | |[[I Flag|I]] | ||
|Z | |[[Zero Flag|Z]] | ||
|C | |[[Carry Flag|C]] | ||
|+ | |+ | ||
|. | |. | ||
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|} | |} | ||
'''CLV''' is a 65x instruction that clears the [[overflow flag]]. | |||
No other flags are affected. | |||
==== Syntax ==== | |||
<pre> | |||
CLV | |||
</pre> | |||
==== Example ==== | |||
Before [[BRA]] was invented on the 65c02, this was a common way to always branch on the original 6502: | |||
<pre> | |||
CLV | |||
BVC nearlabel | |||
</pre> | |||
To clear another flag at the same time as V, use [[REP]]. | |||
=== See Also === | |||
* [[CLC]] | |||
* [[CLRV]] | |||
* [[BIT]] | |||
* [[BVC]] | |||
* [[SEV]] | |||
=== External Links === | |||
* [[Eyes & Lichty]], [https://archive.org/details/0893037893ProgrammingThe65816/page/444 page 444] on CLV | |||
* [[Labiak]], [https://archive.org/details/Programming_the_65816/page/n143 page 133] on CLV | |||
* 3.6.1 on [[MCS6500 Manual]], [https://archive.org/details/mos_microcomputers_programming_manual/page/n43 page 28] on CLV | |||
* [[Carr]], [https://archive.org/details/6502UsersManual/page/n267 page 254] on CLV | |||
* [[Leventhal]], [https://archive.org/details/6502-assembly-language-programming/page/n104 page 3-55] on CLV | |||
* snes9x implementation of CLV: https://github.com/snes9xgit/snes9x/blob/master/cpuops.cpp#L1434 | |||
[[Category:ASM]] | [[Category:ASM]] | ||
[[Category:Inherited from 6502]] | [[Category:Inherited from 6502]] | ||
[[Category:One-byte Instructions]] | |||
[[Category:Implied Instructions]] | |||
[[Category:Two-cycle Instructions]] | |||
Latest revision as of 01:49, 10 August 2024
| Basic Info | |||||||
|---|---|---|---|---|---|---|---|
| Addressing Mode | Opcode | Length | Speed | ||||
| Implied (type 2) | B8 | 1 byte | 2 cycles | ||||
| Flags Affected | ||||||||
|---|---|---|---|---|---|---|---|---|
| N | V | M | X | D | I | Z | C | |
| . | 0 | . | . | . | . | . | . | |
CLV is a 65x instruction that clears the overflow flag.
No other flags are affected.
Syntax
CLV
Example
Before BRA was invented on the 65c02, this was a common way to always branch on the original 6502:
CLV BVC nearlabel
To clear another flag at the same time as V, use REP.
See Also
External Links
- Eyes & Lichty, page 444 on CLV
- Labiak, page 133 on CLV
- 3.6.1 on MCS6500 Manual, page 28 on CLV
- Carr, page 254 on CLV
- Leventhal, page 3-55 on CLV
- snes9x implementation of CLV: https://github.com/snes9xgit/snes9x/blob/master/cpuops.cpp#L1434