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CLV: Difference between revisions
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'''CLV''' is a 65x instruction that clears the [[overflow flag]]. | '''CLV''' is a 65x instruction that clears the [[overflow flag]]. | ||
No other flags are affected. | |||
==== Syntax ==== | ==== Syntax ==== | ||
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==== Example ==== | ==== Example ==== | ||
Before [[BRA]], this was a common way to always branch on the 6502: | Before [[BRA]] was invented on the 65c02, this was a common way to always branch on the original 6502: | ||
<pre> | <pre> | ||
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BVC nearlabel | BVC nearlabel | ||
</pre> | </pre> | ||
To clear another flag at the same time as V, use [[REP]]. | |||
=== See Also === | === See Also === | ||
* [[CLC]] | * [[CLC]] | ||
* [[CLRV]] | * [[CLRV]] | ||
* [[BIT]] | * [[BIT]] | ||
* [[BVC]] | * [[BVC]] | ||
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=== External Links === | === External Links === | ||
* [[Eyes & Lichty]] | * [[Eyes & Lichty]], [https://archive.org/details/0893037893ProgrammingThe65816/page/444 page 444] on CLV | ||
* [[Labiak]] | * [[Labiak]], [https://archive.org/details/Programming_the_65816/page/n143 page 133] on CLV | ||
* [[MCS6500 Manual]] | * 3.6.1 on [[MCS6500 Manual]], [https://archive.org/details/mos_microcomputers_programming_manual/page/n43 page 28] on CLV | ||
* [[Carr]] | * [[Carr]], [https://archive.org/details/6502UsersManual/page/n267 page 254] on CLV | ||
* [[Leventhal]] | * [[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 | * snes9x implementation of CLV: https://github.com/snes9xgit/snes9x/blob/master/cpuops.cpp#L1434 | ||
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