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SEC: Difference between revisions
From SnesLab
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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) | ||
|38 | |38 | ||
|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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|1 | |1 | ||
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'''SEC''' is a 65x instruction that sets the [[carry flag]]. | |||
Similar to doing a [[CLC]] before an [[ADC]], it is recommended to run SEC (or otherwise make sure the carry flag is set) before running a [[SBC]] so that the difference is correct. | |||
No other flags are affected. | |||
==== Syntax ==== | |||
<pre> | |||
SEC | |||
</pre> | |||
=== See Also === | === See Also === | ||
* [[CLC]] | * [[CLC]] | ||
* [[XCE]] | |||
* [[SED]] | |||
* [[SEI]] | |||
* [[SEP]] | |||
=== External Links === | === External Links === | ||
* [[Eyes & Lichty]] | * [[Eyes & Lichty]], [https://archive.org/details/0893037893ProgrammingThe65816/page/499 page 499] on SEC | ||
* [[Labiak]] | * [[Labiak]], [https://archive.org/details/Programming_the_65816/page/n190 page 180] on SEC | ||
* [[MCS6500 Manual]] | * 3.0.1 on [[MCS6500 Manual]], [https://archive.org/details/mos_microcomputers_programming_manual/page/n39 page 24] on SEC | ||
* [[Carr]] page on SEC | * [[Carr]], [https://archive.org/details/6502UsersManual/page/n285 page 272] on SEC | ||
* [[Leventhal]], [https://archive.org/details/6502-assembly-language-programming/page/n142 page 3-93] on SEC | |||
* snes9x implementation of SEC: https://github.com/snes9xgit/snes9x/blob/master/cpuops.cpp#L1427 | |||
* Clark, Bruce. http://www.6502.org/tutorials/65c816opcodes.html#6.4.1 | |||
[[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 23:07, 8 August 2024
| Basic Info | |||||||
|---|---|---|---|---|---|---|---|
| Addressing Mode | Opcode | Length | Speed | ||||
| Implied (type 2) | 38 | 1 byte | 2 cycles | ||||
| Flags Affected | ||||||||
|---|---|---|---|---|---|---|---|---|
| N | V | M | X | D | I | Z | C | |
| . | . | . | . | . | . | . | 1 | |
SEC is a 65x instruction that sets the carry flag.
Similar to doing a CLC before an ADC, it is recommended to run SEC (or otherwise make sure the carry flag is set) before running a SBC so that the difference is correct.
No other flags are affected.
Syntax
SEC
See Also
External Links
- Eyes & Lichty, page 499 on SEC
- Labiak, page 180 on SEC
- 3.0.1 on MCS6500 Manual, page 24 on SEC
- Carr, page 272 on SEC
- Leventhal, page 3-93 on SEC
- snes9x implementation of SEC: https://github.com/snes9xgit/snes9x/blob/master/cpuops.cpp#L1427
- Clark, Bruce. http://www.6502.org/tutorials/65c816opcodes.html#6.4.1