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SEC: Difference between revisions
From SnesLab
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(→See Also: SEP) |
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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. | 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 ==== | ==== Syntax ==== | ||
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* [[SED]] | * [[SED]] | ||
* [[SEI]] | * [[SEI]] | ||
* [[SEP]] | |||
=== External Links === | === External Links === | ||
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