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DEY: Difference between revisions
From SnesLab
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'''DEY''' is a 65x instruction that decrements the [[Y index register]] by one. DEY ignores the [[decimal flag]]. | '''DEY''' is a 65x instruction that decrements the [[Y index register]] by one. DEY ignores the [[decimal flag]]. Unlike [[SBC]], DEY never affects the [[carry flag]]. | ||
==== Syntax ==== | ==== Syntax ==== | ||
Latest revision as of 20:09, 12 August 2024
| Basic Info | |||||||
|---|---|---|---|---|---|---|---|
| Addressing Mode | Opcode | Length | Speed | ||||
| Implied (type 1) | 88 | 1 byte | 2 cycles | ||||
| Flags Affected | |||||||
|---|---|---|---|---|---|---|---|
| N | V | M | X | D | I | Z | C |
| N | . | . | . | . | . | Z | . |
DEY is a 65x instruction that decrements the Y index register by one. DEY ignores the decimal flag. Unlike SBC, DEY never affects the carry flag.
Syntax
DEY
See Also
External Links
- Eyes & Lichty, page 453 on DEY
- Labiak, page 140 on DEY
- 7.7 on MCS6500 Manual, page 98 on DEY
- Carr, page 258 on DEY
- Leventhal, page 3-62 on DEY
- snes9x implementation of DEY: https://github.com/snes9xgit/snes9x/blob/master/cpuops.cpp#L1514
- Clark, Bruce. http://www.6502.org/tutorials/65c816opcodes.html#6.1.1.3