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PHY: Difference between revisions
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'''PHY''' is a [[65c816]] instruction that pushes the value of the [[Y index register]] onto the [[stack]]. If Y is 16 bits wide, the high byte is pushed first. | '''PHY''' is a [[65c816]] instruction that pushes the value of the [[Y index register]] onto the [[stack]]. If Y is 16 bits wide, the high byte is pushed first. | ||
The [[stack pointer]] is decremented by the number of bytes Y is. | |||
No flags are affected. | No flags are affected. | ||
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==== Cycle Penalty ==== | |||
* PHY takes one additional cycle if the index registers are 16 bits wide. | * PHY takes one additional cycle if the index registers are 16 bits wide. | ||
Latest revision as of 00:05, 17 August 2024
| Basic Info | |||||||
|---|---|---|---|---|---|---|---|
| Addressing Mode | Opcode | Length | Speed | ||||
| Stack (Push) | 5A | 1 byte | 3 cycles* | ||||
| Flags Affected | ||||||||
|---|---|---|---|---|---|---|---|---|
| N | V | M | X | D | I | Z | C | |
| . | . | . | . | . | . | . | . | |
PHY is a 65c816 instruction that pushes the value of the Y index register onto the stack. If Y is 16 bits wide, the high byte is pushed first.
The stack pointer is decremented by the number of bytes Y is.
No flags are affected.
Syntax
PHY
Cycle Penalty
- PHY takes one additional cycle if the index registers are 16 bits wide.
See Also
External Links
- Eyes & Lichty, page 482 on PHY
- Labiak, page 166 on PHY
- snes9x implementation of PHY: https://github.com/snes9xgit/snes9x/blob/master/cpuops.cpp#L1921