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STY: Difference between revisions
From SnesLab
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Revision as of 04:05, 20 November 2023
| Basic Info | |||||||
|---|---|---|---|---|---|---|---|
| Addressing Mode | Opcode | Length | Speed | ||||
| Absolute | 8C | 3 bytes | 4 cycles* | ||||
| direct page | 84 | 2 bytes | 3 cycles* | ||||
| direct page indexed Y | 96 | 2 bytes | 4 cycles* | ||||
| Flags Affected | ||||||||
|---|---|---|---|---|---|---|---|---|
| N | V | M | X | D | I | Z | C | |
| . | . | . | . | . | . | . | . | |
STY (Store Y) is a 65x instruction that stores the value of the Y index register. STY takes one additional cycle when the index registers are 16 bits wide, in all addressing modes. In both direct page addressing modes only, STY takes another additional cycle if the low byte of the direct page register is nonzero.
See Also
External Links
- Eyes & Lichty page on STY: https://archive.org/details/0893037893ProgrammingThe65816/page/n532
- Labiak page on STY: https://archive.org/details/Programming_the_65816/page/n197
- MCS6500 Manual page on STY: https://archive.org/details/mos_microcomputers_programming_manual/page/n115
- Carr page on STY: https://archive.org/details/6502UsersManual/page/n287
- Leventhal page on STY: https://archive.org/details/6502-assembly-language-programming/page/n147
- snes9x implementation of STY: https://github.com/snes9xgit/snes9x/blob/master/cpuops.cpp#L1302
- undisbeliever on STY: https://undisbeliever.net/snesdev/65816-opcodes.html#sty-store-index-register-y-to-memory