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CPY: Difference between revisions
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=== External Links === | === External Links === | ||
* [[Eyes & Lichty]] page 450, on CPY: https://archive.org/details/0893037893ProgrammingThe65816/page/ | * [[Eyes & Lichty]] page 450, on CPY: https://archive.org/details/0893037893ProgrammingThe65816/page/450 | ||
* [[Labiak]] page 137 on CPY: https://archive.org/details/Programming_the_65816/page/n147 | * [[Labiak]] page 137 on CPY: https://archive.org/details/Programming_the_65816/page/n147 | ||
* [[MCS6500 Manual]] page 99 on CPY: https://archive.org/details/mos_microcomputers_programming_manual/page/n117 | * [[MCS6500 Manual]] page 99 on CPY: https://archive.org/details/mos_microcomputers_programming_manual/page/n117 |
Revision as of 10:46, 15 July 2024
Basic Info | |||||||
---|---|---|---|---|---|---|---|
Addressing Mode | Opcode | Length | Speed | ||||
Immediate | C0 | 2/3 bytes | 2 cycles* | ||||
Absolute | CC | 3 bytes | 4 cycles* | ||||
Direct Page | C4 | 2 bytes | 3 cycles* |
Flags Affected | ||||||||
---|---|---|---|---|---|---|---|---|
N | V | M | X | D | I | Z | C | |
. | . | . | . | . |
CPY (Compare Y) is a 65x instruction that compares the value of the Y index register. Internally, this is done via a subtraction, but the difference is not stored anywhere. The contents at the effective address and the Y index register both remain unchanged.
CPY assumes its operands are unsigned.
Syntax
CPY #const CPY addr CPY dp
See Also
External Links
- Eyes & Lichty page 450, on CPY: https://archive.org/details/0893037893ProgrammingThe65816/page/450
- Labiak page 137 on CPY: https://archive.org/details/Programming_the_65816/page/n147
- MCS6500 Manual page 99 on CPY: https://archive.org/details/mos_microcomputers_programming_manual/page/n117
- Carr page 257 on CPY: https://archive.org/details/6502UsersManual/page/n270
- Leventhal page 3-59 on CPY: https://archive.org/details/6502-assembly-language-programming/page/n108
- snes9x implementation of CPY: https://github.com/snes9xgit/snes9x/blob/master/cpuops.cpp#L442
- undisbeliever on CPY: https://undisbeliever.net/snesdev/65816-opcodes.html#cpy-compare-index-register-y-with-memory