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CPX: Difference between revisions
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|[[Immediate]] | |[[Immediate]] | ||
|E0 | |E0 | ||
|2 bytes | |2 bytes* | ||
|2 cycles | |2 cycles* | ||
|+ | |+ | ||
|[[Absolute]] | |[[Absolute]] | ||
|EC | |EC | ||
|3 bytes | |3 bytes | ||
|4 cycles | |4 cycles* | ||
|+ | |+ | ||
| | |[[Direct Page Addressing|Direct Page]] | ||
|E4 | |E4 | ||
|2 bytes | |2 bytes | ||
|3 cycles | |3 cycles* | ||
|} | |} | ||
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!colspan="9"|Flags Affected | !colspan="9"|Flags Affected | ||
|+ | |+ | ||
|N | |[[Negative Flag|N]] | ||
|V | |[[Overflow Flag|V]] | ||
|M | |[[M Flag|M]] | ||
|X | |[[X Flag|X]] | ||
|D | |[[Decimal Flag|D]] | ||
|I | |[[I Flag|I]] | ||
|Z | |[[Zero Flag|Z]] | ||
|C | |[[Carry Flag|C]] | ||
|+ | |+ | ||
| | | | ||
| Line 45: | Line 45: | ||
|} | |} | ||
'''CPX''' (Compare X) is a 65x instruction that compares the value of the [[X index register]]. | '''CPX''' (Compare X) is a 65x instruction that compares the value of the [[X index register]]. Internally, this is done via a subtraction, but the difference is not stored anywhere. The contents at the effective address and the X index register both remain unchanged. | ||
CPX assumes its operands are unsigned. | |||
=== See Also === | === See Also === | ||
| Line 52: | Line 54: | ||
=== External Links === | === External Links === | ||
* [[Eyes & Lichty]] page on CPX: https://archive.org/details/0893037893ProgrammingThe65816/page/n475 | * [[Eyes & Lichty]] page 449, on CPX: https://archive.org/details/0893037893ProgrammingThe65816/page/n475 | ||
* [[Labiak]] page on CPX: https://archive.org/details/Programming_the_65816/page/n146 | * [[Labiak]] page 136 on CPX: https://archive.org/details/Programming_the_65816/page/n146 | ||
* [[MCS6500 Manual]] page on CPX: https://archive.org/details/mos_microcomputers_programming_manual/page/n117 | * [[MCS6500 Manual]] page 99 on CPX: https://archive.org/details/mos_microcomputers_programming_manual/page/n117 | ||
* [[Carr]] page on CPX: https://archive.org/details/6502UsersManual/page/n269 | * [[Carr]] page 256 on CPX: https://archive.org/details/6502UsersManual/page/n269 | ||
* [[Leventhal]] page on CPX: https://archive.org/details/6502-assembly-language-programming/page/n107 | * [[Leventhal]] page 3-58 on CPX: https://archive.org/details/6502-assembly-language-programming/page/n107 | ||
* snes9x implementation of CPX: https://github.com/snes9xgit/snes9x/blob/master/cpuops.cpp#L402 | * snes9x implementation of CPX: https://github.com/snes9xgit/snes9x/blob/master/cpuops.cpp#L402 | ||
* undisbeliever on CPX: https://undisbeliever.net/snesdev/65816-opcodes.html#cpx-compare-index-register-x-with-memory | * undisbeliever on CPX: https://undisbeliever.net/snesdev/65816-opcodes.html#cpx-compare-index-register-x-with-memory | ||
Latest revision as of 07:51, 19 December 2023
| Basic Info | |||||||
|---|---|---|---|---|---|---|---|
| Addressing Mode | Opcode | Length | Speed | ||||
| Immediate | E0 | 2 bytes* | 2 cycles* | ||||
| Absolute | EC | 3 bytes | 4 cycles* | ||||
| Direct Page | E4 | 2 bytes | 3 cycles* | ||||
| Flags Affected | ||||||||
|---|---|---|---|---|---|---|---|---|
| N | V | M | X | D | I | Z | C | |
| . | . | . | . | . | ||||
CPX (Compare X) is a 65x instruction that compares the value of the X index register. Internally, this is done via a subtraction, but the difference is not stored anywhere. The contents at the effective address and the X index register both remain unchanged.
CPX assumes its operands are unsigned.
See Also
External Links
- Eyes & Lichty page 449, on CPX: https://archive.org/details/0893037893ProgrammingThe65816/page/n475
- Labiak page 136 on CPX: https://archive.org/details/Programming_the_65816/page/n146
- MCS6500 Manual page 99 on CPX: https://archive.org/details/mos_microcomputers_programming_manual/page/n117
- Carr page 256 on CPX: https://archive.org/details/6502UsersManual/page/n269
- Leventhal page 3-58 on CPX: https://archive.org/details/6502-assembly-language-programming/page/n107
- snes9x implementation of CPX: https://github.com/snes9xgit/snes9x/blob/master/cpuops.cpp#L402
- undisbeliever on CPX: https://undisbeliever.net/snesdev/65816-opcodes.html#cpx-compare-index-register-x-with-memory