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ROR: Difference between revisions
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{| class="wikitable" style="float:right;clear:right;width:40%" | |||
{| class="wikitable" style="float:right;clear:right;width: | |||
!colspan="8"|Basic Info | !colspan="8"|Basic Info | ||
|+ | |+ | ||
Line 9: | Line 7: | ||
|'''Speed''' | |'''Speed''' | ||
|+ | |+ | ||
| | |[[Accumulator Addressing|Accumulator]] | ||
|6A | |6A | ||
|1 byte | |1 byte | ||
|2 cycles | |2 cycles | ||
|+ | |+ | ||
| | |[[Absolute]] | ||
|6E | |6E | ||
|3 bytes | |3 bytes | ||
|6 cycles | |6 cycles* | ||
|+ | |+ | ||
| | |[[Direct Page Addressing|Direct Page]] | ||
|66 | |66 | ||
|2 bytes | |2 bytes | ||
|5 cycles | |5 cycles* | ||
|+ | |+ | ||
|absolute indexed by X | |absolute indexed by X | ||
|7E | |7E | ||
|3 bytes | |3 bytes | ||
|7 cycles | |7 cycles* | ||
|+ | |+ | ||
|direct page indexed by X | |direct page indexed by X | ||
|76 | |76 | ||
|2 bytes | |2 bytes | ||
|6 cycles | |6 cycles* | ||
|} | |} | ||
{| class="wikitable" style="float:right;clear:right;width:30%" | {| class="wikitable" style="float:right;clear:right;width:30%" | ||
!colspan="9"|Flags | !colspan="9"|Flags Affected | ||
|+ | |+ | ||
|N | |[[N Flag|N]] | ||
|V | |[[V Flag|V]] | ||
|M | |[[M Flag|M]] | ||
|X | |[[X Flag|X]] | ||
|D | |[[D Flag|D]] | ||
|I | |[[I Flag|I]] | ||
|Z | |[[Z Flag|Z]] | ||
|C | |[[C Flag|C]] | ||
|+ | |+ | ||
| | | | ||
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|} | |} | ||
'''ROR''' (Rotate Right) is a 65x instruction that rotates a value and the [[carry flag]] right one bit. The least significant bit is shifted into the carry flag. The carry flag is shifted into the most significant bit. | |||
===== Cycle Penalties ===== | |||
* Except in [[accumulator addressing]], ROR takes two extra cycles when the accumulator is 16 bits wide. | |||
* In [[direct page addressing]] modes, ROR takes another extra cycle if the low byte of the [[direct page register]] is nonzero. | |||
=== See Also === | === See Also === | ||
* [[ROL]] | * [[ROL]] | ||
* [[ROR (SPC700)]] | |||
* [[ROR (Super FX)]] | |||
=== External Links === | |||
* [[Eyes & Lichty]] page 491, on ROR: https://archive.org/details/0893037893ProgrammingThe65816/page/n517 | |||
* lbid, page 191, before & after diagram on ROR: https://archive.org/details/0893037893ProgrammingThe65816/page/n217 | |||
* [[Labiak]] page 175 on ROR: https://archive.org/details/Programming_the_65816/page/n185 | |||
* [[MCS6500 Manual]] page 150 on ROR: https://archive.org/details/mos_microcomputers_programming_manual/page/n171 | |||
* [[Carr]] page 269 on ROR: https://archive.org/details/6502UsersManual/page/n282 | |||
* [[Leventhal]] page 3-87 on ROR: https://archive.org/details/6502-assembly-language-programming/page/n136 | |||
* snes9x implementation of ROR: https://github.com/snes9xgit/snes9x/blob/master/cpuops.cpp#L1070 | |||
* undisbeliever on ROR: https://undisbeliever.net/snesdev/65816-opcodes.html#ror-rotate-right | |||
[[Category:ASM]] | [[Category:ASM]] |
Revision as of 19:24, 8 January 2024
Basic Info | |||||||
---|---|---|---|---|---|---|---|
Addressing Mode | Opcode | Length | Speed | ||||
Accumulator | 6A | 1 byte | 2 cycles | ||||
Absolute | 6E | 3 bytes | 6 cycles* | ||||
Direct Page | 66 | 2 bytes | 5 cycles* | ||||
absolute indexed by X | 7E | 3 bytes | 7 cycles* | ||||
direct page indexed by X | 76 | 2 bytes | 6 cycles* |
Flags Affected | ||||||||
---|---|---|---|---|---|---|---|---|
N | V | M | X | D | I | Z | C | |
. | . | . | . | . |
ROR (Rotate Right) is a 65x instruction that rotates a value and the carry flag right one bit. The least significant bit is shifted into the carry flag. The carry flag is shifted into the most significant bit.
Cycle Penalties
- Except in accumulator addressing, ROR takes two extra cycles when the accumulator is 16 bits wide.
- In direct page addressing modes, ROR takes another extra cycle if the low byte of the direct page register is nonzero.
See Also
External Links
- Eyes & Lichty page 491, on ROR: https://archive.org/details/0893037893ProgrammingThe65816/page/n517
- lbid, page 191, before & after diagram on ROR: https://archive.org/details/0893037893ProgrammingThe65816/page/n217
- Labiak page 175 on ROR: https://archive.org/details/Programming_the_65816/page/n185
- MCS6500 Manual page 150 on ROR: https://archive.org/details/mos_microcomputers_programming_manual/page/n171
- Carr page 269 on ROR: https://archive.org/details/6502UsersManual/page/n282
- Leventhal page 3-87 on ROR: https://archive.org/details/6502-assembly-language-programming/page/n136
- snes9x implementation of ROR: https://github.com/snes9xgit/snes9x/blob/master/cpuops.cpp#L1070
- undisbeliever on ROR: https://undisbeliever.net/snesdev/65816-opcodes.html#ror-rotate-right