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ROL
From SnesLab
| Basic Info | |||||||
|---|---|---|---|---|---|---|---|
| Addressing Mode | Opcode | Length | Speed | ||||
| Accumulator | 2A | 1 byte | 2 cycles | ||||
| Absolute | 2E | 3 bytes | 6 cycles* | ||||
| Direct Page | 26 | 2 bytes | 5 cycles* | ||||
| absolute indexed by X | 3E | 3 bytes | 7 cycles* | ||||
| direct page indexed by X | 36 | 2 bytes | 6 cycles* | ||||
| Flags Affected | ||||||||
|---|---|---|---|---|---|---|---|---|
| N | V | M | X | D | I | Z | C | |
| . | . | . | . | . | ||||
ROL (Rotate Left) is a 65x instruction that rotates a value and the carry flag left one bit. The most significant bit is shifted into the carry flag. The carry flag is shifted into the least significant bit. Except in accumulator addressing, ROL takes two extra cycles when the accumulator is 16 bits wide. In direct page addressing modes, ROL takes another extra cycle if the low byte of the direct page register is nonzero.
See Also
External Links
- Eyes & Lichty page 490, on ROL: https://archive.org/details/0893037893ProgrammingThe65816/page/n516
- Labiak page on ROL: https://archive.org/details/Programming_the_65816/page/n184
- MCS6500 Manual page on ROL: https://archive.org/details/mos_microcomputers_programming_manual/page/n170
- Carr page on ROL: https://archive.org/details/6502UsersManual/page/n282
- Leventhal page on ROL: https://archive.org/details/6502-assembly-language-programming/page/n134
- snes9x implementation of ROL: https://github.com/snes9xgit/snes9x/blob/master/cpuops.cpp#L1011
- undisbeliever on ROL: https://undisbeliever.net/snesdev/65816-opcodes.html#rol-rotate-left