We've just updated MediaWiki and its underlying software. If anything doesn't look or work quite right, please mention it to us. --RanAS

ROL: Difference between revisions

From SnesLab
Jump to: navigation, search
(added group 2 category)
(→‎See Also: spc700)
 
(28 intermediate revisions by the same user not shown)
Line 1: Line 1:
'''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.
{| class="wikitable" style="float:right;clear:right;width:40%"
 
{| class="wikitable" style="float:right;clear:right;width:30%"
!colspan="8"|Basic Info
!colspan="8"|Basic Info
|+
|+
Line 9: Line 7:
|'''Speed'''
|'''Speed'''
|+
|+
|accumulator
|[[Accumulator Addressing|Accumulator]]
|2A
|2A
|1 byte
|1 byte
|2 cycles
|2 cycles
|+
|+
|absolute
|[[Absolute]]
|2E
|2E
|3 bytes
|3 bytes
|6 cycles
|6 cycles*
|+
|+
|direct page
|[[Direct Page Addressing|Direct Page]]
|26
|26
|2 bytes
|2 bytes
|5 cycles
|5 cycles*
|+
|+
|absolute indexed by X
|absolute indexed by X
|3E
|3E
|3 bytes
|3 bytes
|7 cycles
|7 cycles*
|+
|+
|direct page indexed by X
|direct page indexed by X
|36
|36
|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 Clobbered
!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]]
|+
|+
|
|
Line 56: Line 54:
|
|
|}
|}
'''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. 
===== Cycle Penalties =====
* 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.
[[File:rol.png]]


=== See Also ===
=== See Also ===
* [[ROR]]
* [[ROR]]
* [[ROL (SPC700)]]
* [[ROL (Super FX)]]
=== External Links ===
* [[Eyes & Lichty]] page 490, on ROL: https://archive.org/details/0893037893ProgrammingThe65816/page/n516
* lbid page 190 before & after diagram of ROL: https://archive.org/details/0893037893ProgrammingThe65816/page/n216
* [[Labiak]] page 174 on ROL: https://archive.org/details/Programming_the_65816/page/n184
* [[MCS6500 Manual]] page 149 on ROL: https://archive.org/details/mos_microcomputers_programming_manual/page/n170
* [[Carr]] page 269 on ROL: https://archive.org/details/6502UsersManual/page/n282
* [[Leventhal]] page 3-85 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


[[Category:ASM]]
[[Category:ASM]]
[[Category:Group Two Instructions]]
[[Category:Group Two Instructions]]
[[Category:Read-Modify-Write Instructions]]
[[Category:Inherited from 6502]]

Latest revision as of 19:24, 8 January 2024

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.

Cycle Penalties

rol.png

See Also

External Links

Retrieved from "https://sneslab.net/mw/index.php?title=ROL&oldid=13797"