LSR: Difference between revisions

Revision as of 20:44, 17 May 2023

LSR (Logical Shift Right) is a 65x instruction that shifts a value one bit to the right (division by two). The most significant bit becomes a zero. The least significant bit is shifted into the carry flag.


Basic Info
Addressing Mode	Opcode	Length	Speed
accumulator	4A	1 byte	2 cycles
absolute	4E	3 bytes	6 cycles
direct page	46	2 bytes	5 cycles
absolute indexed X	5E	3 bytes	7 cycles
direct page indexed X	56	2 bytes	6 cycles


Flags Clobbered
N	V	M	X	D	I	Z	C
0	.	.	.	.	.

External Links

Eyes & Lichty page on LSR: https://archive.org/details/0893037893ProgrammingThe65816/page/n491
Labiak page on LSR: https://archive.org/details/Programming_the_65816/page/n162
MCS6500 Manual page on LSR: https://archive.org/details/mos_microcomputers_programming_manual/page/n169
Carr page on LSR: https://archive.org/details/6502UsersManual/page/n278
Leventhal page on LSR: https://archive.org/details/6502-assembly-language-programming/page/n125
snes9x implementation of LSR: https://github.com/snes9xgit/snes9x/blob/master/cpuops.cpp#L862

@@ Line 63: / Line 63: @@
 * [[Carr]] page on LSR: https://archive.org/details/6502UsersManual/page/n278
 * [[Leventhal]] page on LSR: https://archive.org/details/6502-assembly-language-programming/page/n125
+* snes9x implementation of LSR: https://github.com/snes9xgit/snes9x/blob/master/cpuops.cpp#L862
 [[Category:ASM]]