of Microprocessors

Table 5-1. 6502 Instruction Set Listing
Instruction Addressing Modes' Function Flags
IMM ABS ZPG Z,X Z,Y A,X A,Y I,X I,Y ACC2 REL
LDA 2 4 3 4 4 4 6 5 Load A NZ
STA 4 3 4 5 5 6 6 Store A
LDX 2 4 3 4 4 Load index X NZ
LDY 2 4 3 4 4 Load index Y NZ
STX 4 3 4 Store index X
STY 4 3 4 Store index Y
ADC 2 4 3 4 4 4 6 5 Add to A with carry NZVC
SBC 2 4 3 4 4 4 6 5 Subtract from A w/carry NZ VC
AND 2 4 3 4 4 4 6 5 And to A NZ
ORA 2 4 3 4 4 4 6 5 Logical or to A NZ
EOR 2 4 3 4 4 4 6 5 Exclusive or to A NZ
CMP 2 4 3 4 4 4 6 5 Compare with A NZC
CPX 2 4 3 Compare with X
CPY 2 4 3 Compare with Y
INC DEC 6 5 6 7 Increment, decrement NZ
INXINY 2 Increment X and Y NZ
DEX DEY 2 Decrement X and Y NZ
ASL LSR 6 5 7 6 2 Shift left or right NZ C
ROL ROR 6 5 7 6 2 Rotate left or right NZ C
BxS BxC 2 Branch conditionally
on any flag
CLx SEx 2 Set or clear any flag Note 3
JMP 3 5 Jump unconditionally
JSR 6 Jump to subroutine Note 4
RTS RTI 6 Return from subroutine NoteS
PHA PHP 3 Push A, push status
PLA PLP 4 Pull A, pull status Note 6
TXA TXA 2 Transfer index to A NZ
TAX TAY 2 Transfer A to index NZ
TXS 2 X to stack pointer
TSX 2 Stack pointer to X NZ
NOP 2 No operation
Notes:
1 Numbers in this column are execution times with a 1-MHz clOCk. 4 Jump to subroutine does not save the flags; however, an interrupt does save
2 Accumulator addressing mode also covers implied addressing. them.
3 Flags that may be set or cleared directly are: carry, overflow, interrupt enable, decimal 5 Return from interrupt restores the flags.
mode. 6 PLA sets Nand Z flags; PLP loads status from the stack.