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ORA

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Basic Info
Addressing Mode Opcode Length Speed
Immediate 09 2/3 bytes 2 cycles*
Absolute 0D 3 bytes 4 cycles*
Absolute Long 0F 4 bytes 5 cycles*
Direct Page 05 2 bytes 3 cycles*
Direct Page Indirect 12 2 bytes 5 cycles*
Direct Page Indirect Long 07 2 bytes 6 cycles*
Absolute Indexed by X 1D 3 bytes 4 cycles*
Absolute Long Indexed by X 1F 4 bytes 5 cycles*
Absolute Indexed by Y 19 3 bytes 4 cycles*
Direct Page Indexed by X 15 2 bytes 4 cycles*
Direct Page Indexed Indirect by X 01 2 bytes 6 cycles*
Direct Page Indirect Indexed by Y 11 2 bytes 5 cycles*
Direct Page Indirect Long Indexed by Y 17 2 bytes 6 cycles*
Stack Relative 03 2 bytes 4 cycles*
Stack Relative Indirect Indexed by Y 13 2 bytes 7 cycles*
Flags Affected
N V M X D I Z C
N . . . . . Z .

ORA is a 65x instruction that performs a logical OR between the datum at the effective address and the accumulator and stores the disjunction in the accumulator. The size of the accumulator determines whether 8 or 16 bits are ORed.

Syntax

ORA #const
ORA addr
ORA long
ORA dp
ORA (dp)
ORA [dp]
ORA addr, X
ORA long, X
ORA addr, Y
ORA dp, X
ORA (dp, X)
ORA (dp), Y
ORA [dp], Y
ORA sr, S
ORA (sr, S), Y

Cycle Penalties

See Also

External Links