ORA - OR Accumulator with memory

ORA performs a bitwise logical OR of the value in the accumulator with that of the memory location with the result stored in the accumulator.

The result will be each bit in the accumulator will be set if either the same bit in the original accumulator value and the memory are set.

For 8-bit processors n has the value of bit 7 and v the value of bit 6 of the memory location.

For 16-bit processors, when m=0, n has the value of bit 15 and v the value of bit 14 of the memory location.

Second it performs a logical AND of the memory and the accumulator. If the result is zero the z flag is set.

In both operations, the contents of the accumulator and memory are not modified.

Flags

Set if most significant bit of result is set

Set if result is zero, otherwise clear

Syntax	Opcode	Available on:			# of	# of	Addressing Mode
Syntax	(hex)	6502	65C02	65816	bytes	cycles	Addressing Mode
ORA #const	09	x	x	x	2¹	2²	Immediate
ORA addr	0D	x	x	x	3	4²	Absolute
ORA long	0F			x	4	5²	Absolute Long
ORA dp	05	x	x	x	2	3^{2, 3}	Direct Page
ORA (dp)	12		x	x	2	5^{2, 3}	Direct Page Indirect
ORA [dp]	07			x	2	6^{2, 3}	Direct Page Indirect Long
ORA addr,X	1D	x	x	x	3	4^{2, 4}	Absolute Indexed X
ORA long,X	1F			x	4	5²	Absolute Long Indexed X
ORA addr,Y	19	x	x	x	3	4^{2, 4}	Absolute Indexed Y
ORA dp,X	15	x	x	x	2	4^{2, 3}	Direct Page Indexed X
ORA (dp,X)	01	x	x	x	2	6^{2, 3}	Direct Page Indexed Indirect X
ORA (dp),Y	11	x	x	x	2	5^{2, 3, 4}	Direct Page Indirect Indexed Y
ORA [dp],Y	17			x	2	6^{2, 3}	Direct Page Indirect Long Indexed Y
ORA sr,S	03			x	2	4²	Stack Relative
ORA (sr,S),Y	13			x	2	7²	Stack Relative Indirect Indexed Y

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