AND

From NES Hacker Wiki
Jump to: navigation, search
And Memory With Accumulator
Opcode: AND
Operation: A & M → A
Status Register: Status-List.png
Status-Change.pngStatus-Space.pngStatus-Change.pngStatus-Space.pngStatus-Ignore.pngStatus-Space.pngStatus-Ignore.pngStatus-Space.pngStatus-Ignore.pngStatus-Space.pngStatus-Ignore.png

AND (And Memory With Accumulator) performs a logical AND on the operand and the accumulator and stores the result in the accumulator. This opcode is similar in function to ORA and EOR.

Operation

This pseudo C code shows how the AND opcode functions when it is executed.

Operand &= ACCUMULATOR        // AND the two values together.
SET_NEGATIVE(Operand);        // Clears the Negative Flag if the Operand is $#00-7F, otherwise sets it.
SET_ZERO(Operand);            // Sets the Zero Flag if the Operand is $#00, otherwise clears it.
ACCUMULATOR = Operand;        // Stores the Operand in the Accumulator Register.

Addressing Modes

Addressing Mode Assembly Language Form Opcode # Bytes # Cycles
Immediate AND #Operand 29 2 2
Zero Page AND Operand 25 2 3
Zero Page, X AND Operand, X 35 2 4
Absolute AND Operand 2D 3 4
Absolute, X AND Operand, X 3D 3 4*
Absolute, Y AND Operand, Y 39 3 4*
(Indirect, X) AND (Operand, X) 21 2 6
(Indirect), Y AND (Operand), Y 31 2 5*
* Add 1 if page boundary is crossed.

Examples