Truth tables for logic operations

Truth table for "NOT"

A	Result
0	1
1	0

A bit-wise NOT operation performs the logical NOT operation on each bit of the input.

i.e.
bit 7_result = NOT bit 7_input ,
bit 6_result = NOT bit 6_input ...

For the 8-bit value 10110011 (base 2), this table shows the computation:

	Bit
	7	6	5	4	3	2	1	0
Input	1	0	1	1	0	0	1	1
Result	0	1	0	0	1	1	0	0

An example in Z80 assembler:

ld a,%10110011        ;; load value into A register
not                   ;; perform bit-wise logical NOT operation on all bits of register A

Truth table for "AND"

A	B	Result
0	0	0
0	1	0
1	0	0
1	1	1

A bit-wise AND operation performs the logical AND operation on each bit position of the input values.

i.e.
bit 7_result = bit 7_{input A} AND bit 7_{input B} ,
bit 6_result = bit 6_{input A} AND bit 6_{input B} ...

For two 8-bit values: inputA = 10110011 (base 2), inputB = 11101010, this table shows the computation:

	Bit
	7	6	5	4	3	2	1	0
Input A	1	0	1	1	0	0	1	1
Input B	1	1	1	0	1	0	1	0
Result	1	0	1	0	0	0	1	0

An example in Z80 assembler:

ld a,%10110011        ;; load input A into A register
ld b,%11101010        ;; load input B into B register
and a,b               ;; A = A AND B (each bit of A is logically ANDed with each bit in B
                      ;; and the result is stored back into A)

Truth table for "OR"

A	B	Result
0	0	0
0	1	1
1	0	1
1	1	1

A bit-wise OR operation performs the logical OR operation on each bit position of the input values.

i.e.
bit 7_result = bit 7_{input A} OR bit 7_{input B} ,
bit 6_result = bit 6_{input A} OR bit 6_{input B} ...

For two 8-bit values: inputA = 10110011 (base 2), inputB = 11101010, this table shows the computation:

	Bit
	7	6	5	4	3	2	1	0
Input A	1	0	1	1	0	0	1	1
Input B	1	1	1	0	1	0	1	0
Result	1	1	1	1	1	0	1	1

An example in Z80 assembler:

ld a,%10110011        ;; load input A into A register
ld b,%11101010        ;; load input B into B register
or a,b                ;; A = A OR B (each bit of A is logically ORed with each bit in B
                      ;; and the result is stored back into A)

Truth table for "Exclusive-OR (XOR/EOR)"

A	B	Result
0	0	0
0	1	1
1	0	1
1	1	0

A bit-wise XOR operation performs the logical XOR operation on each bit position of the input values.

i.e.
bit 7_result = bit 7_{input A} XOR bit 7_{input B} ,
bit 6_result = bit 6_{input A} XOR bit 6_{input B} ...

For two 8-bit values: inputA = 10110011 (base 2), inputB = 11101010, this table shows the computation:

	Bit
	7	6	5	4	3	2	1	0
Input A	1	0	1	1	0	0	1	1
Input B	1	1	1	0	1	0	1	0
Result	0	1	0	1	1	0	0	1

An example in Z80 assembler:

ld a,%10110011        ;; load input A into A register
ld b,%11101010        ;; load input B into B register
xor a,b               ;; A = A XOR B (each bit of A is logically Exclusive-ORed with each bit in B
                      ;; and the result is stored back into A)