NOT perform the bitwise complement of operand and stores the result back into operand itself.
NOT BX ;Complement contents of BX register. – DX =F038h
NOT DX ;after the instruction DX = 0FC7h
AND Instruction – AND corresponding bits of two operands
This Performs a bitwise Logical AND of two operands. The result of the operation is stored in the op1 and used to set the flags. AND op1, op2 To perform a bitwise AND of the two operands, each bit of the result is set to 1 if and only if the corresponding bit in both of the operands is 1, otherwise the bit in the result I cleared to 0 .
AND BH, CL ;AND byte in CL with byte in BH ;result in BH
AND BX,00FFh ;AND word in BX with immediate 00FFH. Mask upper byte, leave lower unchanged
AND CX,[SI] ; AND word at offset [SI] in data segment with word in CX register . Result in CX register and BX = 10110011 01011110
AND BX,00FFh ;Mask out upper 8 bits of BX. ;Result BX = 00000000 01011110 and CF =0 , OF = 0, PF = 0, SF = 0 ,ZF = 0.
OR Instruction – Logically OR corresponding of two operands
OR Instruction – OR instruction perform the bit wise logical OR of two operands .Each bit of the result is cleared to 0 if and only if both corresponding bits in each operand are 0, other wise the bit in the result is set to 1.
Syntax–- OR destination, source.
OR AH, CL ;CL is OR’ed with AH, result in AH.
;CX = 00111110 10100101
OR CX,FF00h ;OR CX with immediate FF00h result in CX = 11111111 10100101
;Upper byte are all 1’s lower bytes are unchanged.
XOR Instruction – Exclusive XOR destination, source
XOR Instruction – XOR performs a bit wise logical XOR of the operands specified by op1 and op2. The result of the operand is stored in op1 and is used to set the flag.
Syntax–- XOR destination, source.
Example : ( Numerical )
; BX = 00111101 01101001 and CX = 00000000 11111111
XOR BX, CX ;Exclusive OR CX with BX and Result BX = 00111101 10010110
TEST Instruction – AND operand to update flags
TEST Instruction – This instruction ANDs the contents of a source byte or word with the contents of specified destination word. Flags are updated but neither operand is changed . TEST instruction is often used to set flags before a condition jump instruction
TEST AL, BH ;AND BH with AL. no result is stored . Update PF, SF, ZF TEST CX, 0001H ;AND CX with immediate number
;no result is stored, Update PF,SF
;AL = 01010001
TEST Al, 80H ;AND immediate 80H with AL to test f MSB of AL is 1 or 0
;ZF = 1 if MSB of AL = 0 and AL = 01010001 (unchanged),PF = 0 , SF = 0,
;ZF = 1 because ANDing produced is 00