Integer Subtraction (sub)

sub{bwl} 	reg[8|16|32], r/m[8|16|32]
sub{bwl} 	r/m[8|16|32], reg[8|16|32]
sub{bwl} 	imm[8|16|32], r/m[8|16|32]

Operation

r/m[8|16|32] - reg[8|16|32] -> r/m[8|16|32]

reg[8|16|32] - r/m[8|16|32] -> reg[8|16|32]

r/m[8|16|32] - imm[8|16|32] -> r/m[8|16|32]

Description

Subtracts operand1 from operand2 and stores the result in operand2. When an immediate byte value is subtracted from a word, the immediate value is sign-extended to the size of the word operand before the subtract operation is executed.

If you wish to decimal adjust (das) or ASCII adjust (aas) the sub result, use the form of sub that stores the result in AL.

Example

Integer subtract the 8-bit constant, -126, from the content of the effective address (addressed by the ESI register plus an offset of 1):

subb $-126, 1(%esi)

Integer subtract the 16-bit constant, 1234, from the content of the effective address (addressed by the EDI register plus an offset of 4):

subw $1234, 4(%edi)

Integer subtract the 32-bit content of the EDX register from the effective address (addressed by the EDI register plus an offset of 4):

subl %edx, 4(%edi)