Integer Subtraction With Borrow (sbb)

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

Operation

r/m[8|16|32] - (reg[8|16|32] + CF) -> r/m[8|16|32]

reg[8|16|32] - (r/m[8|16|32] + CF) -> reg[8|16|32]

r/m[8|16|32] - (imm[8|16|32] + CF) -> r/m[8|16|32]

Description

Subtracts (operand1 and the carry flag) 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.

Example

Integer subtract the 8-bit content of the CL register plus the carry flag from the effective address (addressed by the ESI register plus an offset of 1):

sbbb %cl, 1(%esi)

Integer subtract the 16-bit constant, -126, plus the carry flag from the AL register:

sbbw $-126, %al

Integer subtract the 32-bit constant, 12345678, plus the carry flag from the effective address (addressed by the EDI register plus an offset of 4):

sbbl $12345678, 4(%edi)