16 bit Assembly
Home Site Map Instruction Index
SBB - Subtract with Borrow Instruction
The SBB instruction Subtracts the second operand from the first operand and leaves the result in the first.
The carry flag is set to indicate if there is a borrow from the previous subtraction.
This command has 3 parts, Instruction, then either a Register or memory address, followed by a Register, an immediate value or a memory address.
| Assembly Sample | Description | 16 bit Machine Code |
|---|---|---|
| SBB AL, 0x03 | ; 8 bit immediate from AL | 1C 03 |
| SBB AX, 0x0303 | ; 16 bit immediate from AX | 1D 03 03 |
| SBB CL, 0x03 | ; 8 bit immediate from an 8 bit Register | 80 D9 03 |
| SBB CX, 0x03 | ; 8 bit immediate from 16 bit Register | 83 D9 03 |
| SBB CX, 0x0303 | ; 16 bit immediate from a Register | 81 D9 03 03 |
| SBB CL, AL | ; 8 bit Register from 8 bit Register | 1A C8 |
| SBB CX, AX | ; 16 bit Register from 16 bit Register | 1B C8 |
| SBB [BX], 0x03 | ; 8 bit immediate from memory address | 83 1F 03 |
| SBB [BX], 0x0303 | ; 16 bit immediate from memory address | 81 1F 03 03 |
| SBB [BX+2], 0x0033 | ; 16 bit Immediate from memory address | 81 5F 02 23 00 |
| SBB AX, [BX] | ; Memory address from 16 bit Register | 1B 07 |
| SBB [BX], AX | ; 16 bit Register from memory address | 19 07 |
| SBB AX, [BX+2] | ; 16 bit Register from memory address | 1B 47 02 |
| SBB [BX+2], AX | ; 16 bit Register from memory address | 19 47 02 |
Last Update 14/02/2023