80C186EB/80C188EB Microprocessor User's Manual - CEUNES

INSTRUCTION SET DESCRIPTIONSTable C-4. Instruction Set (Continued)Name Description OperationSBBNOTE:Subtract With Borrow:SBB dest, srcSubtracts the source from the destination,subtracts one if CF is set, andreturns the result to the destinationoperand. Both operands may be bytesor words. Both operands may besigned or unsigned binary numbers(see AAS and DAS)Instruction Operands:SBB reg, regSBB reg, memSBB mem, regSBB accum, immedSBB reg, immedSBB mem, immedif(CF) = 1then(dest) = (dest) – (src) – 1else(dest) ← (dest) – (src)The three symbols used in the Flags Affected column are defined as follows:– the contents of the flag remain unchanged after the instruction is executed? the contents of the flag is undefined after the instruction is executedüthe flag is updated after the instruction is executedFlagsAffectedAF üCF üDF –IF –OF üPF üSF üTF –ZF üC-41