Intel 80C186XL, 80C188XL user manual Table C-4. Instruction Set

INSTRUCTION SET DESCRIPTIONS

Table C-4. Instruction Set

Name	Description	Operation	Flags
			Affected
AAA	ASCII Adjust for Addition:	if	AF
	AAA	((AL) and 0FH) > 9 or (AF) = 1	CF ¸
	Changes the contents of register AL to	then	DF –
		(AL) ← (AL) + 6	IF –
	a valid unpacked decimal number; the
		(AH) ← (AH) + 1	OF ?
	high-order half-byte is zeroed.
		(AF) ← 1	PF ?
	Instruction Operands:
		(CF) ← (AF)	SF ?
	none	(AL) ← (AL) and 0FH	TF –
			ZF ?
AAD	ASCII Adjust for Division:	(AL) ← (AH) × 0AH + (AL)	AF ?
	AAD	(AH) ← 0	CF ?
			DF –
	Modifies the numerator in AL before
			IF –
	dividing two valid unpacked decimal
			OF ?
	operands so that the quotient
			PF
	produced by the division will be a valid
			SF
	unpacked decimal number. AH must
			TF –
	be zero for the subsequent DIV to
			ZF ¸
	produce the correct result. The
	quotient is returned in AL, and the
	remainder is returned in AH; both high-
	order half-bytes are zeroed.
	Instruction Operands:
	none
AAM	ASCII Adjust for Multiply:	(AH) ← (AL) / 0AH	AF ?
	AAM	(AL) ← (AL) % 0AH	CF ?
			DF –
	Corrects the result of a previous multi-
			IF –
	plication of two valid unpacked
			OF ?
	decimal operands. A valid 2-digit
			PF
	unpacked decimal number is derived
	from the content of AH and AL and is		SF
	returned to AH and AL. The high-order		TF –
	half-bytes of the multiplied operands		ZF ¸
	must have been 0H for AAM to
	produce a correct result.
	Instruction Operands:
	none

NOTE: 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 executed

the flag is updated after the instruction is executed

C-4