Intel 80C188XL, 80C186XL user manual Convert Word to Doubleword, Decimal Adjust for Addition

		INSTRUCTION SET DESCRIPTIONS
	Table C-4. Instruction Set (Continued)
Name	Description	Operation	Flags
			Affected
CWD	Convert Word to Doubleword:	if	AF –
	CWD	(AX) < 8000H	CF –
		then	DF –
	Extends the sign of the word in register
		(DX) ← 0	IF –
	AX throughout register DX. Use to
		else	OF –
	produce a double-length (doubleword)
		(DX) ← FFFFH	PF –
	dividend from a word prior to
			SF –
	performing word division.
			TF –
	Instruction Operands:
			ZF –
	none
DAA	Decimal Adjust for Addition:	if	AF
	DAA	((AL) and 0FH) > 9 or (AF) = 1	CF
		then	DF –
	Corrects the result of previously
		(AL) ← (AL) + 6	IF –
	adding two valid packed decimal
		(AF) ← 1	OF ?
	operands (the destination operand
		if	PF
	must have been register AL). Changes
		(AL) > 9FH or (CF) = 1	SF
	the content of AL to a pair of valid
		then	TF –
	packed decimal digits.
		(AL) ← (AL) + 60H	ZF
	Instruction Operands:
		(CF) ← 1
	none
DAS	Decimal Adjust for Subtraction:	if	AF
	DAS	((AL) and 0FH) > 9 or (AF) = 1	CF
		then	DF –
	Corrects the result of a previous
		(AL) ← (AL) – 6	IF –
	subtraction of two valid packed
		(AF) ← 1	OF ?
	decimal operands (the destination
		if	PF
	operand must have been specified as
		(AL) > 9FH or (CF) = 1	SF
	register AL). Changes the content of
		then	TF –
	AL to a pair of valid packed decimal
		(AL) ← (AL) – 60H	ZF ¸
	digits.	(CF) ← 1
	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-11