Intel 80C188XL Instruction Set Descriptions, Table C-4.Instruction Set Continued, C-13, Name

INSTRUCTION SET DESCRIPTIONS

Table C-4. Instruction Set (Continued)

Name	Description	Operation	Flags
			Affected
DIV	Divide:	When Source Operand is a Byte:	AF ?
	DIV src	(temp) ← (byte-src)	CF ?
	Performs an unsigned division of the	if	DF –
			IF –
		(temp) / (AX) > FFH
	accumulator (and its extension) by the
			OF ?
		then (type 0 interrupt is generated)
	source operand.
			PF ?
		(SP) ← (SP) – 2
	If the source operand is a byte, it is
		((SP) + 1:(SP)) ← FLAGS	SF ?
	divided into the two-byte dividend	(IF) ← 0	TF –
	assumed to be in registers AL and AH.	(TF) ← 0	ZF ?
	The byte quotient is returned in AL,	(SP) ← (SP) – 2
	and the byte remainder is returned in
		((SP) + 1:(SP)) ← (CS)
	AH.
		(CS) ← (2)
	If the source operand is a word, it is
		(SP) ← (SP) – 2
	divided into the two-word dividend in	((SP) + 1:(SP)) ← (IP)
	registers AX and DX. The word	(IP) ← (0)
	quotient is returned in AX, and the	else
	word remainder is returned in DX.	(AL) ← (temp) / (AX)
	If the quotient exceeds the capacity of	(AH) ← (temp) % (AX)
	its destination register (FFH for byte	When Source Operand is a Word:
	source, FFFFH for word source), as	(temp) ← (word-src)
	when division by zero is attempted, a
		if
	type 0 interrupt is generated, and the
		(temp) / (DX:AX) > FFFFH
	quotient and remainder are undefined.
		then (type 0 interrupt is generated)
	Nonintegral quotients are truncated to
		(SP) ← (SP) – 2
	integers.
		((SP) + 1:(SP)) ← FLAGS
	Instruction Operands:
		(IF) ← 0
	DIV reg	(TF) ← 0
	DIV mem	(SP) ← (SP) – 2
		((SP) + 1:(SP)) ← (CS)
		(CS) ← (2)
		(SP) ← (SP) – 2
		((SP) + 1:(SP)) ← (IP)
		(IP) ← (0)
		else
		(AX) ← (temp) / (DX:AX)
		(DX) ← (temp) % (DX:AX)

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-13