Intel 80C186XL, 80C188XL Return, RET optional-pop-value, Rotate Left, ROL dest, count

INSTRUCTION SET DESCRIPTIONS

Table C-4. Instruction Set (Continued)

Name	Description	Operation	Flags
			Affected
RET	Return:	(IP) ← ((SP) = 1:(SP))	AF –
	RET optional-pop-value	(SP) ← (SP) + 2	CF –
		if	DF –
	Transfers control from a procedure
		inter-segment	IF –
	back to the instruction following the
		then	OF –
	CALL that activated the procedure.
		(CS) ← ((SP) + 1:(SP))	PF –
	The assembler generates an intra-
		(SP) ← (SP) + 2	SF –
	segment RET if the programmer has
		if	TF –
	defined the procedure near, or an
		add immed8 to SP	ZF –
	intersegment RET if the procedure has
		then
	been defined as far. RET pops the
		(SP) ← (SP) + data
	word at the top of the stack (pointed to
	by register SP) into the instruction
	pointer and increments SP by two. If
	RET is intersegment, the word at the
	new top of stack is popped into the CS
	register, and SP is again incremented
	by two. If an optional pop value has
	been specified, RET adds that value to
	SP.
	Instruction Operands:
	RET immed8
ROL	Rotate Left:	(temp) ← count	AF –
	ROL dest, count	do while (temp) ≠ 0	CF
		(CF) ← high-order bit of (dest)	DF –
	Rotates the destination byte or word
		(dest) ← (dest) × 2 + (CF)	IF –
	left by the number of bits specified in
		(temp) ← (temp) – 1	OF ¸
	the count operand.	if	PF –
	Instruction Operands:
		count = 1	SF –
	ROL reg, n	then	TF –
	ROL mem, n	if	ZF –
	ROL reg, CL	high-order bit of (dest) ≠ (CF)
	ROL mem CL	then
		(OF) ← 1
		else
		(OF) ← 0
		else
		(OF) undefined

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-38