Intel 80C186XL, 80C188XL Instruction Set Descriptions, Table C-4.Instruction Set Continued, C-44

INSTRUCTION SET DESCRIPTIONS

Table C-4. Instruction Set (Continued)

Name	Description	Operation	Flags
			Affected
STI	Set Interrupt-enable Flag:	(IF) ← 1	AF –
	STI		CF –
			DF –
	Sets IF to 1, enabling processor
			IF ¸
	recognition of maskable interrupt		OF –
	requests appearing on the INTR line.
			PF –
	Note however, that a pending interrupt
			SF –
	will not actually be recognized until the
			TF –
	instruction following STI has executed.
			ZF –
	Instruction Operands:
	none
STOS	Store (Byte or Word) String:	When Source Operand is a Byte:	AF –
	STOS dest-string	(DEST) ← (AL)	CF –
			DF –
	Transfers a byte or word from register	if
			IF –
		(DF) = 0
	AL or AX to the string element
			OF –
		then
	addressed by DI and updates DI to
			PF –
		(DI) ← (DI) + DELTA
	point to the next location in the string.
			SF –
		else
	As a repeated operation.
			TF –
		(DI) ← (DI) – DELTA
	Instruction Operands:
			ZF –
		When Source Operand is a Word:
	STOS dest-string
		(DEST) ← (AX)
	STOS (repeat) dest-string
		if
		(DF) = 0
		then
		(DI) ← (DI) + DELTA
		else
		(DI) ← (DI) – DELTA

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-44