Intel 80C186XL, 80C188XL user manual Procedure Entry, Enter locals, levels, Escape

INSTRUCTION SET DESCRIPTIONS

Table C-4. Instruction Set (Continued)

Name	Description	Operation	Flags
			Affected
ENTER	Procedure Entry:	(SP) ← (SP) – 2	AF –
	ENTER locals, levels	((SP) + 1:(SP)) ← (BP)	CF –
		(FP) ← (SP)	DF –
	Executes the calling sequence for a
		if	IF –
	high-level language. It saves the
		level > 0	OF –
	current frame pointer in BP, copies the
		then	PF –
	frame pointers from procedures below
		repeat (level – 1) times	SF –
	the current call (to allow access to
		(BP) ← (BP) – 2	TF –
	local variables in these procedures)
		(SP) ← (SP) – 2	ZF –
	and allocates space on the stack for
		((SP) + 1:(SP)) ← (BP)
	the local variables of the current
		end repeat
	procedure invocation.
		(SP) ← (SP) – 2
	Instruction Operands:
		((SP) + 1:(SP)) ← (FP)
	ENTER locals, level	end if
		(BP) ← (FP)
		(SP) ← (SP) – (locals)
ESC	Escape:	if	AF –
	ESC	mod ≠ 11	CF –
		then	DF –
	Provides a mechanism by which other
		data bus ← (EA)	IF –
	processors (coprocessors) may
			OF –
	receive their instructions from the 8086
			PF –
	or 8088 instruction stream and make
			SF –
	use of the 8086 or 8088 addressing
			TF –
	modes. The CPU (8086 or 8088) does
			ZF –
	a no operation (NOP) for the ESC
	instruction other than to access a
	memory operand and place it on the
	bus.
	Instruction Operands:
	ESC immed, mem
	ESC immed, reg

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

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