Intel 80C186EA User Manual page 349

INSTRUCTION SET DESCRIPTIONS
Name
ENTER Procedure Entry:
ENTER locals, levels
Executes the calling sequence for a
high-level language. It saves the
current frame pointer in BP, copies the
frame pointers from procedures below
the current call (to allow access to
local variables in these procedures)
and allocates space on the stack for
the local variables of the current
procedure invocation.
Instruction Operands:
ENTER locals, level
ESC Escape:
ESC
Provides a mechanism by which other
processors (coprocessors) may
receive their instructions from the 8086
or 8088 instruction stream and make
use of the 8086 or 8088 addressing
modes. The CPU (8086 or 8088) does
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
ü
the flag is updated after the instruction is executed
C-14
Table C-4. Instruction Set (Continued)
Description Operation
(SP) ← (SP) – 2
((SP) + 1:(SP)) ← (BP)
(FP) ← (SP)
if
level > 0
then
repeat (level – 1) times
(BP) ← (BP) – 2
(SP) ← (SP) – 2
((SP) + 1:(SP)) ← (BP)
end repeat
(SP) ← (SP) – 2
((SP) + 1:(SP)) ← (FP)
end if
(BP) ← (FP)
(SP) ← (SP) – (locals)
if
mod ≠ 11
then
data bus ← (EA)
Flags
Affected
AF –
CF –
DF –
IF –
OF –
PF –
SF –
TF –
ZF –
AF –
CF –
DF –
IF –
OF –
PF –
SF –
TF –
ZF –