80C186EC/80C188EC Microprocessor User's Manual

INSTRUCTION SET DESCRIPTIONS
Table C-4. Instruction Set (Continued)
Name Description Operation
Flags
Affected
STI
STOS
NOTE:
Set Interrupt-enable Flag:
STI
Sets IF to 1, enabling processor
recognition of maskable interrupt
requests appearing on the INTR line.
Note however, that a pending interrupt
will not actually be recognized until the
instruction following STI has executed.
Instruction Operands:
none
Store (Byte or Word) String:
STOS dest-string
Transfers a byte or word from register
AL or AX to the string element
addressed by DI and updates DI to
point to the next location in the string.
As a repeated operation.
Instruction Operands:
STOS dest-string
STOS (repeat) dest-string
(IF) ← 1 AF –
CF –
DF –
IF ü
OF –
PF –
SF –
TF –
ZF –
When Source Operand is a Byte:
(DEST) ← (AL)
if
(DF) = 0
then
(DI) ← (DI) + DELTA
else
(DI) ← (DI) – DELTA
When Source Operand is a Word:
(DEST) ← (AX)
if
(DF) = 0
then
(DI) ← (DI) + DELTA
else
(DI) ← (DI) – DELTA
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
üthe flag is updated after the instruction is executed
AF –
CF –
DF –
IF –
OF –
PF –
SF –
TF –
ZF –
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