Intel 80C188XL User Manual

Page 348

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C-25

INSTRUCTION SET DESCRIPTIONS

JO

Jump on Overflow:

JO

disp8

Transfers control to the target location
if the tested condition (OF = 1) is true.

Instruction Operands:

JO short-label

if

(OF) = 1

then

(IP)

(IP) + disp8 (sign-ext to 16 bits)

AF –
CF –
DF –
IF –
OF –
PF –
SF –
TF –
ZF –

JP
JPE

Jump on Parity:
Jump on Parity Equal:

JP disp8
JPE

disp8

Transfers control to the target location
if the tested condition (PF = 1) is true.

Instruction Format:

JP short-label
JPE

short-label

if

(PF) = 1

then

(IP)

(IP) + disp8 (sign-ext to 16 bits)

AF –
CF –
DF –
IF –
OF –
PF –
SF –
TF –
ZF –

JS

Jump on Sign:

JS

disp8

Transfers control to the target location
if the tested condition (SF = 1) is true.

Instruction Format:

JS short-label

if

(SF) = 1

then

(IP)

(IP) + disp8 (sign-ext to 16 bits)

AF –
CF –
DF –
IF –
OF –
PF –
SF –
TF –
ZF –

LAHF

Load Register AH From Flags:

LAHF

Copies SF, ZF, AF, PF and CF (the
8080/8085 flags) into bits 7, 6, 4, 2 and
0, respectively, of register AH. The
content of bits 5, 3, and 1 are
undefined. LAHF is provided primarily
for converting 8080/8085 assembly
language programs to run on an 8086
or 8088.

Instruction Operands:

none

(AH)

(SF):(ZF):X:(AF):X:(PF):X:(CF)

AF –
CF –
DF –
IF –
OF –
PF –
SF –
TF –
ZF –

Table C-4. Instruction Set (Continued)

Name

Description

Operation

Flags

Affected

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

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