INSTRUCTION SET DESCRIPTIONS

 

Table C-4. Instruction Set (Continued)

 

 

 

 

 

Name

Description

Operation

Flags

Affected

 

 

 

 

 

 

 

JO

Jump on Overflow:

if

AF –

 

JO disp8

(OF) = 1

CF –

 

then

DF –

 

Transfers control to the target location

 

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

IF –

 

if the tested condition (OF = 1) is true.

 

 

OF –

 

Instruction Operands:

 

 

 

PF –

 

JO short-label

 

SF –

 

 

 

TF –

 

 

 

ZF –

 

 

 

 

JP

Jump on Parity:

if

AF –

JPE

Jump on Parity Equal:

(PF) = 1

CF –

 

JP disp8

then

DF –

 

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

IF –

 

JPE disp8

 

 

OF –

 

Transfers control to the target location

 

 

 

PF –

 

if the tested condition (PF = 1) is true.

 

 

 

SF –

 

Instruction Format:

 

 

 

TF –

 

JP short-label

 

ZF –

 

JPE short-label

 

 

 

 

 

 

JS

Jump on Sign:

if

AF –

 

JS disp8

(SF) = 1

CF –

 

then

DF –

 

Transfers control to the target location

 

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

IF –

 

if the tested condition (SF = 1) is true.

 

 

OF –

 

Instruction Format:

 

 

 

PF –

 

JS short-label

 

SF –

 

 

 

TF –

 

 

 

ZF –

 

 

 

 

LAHF

Load Register AH From Flags:

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

AF –

 

LAHF

 

CF –

 

 

DF –

 

Copies SF, ZF, AF, PF and CF (the

 

 

 

IF –

 

8080/8085 flags) into bits 7, 6, 4, 2 and

 

 

 

OF –

 

0, respectively, of register AH. The

 

 

 

PF –

 

content of bits 5, 3, and 1 are

 

 

 

SF –

 

undefined. LAHF is provided primarily

 

 

 

TF –

 

for converting 8080/8085 assembly

 

 

 

ZF –

 

language programs to run on an 8086

 

 

 

 

 

or 8088.

 

 

 

Instruction Operands:

 

 

 

none

 

 

 

 

 

 

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-25

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Intel 80C188XL Name Description Operation Flags Affected Jump on Overflow, Jump on Parity Equal, Instruction Format