8086 Instruction Set Ppt 141126060207 Conversion Gate01

8/18/2019 8086 Instruction Set Ppt 141126060207 Conversion Gate01

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Instruction set ofInstruction set of

8086 Microprocessor 8086 Microprocessor


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• The sequence of commands used to tell a microcomputer what todo is called a program,

• Each command in a program is called an instruction• A program written in machine language is referred to as machine

code

ADD AX, X

!"pcode# !Destination operand# !$ource operand #

$oftware$oftware


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InstructionsInstructions

%AE%& I'$T()*TI"' + *"MME'T

Address identifier Does not generate an machine code

• Ex. START: MOV AX, BX ; copy BX into AX

• There is one!to!one re"tionship #et$een sse%#"y n&

%chine "n'('e instr(ctions

• A co%pi"e& %chine co&e i%p"e%enttion o) pro'r%

$ritten in hi'h!"e*e" "n'('e res("ts in ine))icient co&e

+ More %chine "n'('e instr(ctions thn n sse%#"e& *ersion o) n

e(i*"ent hn&$ritten sse%#"y "n'('e pro'r%


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• Two -e .enefits of assem.l language

programming

/ It ta-es up less memor

/ It eecutes much faster


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ApplicationsApplications

• "ne of the most .eneficial uses ofassem.l language programming is

real1time applications2

(eal time means the tas- required . the

application must .e completed .efore an other

input to the program that will alter its operation can

occur

3or eample the de4ice ser4ice routine which

controls the operation of the flopp dis- dri4e is a

good eample that is usuall written in assem.l

language


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• Assem.l language not onl good for

controlling hardware de4ices .ut also

performing pure software operations

/ $earching through a large ta.le of data for a special

string of characters

/ *ode translation from A$*II to E*DI* / Ta.le sort routines

/ Mathematical routines

Assem.l language& perform real1time operations

5igh1le4el languages& used to write those parts

that are not time critical


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*on4erting Assem.l %anguage Instructions

to Machine *ode• An instruction can .e coded with to 6 .tes• te contains three -inds of information

/ "pcode field !6 .its# specifies the operation !add, su.tract, mo4e#

/ (egister Direction it !D .it# Tells the register operand in (E7field in .te is source or destination operand

& destination 0& source

1 Data $i9e it !: .it# $pecifies whether the operation will .e

performed on 81.it or 61.it data

0& 8 .its & 6 .its


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• te has three fields

/ Mode field !M"D#

/ (egister field !(E7# used to identif the register for the first operand

/ (egister;memor field !(;M field#


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Mnemonic Meaning 3ormat "peration 3lags affected

M"< Mo4e Mo4 D,$ !$# !D# 'one

Data Transfer Instructions - MOVData Transfer Instructions - MOV

Destination Source

Memory Accumulator

Accumulator Memory

Register Register

Register Memory

Memory Register

Register Immediate

Memory Immediate

Seg reg Reg 16

Seg reg Mem 16

Reg 16 Seg reg

Memory Seg reg

NO MOV

Me%ory

%%e&ite

Se'%ent Re'ister

Me%ory

Se'%ent Re'ister

Se'%ent Re'ister

EX: MOV A4, B4


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Data Transfer Instructions - X!"Data Transfer Instructions - X!"

Mnemonic Meaning 3ormat "peration 3lags affected

X*57 Echange X*57 D,$ !$# !D# 'one

Destination Source

Accumulator Reg 16

Memory Register

Register Register

Register Memory

#$am%le& X!" START '(X)

6O X789MEMs

SE9 RE9s


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Data Transfer Instructions * +#A, +DS, +#SMnemo

nicMeaning 3ormat "peration 3lags

affected

%EA %oadEffecti4eAddress

%EA (eg6,EA EA !(eg6# 'one

%D$ %oad(egister

And D$

%D$ (eg6,MEM !MEM# !(eg6#

!Mem=# !D$#

'one

%E$ %oad(egister

and E$

%E$ (eg6,MEM !MEM# !(eg6#

!Mem=# !E$#

'one

+#A SI DATA or. MOV SI Offset DATA


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T/e X+AT InstructionT/e X+AT Instruction

Mnemonic Meaning 3ormat "peration 3lags

X%AT Translate X%AT !!A%#=!X#=!D$#0# !A%# 'one

Example:

Assume (DS) = 0300H, (BX)=0100H, and (AL)=0DH

XLAT replaces conens o! AL "# conens o! memor# loca$on %$&

'A=(DS)0 (BX) (AL) = 03000H 0100H 0DH = 0310DH

T&us

(0310DH) (AL)


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Arit/metic Instructions& ADD, AD, IN, AAA, DAA

Mnemonic Meaning 3ormat "peration 3lags

affected

ADD Addition ADD D,$ !$#=!D# !D#

carr !*3#

A%%

AD* Add withcarr

AD* D,$ !$#=!D#=!*3# !D#

carr !*3#

A%%

I'* Increment .one

I'* D !D#= !D# A%% .ut *>

AAA A$*II ad?ustfor addition

AAA After addition AAA instruction isused to ma-e sure the result is the

correct unpac-ed *D

A3,*3

DAA Decimalad?ust foraddition

DAA Ad?ust A% for decimal@ac-ed *D

A%%


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Eamples&

E2 ADD AX,

AD* AX,

E2 I'* X

I'* :"(D @T( XB

E2C A$*II *"DE 01 C01Ch

ADD *%,D% + *%BCA$*II 3"(

+ D%BCFA$*II 3"( F

+ (E$)%T*%B6G

M"< A%,*% +Mo4e the ascii result into A% sinceAAA ad?ust onl A%B

AAA +A%B0G, unpac-ed *D for G2


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Arit/metic Instructions * S0(, S((, D#, AAS, DAS, N#"

Mnemonic Meaning 3ormat "peration 3lagsaffected

$) $u.tract $) D,$ !D# 1 !$# !D#

orrow !*3#

All

$ $u.tractwith

.orrow

$ D,$ !D# 1 !$# 1 !*3# !D#

All

DE* Decrement. one

DE* D !D# 1 !D# All .ut *3

'E7 'egate 'E7 D All

DA$ Decimal

ad?ust forsu.traction

DA$ *on4ert the result in A% to

pac-ed decimal format

All

AA$ A$*IIad?ust for

su.traction

AA$ !A%# difference

!A5# dec . if .orrow

*>,A*


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Multiplication and Di4ision


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Multi%licationM0+ or IM0+.

Multi%licand O%erandMulti%lier.

Result

(yte(yte A+ Register or memory AX

2ord2ord AX Register or memory DX &AX

D3ordD3ord #AX Register or memory #AX DX

Di4ision

DIV or IDIV.

Di4idend O%erand

Di4isor.

5uotient& Remainder

2ord(yte AX Register or Memory A+ & A!

D3ord2ord DX&AX Register or Memory AX & DX

53ordD3ord #DX& #AX Register or Memory #AX & #DX



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Multiplication and Di4ision Eamples

#$1& Assume &a eac& $nsruc$on sars !rom &ese alues:

AL = *+H, BL = 3+H, AH = 0H

1 -.L BL / AL BL = *+H 3+H = 1B*H / AX = 1B*H

2 -.L BL / AL BL = 24S AL BL = 24S (*+H) 3+H = 5BH 3+H = 155H/ 24s comp / E6*H / AX

7 D8 BL / = = 02 (*+9023+=1B) /

D8 BL / = =

1B H

H

3+

00*+

02

A8 A4

BL

AX

BL AX

H

H

3+00*+

1B 02

A8 A4


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#$7& A+ 8 9:!, (+ 8 ;1!, A! 8 1 -.L BL / AL BL = ;3H 1H = *A3H / AX = *A3H

2 -.L BL / AL BL = 24S AL 24S BL = 24S (;3H) 24S(1H) =

0DH 6;H = 0+A3H / AX

3D8 BL / = = = 2/ (00;3 < 26;=1+H) BL

AX

)1(=2

300

H S

H F

FH

H F

6

300

AH AL

1 52

R 5

NEG NEG

POS = 2s ?E8

AH AL

1 ?E

D8 BL / = = 01/(;3911=62) / BL AX

H H F

1300

AH AL

62 01

R @


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#$:& AX8 9

DX AX

013 B555

2 -.L BX = 24S(;000H) 24S(01+H) = 1000 6;EB =

DX AX

5/?E B555

3 D8 BL = = B6DH / -ore &an ;;H / D$$de Error H

H F

1+000

D8 BL / = = >3H ? 5; / D$$de Error H

H F S

1+

)000(=2

H

H

1+

1000


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#$>& AX8 17=

1 D8 BL / = = = = = BL

AX

H

H

0

12+0

NEG

POS

sNEG

POS

=2 )0(=2

12+0

H s

H

H

H

50

12+0

> 28 258125!255 >58 BL

AX

H

H

0

12+0 R @58 258 A8 A4


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Mnemonic Meaning 9ormat O%eration 9lags Affected

AND

OR

XOR

NOT

+ogical AND

+ogical Inclusi4eOR

+ogical #$clusi4eOR

+O"IA+ NOT

AND D,S

OR D,S

XOR D,S

NOT D

S. ? D. H D.

S.@D. H D.

S. D.HD.

D. H D.

O9, S9, B9, C9,

9A9 undefined

O9, S9, B9, C9,9

A9 undefinedO9, S9, B9, C9,

9A9 undefined

None

C

%ogical Instructions

Destination Source

RegisterRegister

MemoryRegister

Memory

Accumulator

RegisterMemory

RegisterImmediate

Immediate

Immediate

DestinationRegister

Memory


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%"7I*A% Instructions

7 A@D

< .ses an# address$n mode excep memor#9o9memor# andsemen re$sers

< Espec$all# used $n clear$n cera$n "$s (mas$n)

xxxx xxxx AND 0000 1111 = 0000 xxxx

(clear &e !$rs !our "$s)

< Examples: A@D BL, 0;H

A@D AL, C3+H

7 F

< .sed $n se$n cera$n "$sxxxx xxxx OR 0000 1111 = xxxx 1111

(Se &e upper !our "$s)


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7 XF < .sed $n ner$n "$s

xxxx xxxx XF 0000 1111 = xxxxx4x4x4x4

-#$am%le& >lear "$s 0 and 1, se "$s 6 and 5, $ner "$ + o!re$ser >L:

A@D >L, ;>H G 1111 1100B

F >L, 0>0H G 1100 0000B

XF >L, 020H G 0010 0000B


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$hift and (otate Instructions

$5(;$A%& shift logical left;shiftarithmetic left

$5(& shift logical right

$A(& shift arithmetic right ("%& rotate left ("(& rotate right (*%& rotate left through carr

(*(& rotate right through carr


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4o'ic" *s Arith%etic Shi)ts

• A "o'ic" shi)t )i""s the ne$"y crete& #it position $ith Dero:

7 An ar$&me$c s&$! !$lls &e ne%l# creaed "$

pos$$on %$& a cop# o! &e num"er4s s$n "$:


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Allowed operands

Destination ount

Register

Register

Memory Memory

1

+

1

+


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$5% Instruction

• The S84


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3ast Multiplication

mov dl,5

shl dl,1

$hifting left .it multiplies a num.er .

mov dl,5

shl dl,2 ; DL = 20

$hifting left n .its multiplies the operand .

n

?or ex%p"e, 22 > 25


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Ex.

; M("tip"y AX #y 15S84 AX, 1

MOV BX, AX

MOV 74,2

S84 AX,74

A AX, BX


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$5( Instruction

• The S8R


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$A( Instruction

• $A( !shift arithmetic right# performs a rightarithmetic shift on the destination operand2

An rith%etic shi)t preser*es the n(%#ers si'n.

MOV DL,-80

SAR DL,1 ; DL = -40

SAR DL,2 ; DL = -10


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(otate Instructions(otate InstructionsMnem-onic

Meaning 9ormat O%eration 9lags Affected

RO+ Rotate+eft

RO+ D,ount Rotate t/e D. left y t/enumer of it %ositions eEualto ountH #ac/ it s/ifted outfrom t/e left most it goes acinto t/e rig/tmost it %ositionH

9O9 undefinedif count G 1

ROR Rotate

Rig/t

ROR D,ount Rotate t/e D. rig/t y t/e

numer of it %ositions eEualto ountH #ac/ it s/ifted outfrom t/e rig/tmost it goesac into t/e leftmost it%ositionH

9

O9 undefinedif count G 1

R+ Rotate

+eftt/roug/arry

R+ D,ount Same as RO+ e$ce%t carry is

attac/ed to D. for rotationH

9

O9 undefinedif count G 1

RR Rotaterig/t

t/roug/arry

RR D,ount Same as ROR e$ce%t carry isattac/ed to D. for rotationH

9O9 undefined

if count G 1


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("% Instruction

• ("% !rotate# shifts each .it to the left

• The highest .it is copied into .oth the *arr flagand into the lowest .it

• 'o .its are lost

MOV Al,11110000b

ROL Al,1 ; AL = 11100001b

MOV Dl,3Fh

ROL Dl,4 ; DL = F3h


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("( Instruction

• ("( !rotate right# shifts each .it to the right

• The lowest .it is copied into .oth the *arr flag andinto the highest .it

• 'o .its are lost

MOV AL,11110000b

ROR AL,1 ; AL = 01111000b

MOV DL,3Fh

ROR DL,4 ; DL = F3h


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(*% Instruction

• (*% !rotate carr left# shifts each .it to the left

• *opies the *arr flag to the least significant .it

• *opies the most significant .it to the *arr flag

CF

CLC ; CF = 0

MOV L,88H ; CF,L = 0 10001000b

RCL L,1 ; CF,L = 1 00010000b

RCL L,1 ; CF,L = 0 00100001b


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(*( Instruction

• (*( !rotate carr right# shifts each .it to the right

• *opies the *arr flag to the most significant .it

• *opies the least significant .it to the *arr flag

S!C ; CF = 1

MOV AH,10H ; CF,AH = 00010000 1

RCR AH,1 ; CF,AH = 10001000 0


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*ompare Instruction, *M@

Mnemonic

Meaning 3ormat "peration 3lagsAffected

7MG 7o%pre 7MG ,S !D# / !$# is (se& insettin' or resettin' the)"'s

7?, A?, O?,G?, S?, H?

!D# !$# + 30

!D# J !$# + 30, *30

!D# K !$# + 30, *3

Allowed "perands

Destination $ource

(egister(egister

(egisterMemor

Memor (egister

(egisterImmediate

Memor Immediate

Accumulator Immediate


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$tringL

• An arra of .tes or words located in

memor

• $upported $tring "perations

+ *op !mo4e, load#

+ $earch !scan#

+ $tore + *ompare


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$tring Instruction asics

• $ource D$&$I, Destination E$&DI

+ Io( %(st ens(re S n& ES re correct

+ Io( %(st ens(re S n& re o))sets into S n& ESrespecti*e"y

• irection ?"' Jp, 1 > o$n=

+ 74 ! ncre%ent &&resses


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$tring Instructions$tring Instructions

Instruction prefies

@refi )sed with Meaning

(E@

(E@E;(E@

(E@'E;(E@'

M"


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InstructionsInstructions

Mnemo1

'ic

meaning format "peration 3lags

effect1ed

MOVS Mo*e strin'

S:SES:

MOVSBKMOVSL


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Mnemo1

'ic

meaning format "peration

S7AS Scn strin'

AX + ES:

S7ASBK

S7ASL

Set )"'s s per


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ranch group of instructionsranch group of instructions

ranch instructions pro4ide lot of con4enience to theprogrammer to perform operations selecti4el, repetiti4eletc2

Brnch 'ro(p o) instr(ctions

7on&ition" N(%ps

Jncon&i!tion"

N(%p

tertioninstr(ctions

7A44instr(ctions

Ret(rninstr(ctions

$)(")TI'E N $)(")TI'E 5A'DI%I'7 I'$T()*TI"'$


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$)(")TI'E N $)(")TI'E 5A'DI%I'7 I'$T()*TI"'$

*all su.routine A

'et instruction

*all su.routine A'et instruction

Main program

$u.routine A

3irst Instruction

(eturn


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A s(#ro(tine is speci" se'%ent o) pro'r% tht cn #e c""e& )or

exec(tion )ro% ny point in pro'r%.

An sse%#"y "n'('e s(#ro(tine is "so re)erre& to s proce&(reP.

Lhene*er $e nee& the s(#ro(tine, sin'"e instr(ction is inserte& in tothe %in #o&y o) the pro'r% to c"" s(#ro(tine.

To #rnch s(#ro(tine the *"(e in the G or 7S n& G %(st #e

%o&i)ie&.

A)ter exec(tion, $e $nt to ret(rn the contro" to the instr(ction tht

i%%e&ite"y )o""o$s the one c""e& the s(#ro(tine i.e., the ori'in"*"(e o) G or 7S n& G %(st #e preser*e&.

Exec(tion o) the instr(ction c(ses the contents o) G to #e s*e& on

the stcQ.


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• Inter $egment

+ At starting *$ and I@ placed in a stac-2

+ 'ew 4alues are loaded in to *$ and I@ gi4en . theoperand2

+ After eecution original *$, I@ 4alues placed as it is2

3ar1procMemptrC

These two words !C .its# are loaded directl into I@ and

*$ with eecution at *A%% instruction2

3irst 6 I@

'et 6 *$


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(ET)('(ET)('

• E*ery s(#ro(tine %(st en& #y exec(tin' n instr(ction tht ret(rns contro" to

the %in pro'r%. This is the ret(rn


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%oop Instructions%oop Instructions

• These instr(ctions re (se& to repet set o) instr(ctions se*er"

ti%es.

• ?or%t: 4OOG Short!4#e"

• Opertion:


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Mne%onic %enin' )or%t Opertion

4OOG 4oop 4oop short!"#e" 5

*ontrol flow and O)M@ instructions*ontrol flow and O)M@ instructions


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)nconditional Oump)nconditional Oump

@art

OM@ AA)nconditional OM@

$-ipped part

@art C

AA XXXX

@art

'et instruction

*ontrol flow and O)M@ instructions*ontrol flow and O)M@ instructions

OM@ unconditional ?ump

OM@ "perand


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*onditional Oump instructions*onditional Oump instructions

*onditional Oump instructions in 8086 are ?ust .tes long2 1.teopcode followed . 1.te signed displacement !range of /8 to=G#2

*onditional Oump Instructions

Oumps .ased ona single flag

Oumps .ased onmore than one flag

*onditional Oump Instructions*onditional Oump Instructions


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*onditional Oump Instructions*onditional Oump Instructions

Mnemonic & Occ

Meaning & *onditional Oump

3ormat & Occ operand

"peration & If condition is true ?ump to the address specified . operand2

"therwise the net instruction is eecuted2

3lags affected & 'one

T>@E$T>@E$


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Mnemonic meaning condition

A A#o*e 7?>5 n& H?>5

B A#o*e or E(" 7?>5

B Be"o$ 7?>1

BE Be"o$ or E(" 7?>1 or H?>1

7 7rry 7?>1

7XH 7X re'ister is Hero 5

E E(" H?>1

9 9reter H?>5 n& S?>O?

9E 9reter or E(" S?>O?

4 4ess 1



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g

4E 4ess or E(" 1 or H)>1

6AE 6ot A#o*e nor E(" 7? > 1

6B 6ot Be"o$ 7? > 5

6BE 6ot Be"o$ nor E(" 7? > 5 n& H? > 5

67 6ot 7rry 7? > 5

6E 6ot E(" H? > 5

69 6ot 9reter


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64E 6ot 4ess nor E(" H? > 5 n& S? > O?

6O 6ot O*er)"o$ O? > 56G 6ot Grity G? > 5

6H 6ot Hero H? > 5

6S 6ot Si'n S? > 5

O O*er)"o$ O? > 1

G Grity G? > 1

GE Grity E*en G? > 1

GO Grity O&& G? > 5

S Si'n S? > 1

H Hero H? > 1

Oumps ased on a single flagOumps ased on a single flag


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Oumps ased on a single flagOumps ased on a single flag

O r8 +Oump if 9ero flag set to !Oump if result is 9ero#

O' r8 +Oump if 'ot ero ! flag 0 i2e2 result is non9ero#

O$ r8 +Oump if $ign flag set to !result is negati4e#

O'$ r8 +Oump if 'ot $ign !result is positi4e#

O* r8 +Oump if *arr flag set to

O'* r8 +Oump if 'o *arr

O@ r8 +Oump if @arit flag set to !@arit is e4en#

O'@ r8 +Oump if 'o @arit !@arit is odd#

O" r8 +Oump if "4erflow flag set to !result is wrong#

O'" r8 +Oump if 'o "4erflow !result is correct#

There is no ?ump

.ased on A* flag


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O r8 + OE !Oump if Equal# also means same2

O' r8 + O'E !Oump if 'ot Equal# also means same2

O* r8 +O !Oump if .elow# and O'AE !Oump if 'otA.o4e or Equal# also mean same2

O'* r8 +OAE !Oump if A.o4e or Equal# and O' !Oump if'ot A.o4e# also mean same2

O, O', O* and O'* used after arithmetic operation

OE, O'E, O, O'AE, OAE and O' are used after acompare operation2

O@ r8 + O@E !Oump if @arit E4en# also means same2

O'@ r8 + O@" !Oump if @arit "dd# also means same2

Eamples for OE or O instruction


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Ex. for forward jump


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Ex. for backward jump

BA7U: SJB BX, AX ; exec(te& i) H > 1

Sho("& #e

> 12

#ytes

: =

:

7MG S,

OE A*P

A 7X, X ;exec(te& i) H > 5


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Oumping .eond 18 to =GL

Requirement Then do this!

7MG S, 7MG S,

E SAME 6E 6EXT

Lht i)

120#ytes

A 7X, X MG SAME

: 6EXT: A 7X, X

: :

SAME: SJB BX, AX :

SAME: SJB BX, AX

Rn'e )or MG


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Terms used in comparison

A#o*e n& Be"o$ (se& )or co%prin' Jnsi'ne& nos.

9reter thn n& "ess thn (se& $ith si'ne& n(%#ers.

A"" nte" %icroprocessors (se this con*ention.

8 is #o*e /8 Jnsi'ne& co%prison ! Tr(e

8 is "ess thn /8 Si'ne& co%prison ! Tr(e

8 is ne'ti*e, /8 is positi*e

/8 is #e"o$ 8 Jnsi'ne& co%prison ! Tr(e

/8 is 'reter thn 8 Si'ne& co%prison ! Tr(e

Oump on multiple flagsOump on multiple flags


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Oump on multiple flagsOump on multiple flags

7on&ition" (%ps #se& on %ore thn one )"' re (se& )ter 7MG

1 OR H> 1 7y > 5 A6 H > 5 7MG BX, 7X

Be"o$ OR E(" S(re"y A#o*e BE BXWBE

BXWBE


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Oump on multiple flags contdOump on multiple flags contd..

6BE or

A

(%p i) 6ot 5 A6 H> 5 7y > 1 OR H > 1 7MG BX, 7X

S(re"y A#o*e Be"o$ OR E(" A BX#o*e

BX#o*e


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0-

Oump on multiple flags contdOump on multiple flags contd.

4E or

69

(%p i) 4ess thn OR E("

(%p i) 6ot 9reter thn

Jump if o Jump if

S > 1 A6 V > 5

1 OR H > 1

S > 5 A6 V > 5

5 A6 H > 5

Oump on multiple flags contd2Oump on multiple flags contd2


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0

Oump on multiple flags contd2Oump on multiple flags contd2

64E or

9

(%p i) 6ot 1=

5 1


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0/

Oump on multiple flagsOump on multiple flags contd2contd2

4 or69E

(%p i) 4ess thn(%p i) 6ot 1

Lhen S > 1, res("t cnnot #e 5

S > 5 A6 V > 5


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00

Oump on multiple flagsOump on multiple flags contd2contd2

64 or9E

(%p i) 6ot 4ess thn(%p i) 9reter thn OR E("

Jump if o Jump if

S > 5 A6 V > 5

1 A6 V > 5


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0

'ear Oump'ear Oump

6er (%p

irect (%p


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$hort Oump$ o t Ou p

2 #yte


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5

$hort Oump contd2p

S8ORT Asse%#"er irecti*e

Asse%#"er 'enertes on"y 2 #yte Short (%p co&e )or )or$r& N(%p, i) theS8ORT sse%#"er &irecti*e is (se&.

MG $5"(T SAMEGro'r%%er sho("& ens(re tht the(%p &istnce is >120 #ytes

:

:

SAME: MOV 7X, X

%ong Oump%ong Oump


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1

%ong Oump%ong Oump

3!#yte


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2

%ong Oump contd2%ong Oump contd2

t cn co*er entire /-U #ytes o) 7o&e se'%ent

4on' (%p cnhn&"e it s N(%p

(nt(% is>320/

BUL > 7S:55558

7S:5558 MG BUL

:

:

7S:????8


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%ong Oump or $hort OumpL%ong Oump or $hort OumpL


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-

g p pg p p

7n #e trete&s s%""

??E58. Too

*ery "on'

#cQ$r& N(%p

BUL> 7S:55158 :

:MG BUL

7S:???58

7S:????8

Intra segment indirect OumpIntra segment indirect Oump


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g pg p

6er n&irect (%p is (nco%%on.nstr(ction "en'th: 2 or %ore #ytes

Rn'e: co%p"ete se'%ent

Ex.1: MG X) X > 123-8, #rnches to 7S:123-8

123-8 is not si'ne& re"ti*e &isp"ce%ent

Ex. 2: MG $or&ptr 25558YBXZ

BX 123-8 S:323-8 /08 Brnches to

S:323/8 AB228 7S:/08

3ar Oump3ar Oump


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/

3ar Oump3ar Oump

?r (%p

irect (%p


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0

g pg p

Also called 3ar Direct Oump

It is the common inter segment ?ump scheme

It is a F .te instruction

.te opcode !EA5#

.te offset 4alue .te segment 4alue

E2 OM@ 3ar ptr %"*

Inter segment Indirect OumpInter segment Indirect Oump


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Inter segment Indirect Oumpte seg e t d ect Ou p

Instruction length depends on the wa ?ump location is

specifiedIt can .e a minimum of .tes

Ex. MG LOR GTR 25558YBXZ

Inter segment Indirect OumpInter segment Indirect Oump


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A"so c""e& ?r n&irect (%pt is not co%%on"y (se&

nstr(ction "en'th is %ini%(% o) 2 #ytes.

t &epen&s on the $y N(%p "oction is speci)ie&

Ex. MG LOR GTR 25558YBXZ

BX 123-8 Brnches to

AB78:/08

S:323-8 /08 t is -!#yte instr(ctionS:323/8 AB78

Machine control instructionsMachine control instructions


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5

Machine control instructionsMachine control instructions

5%T instr(ction + 8A4T processin'

the 84T instr(ction $i"" c(se the 5/ to stop )etchin' n& exec(tin'instr(ctions. The 5/ $i"" enter h"t stte. The on"y $y to 'et the processoro(t o) the h"t stte re $ith n interr(pt si'n" on the 6TR pin or n interr(ptsi'n" on 6M pin or reset si'n" on the RESET inp(t.

'"@ instr(ction

this instr(ction si%p"y tQes (p three c"ocQ cyc"es n& &oes no

processin'. A)ter this, it $i"" exec(te the next instr(ction. This instr(ction isnor%""y (se& to pro*i&e &e"ys in #et$een instr(ctions.

E$* instr(ction

$hene*er this instr(ction exec(tes, the %icroprocessor &oes 6OG orccess &t )ro% %e%ory )or coprocessor. This instr(ction psses thein)or%tion to 50 %th processor. Six #its o) ES7 instr(ction pro*i&e theopco&e to coprocessor.

$hen 5/ )etches instr(ction #ytes, co!processor "so picQs (p these#ytes n& p(ts in its (e(e. The co!processor $i"" tret nor%" 5/instr(ctions s 6OG. ?"otin' point instr(ctions re exec(te& #y 50 n&&(rin' this 5/ $i"" #e in LAT.

Machine control instructionsMachine control instructions contdcontd


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%"*P instr(ction

this is pre)ix to n instr(ction. This pre)ix %Qes s(re tht &(rin'exec(tion o) the instr(ction, contro" o) syste% #(s is not tQen #y other

%icroprocessor.in %("tiprocessor syste%s, in&i*i&(" %icroprocessors re connecte&

to'ether #y syste% #(s. This is to shre the co%%on reso(rces. Echprocessor $i"" tQe contro" o) this #(s on"y $hen it nee&s to (se co%%onreso(rce.

the "ocQ pre)ix $i"" ens(re tht in the %i&&"e o) n instr(ction, syste%#(s is not tQen #y other processors. This is chie*e& #y hr&$re si'n"[4O7U *i"#"e on one o) the 7GJ pin. This si'n" $i"" #e %&e cti*e&(rin' this instr(ction n& it is (se& #y the #(s contro" "o'ic to pre*entothers )ro% tQin' the #(s.

once this instr(ction is co%p"ete&, "ocQ si'n" #eco%es incti*e n&%icroprocessors cn tQe the syste% #(s.

:AIT instr(ctionthis instr(ction tQes 5/ to n i&"e con&ition. The 7GJ $i"" not &o ny

processin' &(rin' this. t $i"" contin(e to #e in i&"e stte (nti" TEST pin o)5/ #eco%es "o$ or n interr(pt si'n" is recei*e& on 6TR or 6M. On*"i& interr(pt SR is exec(te& n& processor enters the i&"e stte 'in

8086 Instruction Set Ppt 141126060207 Conversion Gate01

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Transcript of 8086 Instruction Set Ppt 141126060207 Conversion Gate01