Page 380 - FUNDAMENTALS OF COMPUTER

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380 Fundamentals of Computers NPP

It stands for "Complement Accumulator”. AWm©V² ""H$m§ßcr_|Q> EŠ`yå`ycoQ>a'' Bg_| H$moB© Am°na|S>
No operand is specified since it is a part of {ZYm©[aV Zht h¡ Š`m|{H$ `h Am°nH$moS> H$m hr EH$ {hñgm
opcode. Contents of Accumulator is to be oper-
ated up on. h¡& EŠ`yå`ycoQ>a a{OñQ>a Ho$ A§Xa H$s g§»`m EH$ go ~‹T>oJrŸ&
Similarly consider following 8086 Instruc- Bgr àH$ma go {ZåZ 8086 BÝñQ´>³eZ H$mo XoImo…
tion:
LAHF
It stands for "Load AH from Flag". It has no AWm©V² ''cmoS> AH \«$m°_ âcoJ'' Bg_| ^r H$moB©
operand. Low byte from flag is transferred into Am°na|S> \$sëS> Zht h¡& âcoJ a{OñQ>a H$s cmo ~mB©Q>
register AH.
{ZH$cH$a a{OñQ>a AH _| H$m°nr hmo OmVr h¡&
In stack-organised computer all computa- ñQ>oH$-Am°J}ZmBÁS> H$åß`yQ>g© _| JUZmË_H$ {ZX}e
tional instructions are zero operand instruc- eyÝ`- Am°na|S> (Am°na|S>-a{hV) hmoVo h¢ Ÿ& ñQ>oH$ Ho$ Xmo
tions. Two words from top of the stack are D$nar eãXm| (g§»`mAm|) H$mo Bpåßb{gQ> ê$n go {b¶m OmVm
taken implicitly. Thus ADD, MUL, DIV etc. in
stack-organised computers use implied ad- h¡& Bg àH$ma ñQ>oH$ Am°J}ZmBÁS> H$åß`yQ>a _| ADD,
dressing mode. All zero-Address Instruction MUL, DIV Am{X BåßcmB©S> ES´>oqgJ _moS> H$m Cn`moJ
use implied addressing mode. H$aVo h¢& g^r Oramo-ES´>og BÝñQ´>³eZ BåßbmBS> ES´>oqgJ

‘moS> H$m Cn¶moJ H$aVo h¢&
Instruction Opcode

Opcode datum

5.2.2 Immediate Addressing Mode 5.2.2 B_r{OEQ> ES´>oqgJ _moS>
The datum to be operated is in the instruc- {Og g§»`m na {H«$`m H$aZm hmoVr h¡ dh g§»`m {ZX}e
tion itself. Consider the following 8086 Instruc- _| hr {cIr OmVr h¡ Ÿ& O¡go {ZåZ 8086 Ho$ {ZX}e H$mo XoImo:
tion:

ADD AH, 46H
In this instruction the source operand is an CnamoŠV {ZX}e _| gmog© Am°naoÝS> EH$ 8-{~Q> S>oQ>‘
8-bit datum 46H. This is called Immediate op- 46H h¡Ÿ& Bgo hr B_r{OEQ> Am°na|S> H$hVo h¢Ÿ& Bg {ZX}e
erand. This datum is to be added with contents
of register AH and the results are placed in AH. _| `h g§»`m AH Ho$ A§Xa H$s g§»`m Ho$ gmW Ow‹S> OmVr
Thus, source operand has immediate address- h¡ d n[aUm_ AH _| Mcm OmVm h¡Ÿ& AV… gmog© Am°naoÝS>
ing mode. In microprocessor 8085 following ‘| B_r{OEQ> ES´>oqgJ _moS hmoVm >h¡Ÿ& _mBH«$moàmogoga 8085
instruction has Immediate addressing mode: _| ^r B‘r{OEQ> ES´>oqgJ ‘moS> h¡Ÿ& O¡go…
ADI 46H
The second operand is implicit and it re- Xygar g§»`m EŠ`yå`ycoQ>a Zm_H$ a{OñQ>a _| hmoVr
sides in Accumulator. The source operand is
46H, which is an 8- bit datum or immediate h¡Ÿ& gmog© Am°naoÝS> 46H h¡ Omo EH$ 8-{~Q> S>oQ>‘ ¶m
operand. Some examples are given for 8085 and B‘r{OEQ> Am°naoÝS> h¡& 8085 VWm 8086 Ho$ Hw$N>
8086: CXmhaU ZrMo {X`o JE h¢…