Page 386 - FUNDAMENTALS OF COMPUTER
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386 Fundamentals of Computers NPP
It will cause addition of contents of pro- Bggo R VWm R Ho$ H§$Q>|Q> H$m `moJ hmoJm VWm
3
2
cessor register R and R . The result is placed n[aUm_ R _| OmEJmŸ& a{OñQ>a Q´>m§g\$a b¢½doO _| Bgo
2
3
in the register R . In register transfer language 1
1
it can be stated as: {ZåZmZwgma Xem© gH$Vo h¢:
R R + R 3
2
1
The contents of R and R will remain un- `hm± na R d R _| H$moB© n[adV©Z Zht hmoJmŸ& {ZåZ
3
2
3
2
changed. Following table gives three address Vm{cH$m _| W«r ES´>og BÝñQ´>³eÝg VWm gå~pÝYV
instructions and the corresponding microo-
peration. A, B, C etc are supposed to be memory _mBH«$moAm°naoeZ Xem©E JE h¢Ÿ& `hm± na A,B,C Am{X _o_moar
addresses. ES´>og h¢:
Instruction Microoperation
ADD R , A, B R ← M[A] + M[B}
1
1
MUL R , C, D R ← M[C] * M[D]
1
1
R 1
DIV X, R , R 2 M[X] ← R 2
1
The instruction ADD X, A, B is not allowed {ZX}e: ADD X, A,B Zht McoJm Š`m|{H$ gmog© VWm
because both source and destination cannot be S>opñQ>ZoeZ XmoZm| _o_moar bmoHo$eZ Zht hmo gH$VoŸ& H$_ go H$_
memory locations. Atleast one register oper-
and is necessary. EH$ a{OñQ>a Am°na|S> Amdí`H$ h¡Ÿ&
2. Two Address Instructions 2. Xmo-ES´>og {ZX}e
This type of instruction has following for- Bg àH$ma Ho$ {ZX}e H$m \$m°_}Q> Bg àH$ma hmoVm h¡:
mat:
Instruction
Opcode Operand 1 Operand 2
Normally operand 1 is the destination. gm_mÝ`V: operand 1 S>opñQ>ZoeZ hmoVm h¡Ÿ& XmoZm|
Both the operands cannot be memory. If oper- Am°naoÝS> ‘o‘moar Zht hmo gH$Vo h¢& `{X operand 2 S>mQ>m h¡
and 2 is a data, then operand1 can be a register Vmo operand 1 a{OñQ>a `m _o_moar hmoJmŸ& {ZåZ CXmhaU
or memory. For example:
XoImo:
ADD R , R 2
1
It means add contents of registers R and Bggo VmËn`© h¡ {H$ R VWm R H$s g§»`m H$mo Omo‹S>mo
1
1
2
R . The result is placed in the register R . In VWm n[aUm_ R _| S>mcmoŸ& a{OñQ>a Q´>m§g\$a b¢½doO _| Bg
1
2
1
register transfer language this microoperation {ZX}e H$mo {ZåZmZwgma {cIm OmEJm:
can be stated as:
R R + R 2
1
1
Following table indicates different two op- {ZåZ Q>o~c {d{^Þ Xmo-Am°na|S> {ZX}e VWm g§~§{YV
erand instructions and the corresponding _mBH«$moAm°naoeZ H$mo Xem©Vr h¡:
microoperation:
