Test by Bikram | Mock GATE | Test 3 | Question: 39

Question

The register $’V’$ contains the value $’500’$. The index register contains the value $’100’$.

The address field value of an indexed addressing mode instruction to make it same as a register indirect mode instruction is ___________.

Comments

Sir, why is  600 (500+100) wrong ?

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@harsh

please check my answer, hope it will be clear to you.

Answer 1

In indexed addressing mode
Effective address = address + contents of specified index register

In register indirect mode

Effective PC address = contents of register 'V'

Now , the address field value of an indexed addressing mode instruction to make it  same as a register indirect mode instruction , we need to do is :

contents of register ' V ' = address + contents of index register

address = contents of register ' V ' - contents of index register

= 500-100

= 400 

Comments

very well explained sir!!!