999 views
2 votes
2 votes

Is Displacement mode and base register mode both are same??

  • in register direct mode we access operand from register directly
  • in register indirect mode we access operand from visiting register + visiting inside register(here register is treated as effective address)
  • in the base register mode visit base register then according to given  offset inside base register visit there 
  • in direct address mode, we access operand from    the main memory directly
  • in indirect address mode, we have given the normal address after visit normal address we have given the effective address in the main memory

it means direct address mode and direct register address mode  both are the same

the only difference is in direct register address mode uses to register and direct address mode uses main memory to access the operands

same for indirect  register address mode and indirect address mode

if I am wrong please let me correct with giving the proper explanation.

1 Answer

Best answer
1 votes
1 votes

Is Displacement mode and base register mode both are same??

Yes, both ae same. 

Base-register addressing is a type of Displacement mode .

Displacement Mode =  Register direct Mode + Register indirect addressing mode 

example :  in Displacement addressing we calculate Effective Address as EA = A + (R)

like  Add R4, 100(R1)  means R4 <- R4 + M[100+R1]  //  here displacement is 100 . We add 100 with register R1 value and get the memory address that is M[100+R1] ,  then get that value store in memory address and add that value with R4 . And finally store that addition into R4 .


 Base-Register Addressing:The reference register contains a memory address, and the address field contains a displacement from that address. The register reference may be explicit or implicit.

MOV AL,[BX+7] // here BX is a base register and displacement is 7

// suppose the register BX contain 0103.The offset will be 0103+7=0110.  Content of the memory location 0110  will move to AL.

so it is same as displacement addressing mode.

edited by

Related questions

0 votes
0 votes
1 answer
1
lea asked Jun 12, 2023
290 views
0 votes
0 votes
1 answer
2
Aaryan_Sharma asked Dec 30, 2022
369 views
When we write MOV #1000 , it means we are writing the value 1000 into the accumulator. But when we write MOV 1000 here 1000 refers to address of what ? register or MM ? (...
2 votes
2 votes
1 answer
3
Subbu. asked Jul 14, 2022
495 views
Could you please explain How we can implement indirect addressing mode using Index addressing mode.. and vice versa..??