How to find 1's and 2's complement without using CMA operation in 8085 microprocessor?

[Atri Pal]

In this problem, the given number is located at 8000H location. After finding the 1’s
complement and 2’s complement the result locations are 9000H and 9001H respectively.

address - 8000
data - FD

 

[FenTrac]

Subtract FD from FF to get the 1's compliment ( 00000010 ), and add 1 to the 1's complement to get the 2's complement ( 00000011 ).
Uses the add and subtract instructions, but not compare accumulator instruction ( CMA).

 

[KlausST]

Hi,

A simple internet search gives many results.
BTW: the problrm is not related to 8051 .. it's the same with all processors.

Hints: XOR, INV, COM, ADD, INC, SUB...even a lookup table is possible.

Klaus

 

[Atri Pal]

Subtract FD from FF to get the 1's compliment ( 00000010 ), and add 1 to the 1's complement to get the 2's complement ( 00000011 ).
Uses the add and subtract instructions, but not compare accumulator instruction ( CMA).

Thanks!! It worked!!