Semester: BE Computer Sem-5
Question: 8085 Programming Model
Answer :
Registers :-
the 8085 has 6 general purpose registers to store 8 bit data.
There are B, C, D, E, H & L.
They can be used as a pair for 16 bit storage like BC pair, DE pair & HL pair. Using instructions programmer can move data from on registers to other.
Accumulator :-
It is an 8 bit special register. It also known as A register. It is used in performing Arithmetic and logical operations.
Flags :-
Sign flag (S)
Zero flag (Z)
Auxiliary carry flag (AC)
Parity flag (P)
Carry flag (CY)
Program Counter :-
It is 16 bit register used to store the address of program.
The main function of PC is to sequence the execution of instructions.
Stack Pointer :-
It is also 16 bit register. It is used to store the stack memory address.
Internal register (W & Z) :-
These are 8 bit register which are used for internal temporary storage of data. It is only used by ALU and users are not permitted to use it.