Advanced Embedded Systems Interview Question:

Explain how is a program executed' bit by bit' or' byte by byte'?

Submitted by: Muhammad

EXAMPLE:
ADDRESS OPCODE PROGRAM
1 0000 ORG 0H
2 0000 7D25 MOV R5,#25H
3 0002 7F34 MOV R7,#34H
4 0004 2D ADD A, R5
5 0005 END

☛ A program is always executed byte by byte.
☛ Firstly,1st opcode 7D is fetched from location 0000 and then the value 25 is fetched from 0001 .
☛ 25 is then placed in the register R5 and program counter is incremented to point 0002.
☛ On execution of opcode 7F, value 34 is copied to register R7.
☛ Then addition of contents of R5 and accumulater takes place.
☛ Here all the opcodes are 8 bit forming a byte.
Submitted by: Muhammad