Mechatronic Systems Engineering 2202A/B Lecture Notes - Lecture 7: Opcode

• School: Western University
• Department: Mechatronic Systems Engineering
• Course: Mechatronic Systems Engineering 2202A/B
• Professor: Naish

Document Summary

Consider the addition of the numbers 3 and 4, placing the result in memory address 9. The operation will involve the accumulator (working register) because the accumulator. Each address is split into high and low bytes. Words like load, add, and store cannot be understood by the microprocessor. Everything must be given to the microprocessor in binary. Operations are therefore represented as an 8-bit binary code expressed in hex: 86 (load), 8b (add), and b7 (store) These numbers are called operation codes or (op codes) for short. The binary numbers presented to the microprocessor are called machine language. Instructions consist of op codes plus up to two more data bytes (numbers, addresses, etc. ) following each op code. There is no distinction between op codes and data bytes except the order of their presentation. The op code is decoded to determine how many of the following bytes are part of the instruction. Programming in machine language is next to impossible.