Instructions In Microprocessor
An instruction is a binary pattern designed inside the microprocessor to perform a specific function. In other words, it is actually a command to the microprocessor to perform a given task on specified data.
Each instruction has two parts: one is the task to be performed called the operation code (opcode) and the other is the data to be operated on called the operand (data).
Instruction And Word Size
1. One word or one byte Instruction
It includes the opcode and operand in the same byte.
2. Two word or two byte Instruction
First byte specifies the opcode and second byte specifies the operand.
MVI A, 05
3. Three word or three byte Instruction
The first byte specifies the opcode and the following two bytes specify the 16 bit address. The second byte is lower order and the other is higher order.