Machine Instruction Formats
Machine Instruction Formats
There are several instruction formats (templates that indicates the role of each byte of an instruction) for S08 instructions. I will start with a very basic one. Its official name is the Extended Addressing format. Each extended addressing instruction consists of a one-byte operation code (opcode, for short) followed by a two-byte address called the instruction operand. It is a good idea to think of the two-byte address portion as a pointer constant. It is a pointer in that its 16-bit value is going to be used to identify a memory location involved in the instruction. It …