09. Instruction Set Architecture Context

The Instruction Set is the definition of the individual processes the computer can do. The context itself is the concept of a set of commands a computer can do. The variations are the particular commands and their application within a computer design. These are very simple processes that can be combined to produce very useful processing.

Each command is referred to by a set of bits in an op code. So using 4 bits for the op code we can have 16 different possible ops. Using 5 bits allows 32, 6 bits to 64, and 7 bits to 128 ops. It appears from Intel literature that the 80386 computer uses 8 bits for its op code. Each instruction is a hard-wired little program, inside the CPU, that causes the instruction to be done on the computer.

Dr. Jerome Heath

See also: The Animated Computer