Computing Some Basics
What your mother never told you about computer programming.
Von Neumann Model
M EM ORY
M AR M DR
IN P U T
K e yb o a rd M ouse Scanner D is k
O UTPUT P R O C E S S IN G U N IT
ALU TEM P
M o n ito r P rin te r LED D is k
C O N T R O L U N IT
PC IR
Memory
2k x m array of stored bits Address unique (k-bit) identifier of location Contents m-bit value stored in location
0000 0001 0010 0011 0100 0101 0110 1101 1110 1111
00101101
10100010
Basic Operations: LOAD read a value from a memory location STORE write a value to a memory location
Instruction
The instruction is the fundamental unit of work. Specifies two things: opcode: operation to be performed operands: data/locations to be used for operation An instruction encoded is as a sequence of bits. (Just like data!) Often, but not always, instructions have a fixed length, such as 16 or 32 bits. Control unit interprets instruction: generates sequence of control signals to carry out operation. Operation is either executed completely, or not at all. A computers instructions and their formats is known as its Instruction Set Architecture (ISA).
Instruction Processing
Fetch instruction from memory D...