1. Computer Fundamentals Northern College Diploma Philip Bird

2. Computer Fundamentals Philip Bird Processor Architecture Virtually every computer that has been built shares the same common layout. Von Neumann – programs and data both exist in the computers memory. A program written for one type of computer can be written for any computer.

3. Computer Fundamentals Philip Bird A Computer is a…..Binary/Electronic/Stored Program device Early History ABC Atanasoff/Berry 1942 Not working ENIAC Base 10 Mauchlay/Eckert 1946 UNIVAC Mauchlay/Eckert 1951 Manchester Mark1 Williams 1949 (Oct) Z3 Zuse 1941 Colossus Turing 1942 EDVAC Von Neumann 1952 EDSAC Wilkes 1949 (May) IAS Von Neumann 1952 LEO Wilkes 1951 Harvard Mark1 ASCC Aiken 1943 Mechanical Hard Wired Binary/Electronic/Memory BINAC Mauchlay/Eckert 1949 (Sept)

4. Computer Fundamentals Philip Bird Central Processing Unit Control Unit ALU Memory I/O Unit Directs the step by step working based on pulses sent from a clock The Arithmetic and Logic Unit perform the calculations using adder circuits. It also contains flags that monitor the result of those calculations. (CNZ) Memory is usually RAM or ROM made up of many individual cells each storing 1 byte. Both data and the programs are stored here. Handles communication with peripherals such as the keyboard. Busses are used to carry the data around the CPU in byte sized chunks.

5. Computer Fundamentals Philip Bird Central Processing Unit Memory Address Register Memory Data Register Program Counter Instruction Register Accumulator Flags +1 048 159 2610 3711

6. Computer Fundamentals Philip Bird Fetch Execute Cycle MAR MDR PC IR ACC +1 0 LOD 5 48 1 HLT 5 17 9 2610 3711 Repeat MAR=PC PC=PC+1 MDR=Memory[MAR] IR=MDR Execute IR Until halt 0 0 1 LOD 5 5 17 000

7. Computer Fundamentals Philip Bird Instructions Instructions are made up of 2 parts: Operation codeOperand 01000101Machine code ADD5Assembly Language Binary values are difficult to work. The assembler converts assembly language instructions into machine code. LOD 10 ADD 10 HLT Assembler 0001 1010 0100 1010 0000

8. Computer Fundamentals Philip Bird Instruction Set Op CodeOperandMeaning HLTHalt LOD5Load contents of address 5 into Accumulator STO5Store Accumulator in address 5 LDI5Load the number 5 into the Accumulator ADD5Add the contents of address 5 to the Accumulator SUB5Subtract the contents of address 5 from the Accumulator ADI5Add 5 to the Accumulator SBI5Subtract 5 from the Accumulator INCIncrease the Accumulator by 1 DECDecrease the Accumulator by 1 JMZ5Jump to address 5 if Accumulator is zero JNZ5Jump to address 5 if Accumulator is not zero JMN5Jump to address 5 if Accumulator is minus JMP5Jump to address 5 JCS5Jump to address 5 if Carry is set to 1 JCC5Jump to address 5 if Carry is set (clear) to 0

9. Computer Fundamentals Philip Bird Summary What is the Von Neumann architecture? What is the Fetch/Execute cycle? Use SCAry to try the example assembly programs.