1. Computer Operation

2. Binary Codes CPU operates in binary codes Representation of values in binary codes Instructions to CPU in binary codes Addresses in binary codes

3. Computer Architecture Input unit Main Memory ALU Control unit Output unit Backing Store Control signal Data/ Instructions

4. CPU Silicon chip Millions of electronic components Very large scale Integrated Circuit Speed – MHz, GHz Pentium (Intel) PowerPC (Apple/Mac) M68000 (Motorola)

8. Computer Organization

10. Speeding up processing - Pipelining

11. Speed of CPU

13. CPU and Memory The CPU fetches instructions from memory, fetches(load) data from memory, and store data back in memory after calculation. Memory consists of a large number of locations each having a unique address Each location consists of 8 bits(1 byte) The number of bits representing the addresses determines the address space (e.g. 10 bit address  1024 locations (=1K) 20 bits  1 M(?), 32 bits  4 G (?))

14. Main Memory (RAM) Main Memory 10-bit Address (decimal) 0000000000 0 0000000001 1 0000000010 2 0000000011 3 1111111111 1024........................

15. Machine Instructions CPU can only understand and execute machine instructions that is designed when the chip is manufactured We call the language that CPU understands ‘ Machine Language ’ All ‘ High-level language ’ programs must be translated to machine instructions before executing (e.g. Pascal  compiler  machine instructions) The whole set of machine instructions for a CPU is called Instruction Set Different CPUs have different machine instruction sets

16. For example For I:=1 to 10 do Sum:=sum+I Pascal statements Machine instructions 10101001 00110101 00011010 00101001 11110000 10010000 00111100 00101111 00100010  Translated to.. Pascal compiler  

17. Assembly language Machine language is difficult to design, debug and understand Use abbreviations(short forms) to replace machine instructions One machine instr. corresponds to one assembly instruction  assembly language e.g. 01001001 01101111  LDA sum

18. Components of control unit Program counter (PC) Instruction register (IR) Processor status word (PSW) Instruction Decoder

19. Components of ALU Accumulator Arithmetic and logic operations circuits Registers