Computer Views Computer Architecture CS 215 Some terms K kilo M mega G giga 210 1 024 220 1 048 576 230 1 073 741 824 T tera 240 Viewpoints User Programmer Architect Logic Designer User s View Often called end user Does not see implementation only end results Programmer s View Functional behavior of a computer as viewed by a programmer Instruction Set Architecture ISA Functional units Data type sizes operations etc Instruction Classes Data movement Arithmetic Logic Control flow More terms Machine state Contents of all registers and machine memory Procedure calls Used to implement functions Machine interrupts Unexpected interruptions to normal execution Exceptions Internal problems with normal execution Architect s View Structural relationships that are not visible to the programmer Driven by performance needs csot constraints Interfaces clock frequency memory etc Logic Designer s View Works in both Boolean logic and implementation Concerned with Design correctness Constraints Ex Fan in and Fan out Uses various design and analysis tools Von Neumann Model Input Unit Memory Unit Input Unit Arithemtic and Logical Unit ALU Control Unit Output Unit Provides instruction s and data to system Von Neumann Model Output Memory Unit Unit Input Unit Arithemtic and Logical Unit ALU Control Unit Output Unit Returns data from system Von Neumann Model Memory Memory Unit Input Unit Arithemtic and Logical Unit ALU Control Unit Output Unit Storage for instruction s and data Von Neumann Model ALU Memory Unit Input Unit Arithemtic and Logical Unit ALU Control Unit Output Unit Processes data Von Neumann Model Control Memory Unit Unit Input Unit Arithemtic and Logical Unit ALU Control Unit Output Unit Directs processin g Von Neumann Model CPU Memory Unit CPU Input Unit Arithemtic and Logical Unit ALU Control Unit Output Unit ALU and Control Unit combined System Bus Model Memory System Bus CPU ALU Registers Control Input Output I O Data Bus Address Bus Control Bus Streamlined version of von Nuemann model Data Bus Address Bus Control Bus Power Bus optional System Bus Model System Bus CPU ALU Registers Control Memory Input Output I O Data Bus Address Bus Control Bus Data Bus Carries the information being transmitted Sometimes implemented as data in and data out buses System Bus Model System Bus CPU ALU Registers Control Memory Input Output I O Data Bus Address Bus Control Bus Address Bus Identifies where the information is being sent Memory address identifies read write location System Bus Model System Bus CPU ALU Registers Control Memory Input Output I O Data Bus Address Bus Control Bus Control Bus Describes aspects of how the information is being sent in what manner Machine Levels User or Application Program Level High Level Language Level Assembly Language Machine Code Level Control Level Functional Unit Level Logic Gates Transistors Wires Each level represents an abstraction of the computer Levels are kept relatively independent from one another Can allow for upward compatibility User or Application Program Level User or Application Program Level High Level Language Level Assembly Language Machine Code Level Control Level Functional Unit Level Logic Gates Transistors Wires User interacts with computer High Level Language Level User or Application Program Level High Level Language Level Assembly Language Machine Code Level Control Level Functional Unit Level Logic Gates Transistors Wires Compiler maps data types and instructions to actual computer hardware Can be recompiled in different environments Source code compatibility Assembly Language Machine Code Level User or Application Program Level Language of the High Level Language Level Assembly Language Machine Code Level Control Level Functional Unit Level Logic Gates Transistors Wires computer Instruction sets Assembler substitutes instruction codes for mnemonics Different hardware can support same instruction set Control Level User or Application Program Level High Level Language Level Assembly Language Machine Code Level Control Level Functional Unit Level Logic Gates Transistors Wires Effects register transfers Control signals transfer data from register to register Hardwired Vs Microprogram control firmware microcontroller Functional Unit Level User or Application Program Level High Level Language Level Assembly Language Machine Code Level Control Level Functional Unit Level Logic Gates Transistors Wires Internal CPU registers ALU Computer s main memory Logic Gates Transistors Wires User or Application Program Level High Level Language Level Assembly Language Machine Code Level Control Level Functional Unit Level Logic Gates Transistors Wires The hardware More on this later Question User or Application Program Level High Level Language Level Assembly Language Machine Code Level Control Level Functional Unit Level Logic Gates Transistors Wires Which levels map to which views Machine Levels Floating point emulation Due to insufficient resources Floating point instructions are trapped Replaced with machine code to imitate floating point instructions Emulation Vs Math coprocessor Typical Computer System Input Keyboard Output Monitor Storage Floppy disk hard disk CD ROM etc Motherboard CPU RAM expansion slots bus etc