Survey of Program Compilation and

Execution

Bangor High School

Ali Shareef2/28/06

Main Components of a Computer

External Devices Processor Memory

Memory Temporary holding area where

instructions are stored while they are waiting to be executed.

Data and intermediate values are also stored in memory.

Memory is Volatile When the power is shut off, everything

in memory is lost

Processor

Executes Instruction Pentium 4 is a 32 bit processor

Processors can process a 32 digit “bit” number at a time.

Processor executes instructions one at a time, (technically).

Instructions are represented as binary numbers.

Processor

Registers Fast memory within the processor

where data is stored while an instruction is being executed.

Processor Pentium 4 processor uses a 2.3 MHz

clock. Clock oscillates at 2,300,000 cycles/sec Most instructions take about 5 cycles 2,300,000/5 ~ 460,000 instructions are

executed per second Even though a processor is executing

one instruction at a time, user interaction is very smooth.

Execution Process

1) Program is loaded into memory from external storage (hard drive, floppy disk.)

2) Processor executes instructions from memory

Execution

Can the processor understand C code?

Can it execute C code?

Compilation The processor cannot understand most

high level languages such as C. Need to translate C code to assembly

code. Assembly code corresponds to actual

numeric values for the instructions that the processor can understand.

A compiler is used to translate code written in C to assembly code, so that the processor can understand it.

Demo

Compile program in Visual Studio and see the assembly code.

Comparison

Is it better to program in a high level language like C?

Or assembly code?

Comparison

Pros : High Level language Easy to use, Easy to debug, Quickly develop programs

Cons : Depend on compiler to produce code May not be efficient

Comparison

Pros : Assembly Code Can write very efficient, optimal code Can utilize the full functionalities of the

processor Cons :

Hard to write code, hard to debug Requires knowledge of the architecture

of the processor that you are using

Conclusion

Main Components of a Computer Processor, Memory, External devices

Memory Temporary holding area for

instructions Processor

Executes instructions

Conclusion

Program Execution Load instructions to memory Processor executes instructions

Compilation Compiler translates high level

language to assembly

Conclusion

High level language or Assembly use depends upon application