How to write an assembly language program:
These are the steps that should be followed for writing an assembly language program:
First, define the problem
Write the algorithm
Translate into assembly mnemonics
Test and Debug the program in case of errors
The translation phase consists of the following steps:
Define type of data the program will deal with
Write appropriate instructions to implement the algorithm
In this example you are asked to write a program that
calculates the average of two numbers.
Write the algorithm:
- add maximum temp and minimum temp to get the sum
- divide sum by 2 to get average
Translate into Assembly:
what is our data?
what are our initialization steps?
Here is the listing of the program as it should be given to the computer.
It should of course first be assembled and linked.
|Program that calculates the average of 2 numbers|
max_temp DB 92h
min_temp DB 52h
avg_temp DB ?
mov al, max_temp
add al, min_temp
mov ah, 00h
adc ah, 00h
mov bl, 02h
mov avg_temp, al
As a general rule, no program is supposed to work as one would expect when
it is run for the first time.
Therefore, a debugging phase, in which you have to find and correct
errors is necessary.
Here are some tips to help you go through the debugging phase.
| ||Be sure to work out an algorithm first…not as you go along
| ||write and test sections of a larger program, rather than waiting
until you think you’re done to do any testing
| ||make sure you coded according to a correct algorithm
| ||add a set of eyes or watches
| ||use a debugger such as the codeview that you use in the lab.
| ||single step through code
| ||strategically place breakpoints