Calculator

This is our mini calculator project, it’s made to deal with all mathematical operation which we use in our daily life. We take an expression from user as a string, and then we deal with all numerical and characters in this expression.

The input and output example:

Firstly, we made a cpp code -which appears in resources below- that deal with all functions that we need, after that we turn every instruction to assembly by help of reference: assembly language for x86 processors, which was really helpful to deal with jmp, cmp functions

Example of our usage:

To make a good understanding about our project:

note: String can’t be held as it is in assembly code, so we made a “buffer” which is array of 30 bytes, which held the expression that user entered.

note: The Epb is a (base pointer) register which we use to point to byte by byte in the expression which user enter -Which held in buffer- .

Notice these labels:

Sign is represent if the number is positive: represented by 1. Or negative: represented by -1.

result held the answer of entered expression, after doing all entered operations, so it’s DWord: 4bytes.

Co only represented by '1' or '2', which indicates that if co is 1, then there’s multiplication operation. If it’s '2', so it indicates that there’s a division operation, for that it’s only 2 bytes: a word.

aux it’s hold the number after multiplication/division operation.

nr is hold the number changes during operation.

Overview:

In code: we use start to represent the infinite loop in which user can use the program to write expression more than one time, by jmp to this label at the answer section at the end of program: Entering more than one expression:

Loop1 and digit sections are indicating functions which check the number of digits which entered by user and seperate digit by digit, recognise that in this section we used a special mov which is movzx to mix size of 32bit register and 16bit register:

after that, we have switch section in which we check if entered symbol is: '+','-','*','/','^','!' or other. Depending on the entered symbol we je to required label: addition, substraction, multiplication, Division, factorial, or power

Example of different inputs:

There's also psign and nsign labels which indicates positive and negative sign. in incre we only increment the value of Ebp register by one to move to next digit. also, in answer section we mov the final value to the result and show it and return to begin to retry all the program again to make user able to write many expressions as he wanted.

Finally, in error section we handle the problem of division by zero. as we told user that, there's an error by divide by zero:

We recently added:

Power which improve our simple calculator to more effective one, this addition make user able to calculate power(^) of any number and make another operations with it.

Resources:

Assembly Language for x86 Processors, 6th Edition

prentice the intel microprocessors, 8th edition

c++ code

Both cpp and assembly programs are implemented by:

Microsoft Visual Studio

Note: we included "Irvine32" liberary in our assembly program which you can find its link here