Evaluate Expression, Assembly

Evaluate Expression

sys_exit equ 1
sys_read equ 3
sys_write equ 4

stdin equ 0
stdout equ 1

section .data
    endl db 0xA

section .bss
    arg1: resb 1
    arg2: resb 2
    operator: resb 1
    char: resb 1

section .text
global _start
    _start:
        beginReadingLoop:
            ; read a single character
            mov eax, sys_read
            mov ebx, stdout
            mov ecx, char
            mov edx, 1
            int 0x80
            
            ; store character inside al register for using cmp
            mov al, [char]
            
            ; check what the character is and go to corresponding tag
            ; read arg1, then read the operator, then read the arg2 before evaluation
            cmp al, '.'
            je end
            
            cmp al, ' '
            je beginReadingLoop
            
            cmp al, 10 ; LF (Line Feed)
            je beginReadingLoop
            
            cmp al, '0'
            jge readArgument
            
            readArgument:
                cmp al, '9'
                jg beginReadingLoop ; make sure it is actually something from 0 to 9.
                
                mov al, [arg1]
                
                
            
            cmp al, '+'
            je addition
            
            cmp al, '-'
            je subtraction
            
            cmp al, '*'
            je multiplication
            
            cmp al, '/'
            je division
            
            cmp al, '\'
            je division
            
            addition:
                
            subtraction:
                
            multiplication:
                
            division:
                
        
    end:
    
        int 0x80
        mov eax, sys_exit
        xor ebx, ebx
        int 0x80


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