44 lines
1.5 KiB
NASM
44 lines
1.5 KiB
NASM
bits 32 ; assembling for the 32 bits architecture
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; declare the EntryPoint (a label defining the very first instruction of the program)
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global start
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; declare external functions needed by our program
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extern exit,printf,scanf ; tell nasm that exit exists even if we won't be defining it
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import exit msvcrt.dll ; exit is a function that ends the calling process. It is defined in msvcrt.dll
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; msvcrt.dll contains exit, printf and all the other important C-runtime specific functions
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import printf msvcrt.dll ; printf is a function that prints a formatted string to the standard output
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import scanf msvcrt.dll ; scanf is a function that reads a formatted string from the standard input
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; our data is declared here (the variables needed by our program)
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segment data use32 class=data
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; ...
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read_number db "%d",0
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a dd 0
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b dd 0
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message db "Sum=%d",0
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; our code starts here
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segment code use32 class=code
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start:
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; ...
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; read a and b
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push dword a
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push dword read_number
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call [scanf]
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add esp, 4*2
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push dword b
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push dword read_number
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call [scanf]
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add esp, 4*2
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;print out the sum
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mov eax, [a]
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add eax, [b]
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push eax
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push dword message
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call [printf]
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add esp, 4*2
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; exit(0)
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push dword 0 ; push the parameter for exit onto the stack
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call [exit] ; call exit to terminate the program
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