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Trying to convert a string to an integer adds an extra 0 on x86_64 assembly (self.programming)

submitted 9 months ago by prettydarknwild to c/[email protected]

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I created this function for converting a string taken from standard input to an integer:

str2int:
    mov rax, 0

    L2:
        cmp byte [input + r10], 0
        je done2

        add al, [input + r10]
        sub rax, '0'
        imul rax, 10

        inc r10
        jmp L2

    done2:
    ret

but when i use it, it adds an extra 0 at the end of the number (example: a 1 gets turned into a 10, a 30 into a 300 and so), what is the problem with it?

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[–] BenM2023 1 points 9 months ago

Even I, who haven't looked at asy for very many years, and when I did I was no asy programmer, can see the problem.

I don't want to do homework so not posting the answer but my top tip for discovering the bug is to step through your code on paper...