Re: A basic question on asm

From: C (spamtrap_at_crayne.org)
Date: 09/24/04

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    Date: Fri, 24 Sep 2004 09:24:22 +0000 (UTC)

    Percival wrote:
    > Rong wrote:
    >
    >> I ran into this x86 sentence:
    >> mov %eax,(%esp,1)
    >> I am not sure what (%esp, 1) part mean.
    >> And I could not find the explanation in x86 manual.
    >> Can anyone explain a little?
    >>
    >> Thank you,
    >>
    >>
    >
    > It is AT&T syntax. I am not familiar with it, but possibly the gas
    > manual or some sort should tell you what it means.
    >
    > My *GUESS*, and only a guess, is that it is mov [esp+1], [eax] in intel
    > syntax.
    >
    > But it is only a guess. I need to learn at&T syntax soon.
    >
    > Percival

    Close, your example would be "mov %eax, 1(%esp)" in gas.
    "mov %eax, (%esp,1)" is "mov [esp], eax" the 1 being the scale
    so "mov %eax,(%ebx,2)" is "mov [ebx*2], eax".

    PS: If you are debugging with gdb you can do...

    set disassembly-flavor intel

    Which should switch to Intel style syntax. (Yes, flavour is
    ment to be misspelled.)

    C
    2004-09-24

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