Message-ID: <36DD7DAD.3FDDFA96@unb.ca>
Date: Wed, 03 Mar 1999 14:21:33 -0400
From: Endlisnis <s257m AT unb DOT ca>
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To: djgpp AT delorie DOT com
Subject: Re: Generating Machine Code on the fly
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Reply-To: djgpp AT delorie DOT com

Paul Derbyshire wrote:

> >char *codehere;     /*void*, char* or what*/
> >codehere=(char *)malloc(100);    /* 100 bytes of code memory */
> >codehere[0]=0xc3;    /*just perform a ret operation for now*/
> >asm(
> >    "call %%ebx"    /* no comma after this */
> >    : /*no ouputs*/
> >    : b (codehere)   );
>
> Why %ebx? Why not let the compiler choose?

    No real reason, actually I can't remember how to do that, and I didn't feel
like looking it up.

> And won't this clobber %eax with output if the "codehere" code returns a
> value?

    That is something to consider, and sometimes, other registers are used.  I
think if the function returns a "long long" it is in edx:eax [I'm not sure
though].

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