Fw: RE: About register constraint in gcc inline assembly

["Lin Chun-Zhi" <lcz90@xxxxxxxxxxxxx>]

Thanks Ian kindly replied my question.

If you are interested in the issue, you can also refer to http://gcc.gnu.org/ml/gcc-help/2005-06/msg00019.html

Roach

> If there are no constraints, the compiler does not constrain the
> operand.  It could be anywhere.  The statement will use "service",
> though; assignments to it will not be deleted.
>
> By the way, in linux-2.6.8.1 that statement looks like this:
>
> __asm__("lcall *(%%edi); cld"
> : "=a" (return_code),
>   "=b" (address),
>   "=c" (length),
>   "=d" (entry)
> : "0" (service),
>   "1" (0),
>   "D" (&bios32_indirect));
>
> Ian