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Re: BUG()

On Fri, 2 Jul 2004 11:44:25 +0200, Borislav Petkov
<borislav.petkov@xxxxxxxxxxx> wrote:
> <from include/asm-i386/bug.h:12>
> 12 #if 1   /* Set to zero for a slightly smaller kernel */
> 13 #define BUG()                           \
> 14  __asm__ __volatile__(  "ud2\n"         \
> 15                         "\t.word %c0\n" \
> 16                         "\t.long %c1\n" \
> 17                          : : "i" (__LINE__), "i" (__FILE__))
[...]
> 1. what does the c mean in the constraint %c0, %c1 resp.?

I think this is not a contraint. It's a 'code'. In this case it means
that the parameters 0 and 1 should not be treated as operands, but as
(constant) data. At least that's what I understand from reading
``gcc/config/i386/i386.c'' (comment and code near the print_operand
function) from the gcc sources.

Try playing with `gcc -S` and `objdump -D` on a test file, that cleared
things up a bit for me.

More documentation on these 'codes' than the above-mentioned comment
would be interesting though.

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