This is the mail archive of the
gcc-help@gcc.gnu.org
mailing list for the GCC project.
Re: specifier on operand in asm inline
Ian Lance Taylor <iant@google.com> wrote:
> dofg <dofg@ya.ru> writes:
>
> > you gave the description of the constraints
> > : "=&r" ((USItype)(r1)),
> > "=&r" ((USItype)(r0))
> > : "%rJ" ((USItype)(x3)),
> > "rI" ((USItype)(y3)),
> > i am pointing to
> > "subx %r2,%3,%%g1\n\t"
> > more definitely, to %r2. operand of subx. 'r' here is also a
> > constraint, telling compiler to use register?
>
> Oh, sorry. That's not a constraint. That's an operand modifier.
>
> For SPARC %r2 means that if the argument is the integer zero, it
> should print %g0. Otherwise it should print the operand as usual.
huge thanks.
i'm curious of other operand modifiers. can you advice any docs on them?
>
> Ian
mp