On Tue, 2005-05-10 at 22:10 +0100, Paul Brook wrote:
> On Tuesday 10 May 2005 21:47, J. Mayer wrote:
> > On Mon, 2005-05-09 at 02:49 +0100, Paul Brook wrote:
> > > The attached patch fixes some trivial build problems with newer gcc on
> > > amd64. It adds FORCE_RET on load ops,
> >
> > Index: target-ppc/exec.h
> > ===================================================================
> > RCS file: /cvsroot/qemu/qemu/target-ppc/exec.h,v
> > retrieving revision 1.10
> > diff -u -p -r1.10 exec.h
> > --- target-ppc/exec.h 13 Mar 2005 17:01:22 -0000 1.10
> > +++ target-ppc/exec.h 9 May 2005 01:33:04 -0000
> > @@ -33,11 +33,7 @@ register uint32_t T2 asm(AREG3);
> > #define FT1 (env->ft1)
> > #define FT2 (env->ft2)
> >
> > -#if defined (DEBUG_OP)
> > -#define RETURN() __asm__ __volatile__("nop");
> > -#else
> > -#define RETURN() __asm__ __volatile__("");
> > -#endif
> > +#define RETURN() FORCE_RET()
> >
> > Please don't change this. This is usefull and your so-called "fix" only
> > makes debug harder.
> > Same goes for all other patches: use RETURN macro everywhere in PowerPC
> > emulation code.
>
> Ok. This slipped in from a following patch, so we can revisit it when I
> submit
> those changes. A much better way to do this is to add the NOPs in dyngen.
> Then you get nops after all ops, not just the ones that use RETURN()
A better fix would be to improve qemu disasembly routines so it can
clearly separate micro-ops when displaying generated code. Since I'm too
lazy to do this, those days, a simple nop is all I need. I think
patching dyngen for a debug-only feature is a really bad idea...
> > > and introduces helper functions for floating
> > > point negation (these require a literal constant load).
> >
> > /* fneg */
> > +void do_fneg (void);
> > PPC_OP(fneg)
> > {
> > - FT0 = -FT0;
> > + do_fneg();
> > RETURN();
> > }
> >
> > Where's the problem ? It compiles and run perfectly on my amd64. Calling
> > a function for this is a nonsense. Don't apply this.
>
> As I said it's required to avoid a pc-relative constant literal load.
> gcc4.0 compiles fneg to:
Then use the softfloat helper, but never call a function for such a
thing:
replace it with FT0 = float64_chs(FT0);
It uses a 8 bit constant with gcc3. gcc 4 should do the same, if it's
not too buggy....
--
J. Mayer <[EMAIL PROTECTED]>
Never organized
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