Re: [Qemu-devel] [RFC/experimental patch] qemu (x86_64 on x86_64 -no-kqemu) compiles with gcc4 and works

[Axel Zeuner]

Hi Paul,
On Tuesday 27 March 2007 00:53, Paul Brook wrote:
> > > I moved to helper2.c because AFAICT helper.c is compiled with the same
> > > sort of restrictions as op.c which leads to the compile failure.
> >
> > Yes, helper.c is compiled with the global register variables and the code
> > is called directly from the op_xxx functions, but one needs the global
> > register variables to access global data, these contain the required
> > environment for the emulation. AFAIK helper2.c is used by the CODE_COPY
> > branch on i386 with even stronger restrictions, but I may be wrong here.
>
> helper.c is compiled with the same setting as op.c, so has direct access to
> the dyngen state ("T0", "env" etc). helper2.c is regular code. Either may
> be used from op.c, the difference is whether all arguments are explicit.
> Also, if a helper throws an exception it must be in helper.c to avoid
> clobbering CPU state before calling raise_exception.

Thank you for the clarification, I was wrong. 

Kind regards
Axel

> Note that some targets use a different naming scheme. They use helper.c for
> regular code and op_helper.c for op.c-like code. IMHO this is a much better
> naming scheme.
>
> Paul