On 07/02/2010 08:37 AM, Paolo Bonzini wrote:
> The second (more real) reason is inline assembly failures, for example
> (32-bit x86):
>
> register int e asm("edi");
>
> static inline int h()
> {
> int x;
> asm volatile ("mov $0, %0" : "=D" (x));
> }
>
> int g()
> {
> int f = e;
> h();
> return e - f;
> }
>
> fails to compile because gcc cannot assign edi to %0 in h(). Some host
> headers may use assembly in a way that breaks qemu. With only one
> global register in use, however, it makes sense IMO to drop the custom
> inclusion hacks and see if anyone screams.
A few months ago I developed a patch that would allow the global env
variable to be accessed via %fs (plus a backing TLS variable), which
means that no hardware register needs to be reserved for i386.
I never quite got around to finishing it because I don't know how to
set up a segment register in Windows, and it seemed like the kind of
patch that could easily get quagmired.
Is there any interest in a patch like this? Should I try to revive it?
r~
