Messages in this thread | | | Date | Thu, 11 Dec 2003 00:20:14 -0800 | From | Paul Menage <> | Subject | Re: [ACPI] ACPI global lock macros |
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Yu, Luming wrote: > > > Above code have a bug! Considering below code: > > u8 acquired = FALSE; > > ACPI_ACQUIRE_GLOBAL_LOC(acpi_gbl_common_fACS.global_lock, acquired); > if(acquired) { > .... > } > > Gcc will complain " ERROR: '%cl' not allowed with sbbl ". And I think any other compiler will > complain that too !
Oops - the version I posted differed in one character from the version that I'd compiled - I'd just used "sbb" in the working version and let the compiler figure out which version to use.
> > How about below changes to your proposal code. > > < "sbbl %0,%0" \ > < :"=r"(Acq):"r"(GLptr),"i"(~1L):"dx","ax"); \ > --- > >> "sbbl %%eax,%%eax" \ >> :"=a"(Acq):"r"(GLptr),"i"(~1L):"dx"); \
Yes, that would work too, but I don't like forcing the asm to use particular registers when there's no good reason to do so.
> > > PS. I'm very curious about how could you find this bug.
It was mainly down to the differences between the i386 and x86_64 versions, and trying to understand the reasons for those differences, and indeed how the entire set of macros worked at all.
Paul
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