On Wed, Sep 14, 2016 at 05:14:19PM +0000, Kinney, Michael D wrote: > MdePkg/Include/Library/UefiLib.h does have some helper macros for > setting timer events periods that are in 100 nS units: > > #define EFI_TIMER_PERIOD_MICROSECONDS(Microseconds) > MultU64x32((UINT64)(Microseconds), 10) > #define EFI_TIMER_PERIOD_MILLISECONDS(Milliseconds) > MultU64x32((UINT64)(Milliseconds), 10000) > #define EFI_TIMER_PERIOD_SECONDS(Seconds) > MultU64x32((UINT64)(Seconds), 10000000) > > I believe the examples you show are for use with the gBS->Stall() > service which is in 1 uS units.
Correct. > Maybe we should consider some additional macros in UefiLib.h > > #define EFI_STALL_PERIOD_MICROSECONDS(Microseconds) (Microseconds) > #define EFI_STALL_PERIOD_MILLISECONDS(Milliseconds) ((Milliseconds) * 1000) > #define EFI_STALL_PERIOD_SECONDS(Seconds) ((Seconds) * 1000000) > > Or maybe some macros that actually do the call to gBS->Stall() too. > > #define EFI_STALL_MICROSECONDS(Microseconds) gBS->Stall (Microseconds) > #define EFI_STALL_MILLISECONDS(Milliseconds) gBS->Stall ((Milliseconds) * > 1000) > #define EFI_STALL_SECONDS(Seconds) gBS->Stall ((Seconds) * > 1000000) > Either (or both) of those two look good to me. The latter has the benefit of a smaller call site, at the cost of perhaps obscuring the dependency on UefiRuntimeServicesTableLib. > The other method of generating timed delays for PEI/DXE/SMM modules > is using the Services in MdePkg/Include/Library/TimerLib.h: > > UINTN > EFIAPI > NanoSecondDelay ( > IN UINTN NanoSeconds > ); > > UINTN > EFIAPI > MicroSecondDelay ( > IN UINTN MicroSeconds > ); > > If we wanted macros helper to use these services to match UEFI ones, maybe > add the following to TimerLib.h: > > #define DELAY_NANOSECONDS(Nanoseconds) NanoSecondDelay (Nanoseconds) > #define DELAY_MICROSECONDS(Microseconds) MicroSecondDelay (Microseconds) > #define DELAY_MILLISECONDS(Milliseconds) MicroSecondDelay ((Microseconds) * > 1000) > #define DELAY_SECONDS(Seconds) MicroSecondDelay ((Microseconds) * > 1000000) I'm less concerned about those, but it could make sense for completeness. > Do you think it would improve the maintenance of the code if macros > like these were used consistently? It would certainly be good to reduce duplication, and consistency would help with the readability of the code. (Which is good for reviewing.) Regards, Leif _______________________________________________ edk2-devel mailing list edk2-devel@lists.01.org https://lists.01.org/mailman/listinfo/edk2-devel
