Re: [PATCH 1/2] MdeModulePkg/PciBusDxe: Prevent truncating constant values.

[Laszlo Ersek <lersek@redhat.com>]

On 02/27/18 17:49, Marvin Häuser wrote:
> The toolcahin VS2015x86 issues warnings when truncating constant
> values. Explicitely cast such to avoid it.
> 
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Marvin Haeuser <Marvin.Haeuser@outlook.com>
> ---
>  MdeModulePkg/Bus/Pci/PciBusDxe/PciResourceSupport.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/MdeModulePkg/Bus/Pci/PciBusDxe/PciResourceSupport.c b/MdeModulePkg/Bus/Pci/PciBusDxe/PciResourceSupport.c
> index 2f713fcee95e..a752853f3e9e 100644
> --- a/MdeModulePkg/Bus/Pci/PciBusDxe/PciResourceSupport.c
> +++ b/MdeModulePkg/Bus/Pci/PciBusDxe/PciResourceSupport.c
> @@ -1936,7 +1936,7 @@ ProgramP2C (
>                     &BridgeControl
>                     );
>  
> -      BridgeControl &= (UINT16) ~PCI_CARD_PREFETCHABLE_MEMORY_0_ENABLE;
> +      BridgeControl &= (UINT16) ~(UINT16)PCI_CARD_PREFETCHABLE_MEMORY_0_ENABLE;
>        PciIo->Pci.Write (
>                     PciIo,
>                     EfiPciIoWidthUint16,
> @@ -2005,7 +2005,7 @@ ProgramP2C (
>                     &BridgeControl
>                     );
>  
> -      BridgeControl &= (UINT16) ~(PCI_CARD_PREFETCHABLE_MEMORY_1_ENABLE);
> +      BridgeControl &= (UINT16) ~(UINT16)(PCI_CARD_PREFETCHABLE_MEMORY_1_ENABLE);
>        PciIo->Pci.Write (
>                     PciIo,
>                     EfiPciIoWidthUint16,
> 

My recommendation is the same as for:

  [edk2] [PATCH 2/2] MdeModulePkg/BaseSerialPortLib16550: Prevent
                     truncating constant values.

#define PCI_CARD_PREFETCHABLE_MEMORY_0_ENABLE BIT8
#define PCI_CARD_PREFETCHABLE_MEMORY_1_ENABLE BIT9

#define  BIT8     0x00000100
#define  BIT9     0x00000200

So I suggest (UINT32) for the casts.


I'd also suggest a better subject line / commit message. Can we say:

  Package/Module: avoid bit-negating signed integer constants

and then the commit message could quote the VS2015x86 warnings.

Again, just my two cents; I defer to the MdeModulePkg maintainers.

Thanks!
Laszlo