Re: [PATCH v3] MdePkg/BaseLib: Add bit field population calculating methods

["Gao, Liming" <liming.gao@intel.com>]

Tom:
  When I use VS2015 to compile it, I meet with below error. Could you fix them?

Edk2\MdePkg\Library\BaseLib\BitField.c(1002): error C2220: warning treated as error - no 'object' file generated
Edk2\MdePkg\Library\BaseLib\BitField.c(1002): warning C4244: '=': conversion from 'UINT64' to 'UINT32', possible loss of data
Edk2\MdePkg\Library\BaseLib\BitField.c(1005): warning C4244: 'function': conversion from 'UINT64' to 'UINT32', possible loss of data

Thanks
Liming
> -----Original Message-----
> From: Tomas Pilar (tpilar) [mailto:tpilar@solarflare.com]
> Sent: Wednesday, July 4, 2018 10:02 PM
> To: edk2-devel@lists.01.org
> Cc: Kinney, Michael D <michael.d.kinney@intel.com>; Gao, Liming <liming.gao@intel.com>
> Subject: [PATCH v3] MdePkg/BaseLib: Add bit field population calculating methods
> 
> Add 32-bit and 64-bit functions that count number of set bits in a bitfield
> using a divide-and-count method.
> 
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Tomas Pilar <tpilar@solarflare.com>
> Cc: Liming Gao <liming.gao@intel.com>
> Cc: Michael D Kinney <michael.d.kinney@intel.com>
> ---
>  MdePkg/Include/Library/BaseLib.h  | 56 ++++++++++++++++++++++++++
>  MdePkg/Library/BaseLib/BitField.c | 85 +++++++++++++++++++++++++++++++++++++++
>  2 files changed, 141 insertions(+)
> 
> diff --git a/MdePkg/Include/Library/BaseLib.h b/MdePkg/Include/Library/BaseLib.h
> index 1db3a04..123ae19 100644
> --- a/MdePkg/Include/Library/BaseLib.h
> +++ b/MdePkg/Include/Library/BaseLib.h
> @@ -4609,6 +4609,62 @@ BitFieldAndThenOr64 (
>    IN      UINT64                    OrData
>    );
> 
> +/**
> +  Reads a bit field from a 32-bit value, counts and returns
> +  the number of set bits.
> +
> +  Counts the number of set bits in the  bit field specified by
> +  StartBit and EndBit in Operand. The count is returned.
> +
> +  If StartBit is greater than 31, then ASSERT().
> +  If EndBit is greater than 31, then ASSERT().
> +  If EndBit is less than StartBit, then ASSERT().
> +
> +  @param  Operand   Operand on which to perform the bitfield operation.
> +  @param  StartBit  The ordinal of the least significant bit in the bit field.
> +                    Range 0..31.
> +  @param  EndBit    The ordinal of the most significant bit in the bit field.
> +                    Range 0..31.
> +
> +  @return The number of bits set between StartBit and EndBit.
> +
> +**/
> +UINT8
> +EFIAPI
> +BitFieldCountOnes32 (
> +  IN       UINT32                   Operand,
> +  IN       UINTN                    StartBit,
> +  IN       UINTN                    EndBit
> +  );
> +
> +/**
> +   Reads a bit field from a 64-bit value, counts and returns
> +   the number of set bits.
> +
> +   Counts the number of set bits in the  bit field specified by
> +   StartBit and EndBit in Operand. The count is returned.
> +
> +   If StartBit is greater than 63, then ASSERT().
> +   If EndBit is greater than 63, then ASSERT().
> +   If EndBit is less than StartBit, then ASSERT().
> +
> +   @param  Operand   Operand on which to perform the bitfield operation.
> +   @param  StartBit  The ordinal of the least significant bit in the bit field.
> +   Range 0..63.
> +   @param  EndBit    The ordinal of the most significant bit in the bit field.
> +   Range 0..63.
> +
> +   @return The number of bits set between StartBit and EndBit.
> +
> +**/
> +UINT8
> +EFIAPI
> +BitFieldCountOnes64 (
> +  IN       UINT64                   Operand,
> +  IN       UINTN                    StartBit,
> +  IN       UINTN                    EndBit
> +  );
> +
>  //
>  // Base Library Checksum Functions
>  //
> diff --git a/MdePkg/Library/BaseLib/BitField.c b/MdePkg/Library/BaseLib/BitField.c
> index d2d3150..8acd345 100644
> --- a/MdePkg/Library/BaseLib/BitField.c
> +++ b/MdePkg/Library/BaseLib/BitField.c
> @@ -920,3 +920,88 @@ BitFieldAndThenOr64 (
>             OrData
>             );
>  }
> +
> +/**
> +  Reads a bit field from a 32-bit value, counts and returns
> +  the number of set bits.
> +
> +  Counts the number of set bits in the  bit field specified by
> +  StartBit and EndBit in Operand. The count is returned.
> +
> +  If StartBit is greater than 31, then ASSERT().
> +  If EndBit is greater than 31, then ASSERT().
> +  If EndBit is less than StartBit, then ASSERT().
> +
> +  @param  Operand   Operand on which to perform the bitfield operation.
> +  @param  StartBit  The ordinal of the least significant bit in the bit field.
> +                    Range 0..31.
> +  @param  EndBit    The ordinal of the most significant bit in the bit field.
> +                    Range 0..31.
> +
> +  @return The number of bits set between StartBit and EndBit.
> +
> +**/
> +UINT8
> +EFIAPI
> +BitFieldCountOnes32 (
> +  IN       UINT32                   Operand,
> +  IN       UINTN                    StartBit,
> +  IN       UINTN                    EndBit
> +  )
> +{
> +  UINT32 Count;
> +
> +  ASSERT (EndBit < 32);
> +  ASSERT (StartBit <= EndBit);
> +
> +  Count = BitFieldRead32 (Operand, StartBit, EndBit);
> +  Count -= ((Count >> 1) & 0x55555555);
> +  Count = (Count & 0x33333333) + ((Count >> 2) & 0x33333333);
> +  Count += Count >> 4;
> +  Count &= 0x0F0F0F0F;
> +  Count += Count >> 8;
> +  Count += Count >> 16;
> +
> +  return (UINT8) Count & 0x3F;
> +}
> +
> +/**
> +   Reads a bit field from a 64-bit value, counts and returns
> +   the number of set bits.
> +
> +   Counts the number of set bits in the  bit field specified by
> +   StartBit and EndBit in Operand. The count is returned.
> +
> +   If StartBit is greater than 63, then ASSERT().
> +   If EndBit is greater than 63, then ASSERT().
> +   If EndBit is less than StartBit, then ASSERT().
> +
> +   @param  Operand   Operand on which to perform the bitfield operation.
> +   @param  StartBit  The ordinal of the least significant bit in the bit field.
> +   Range 0..63.
> +   @param  EndBit    The ordinal of the most significant bit in the bit field.
> +   Range 0..63.
> +
> +   @return The number of bits set between StartBit and EndBit.
> +
> +**/
> +UINT8
> +EFIAPI
> +BitFieldCountOnes64 (
> +  IN       UINT64                   Operand,
> +  IN       UINTN                    StartBit,
> +  IN       UINTN                    EndBit
> +  )
> +{
> +  UINT32 BitField;
> +  UINT8 Count;
> +
> +  ASSERT (EndBit < 64);
> +  ASSERT (StartBit <= EndBit);
> +
> +  BitField = BitFieldRead64 (Operand, StartBit, EndBit);
> +  Count = BitFieldCountOnes32 (BitField, 0, 31);
> +
> +  return Count + BitFieldCountOnes32 (RShiftU64(BitField, 32), 0, 31);
> +}
> +
> --
> 2.9.5