From: "Gao, Liming" <liming.gao@intel.com>
To: "Tomas Pilar (tpilar)" <tpilar@solarflare.com>,
"edk2-devel@lists.01.org" <edk2-devel@lists.01.org>
Cc: "Kinney, Michael D" <michael.d.kinney@intel.com>
Subject: Re: [PATCH v4] MdePkg/BaseLib: Add bit field population calculating methods
Date: Mon, 9 Jul 2018 02:20:46 +0000 [thread overview]
Message-ID: <4A89E2EF3DFEDB4C8BFDE51014F606A14E2B7794@SHSMSX104.ccr.corp.intel.com> (raw)
In-Reply-To: <c23bb7de-b2a3-af15-be2d-ef0124b83134@solarflare.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>
>-----Original Message-----
>From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org] On Behalf Of
>Tomas Pilar (tpilar)
>Sent: Friday, July 06, 2018 9:41 PM
>To: edk2-devel@lists.01.org
>Cc: Kinney, Michael D <michael.d.kinney@intel.com>; Gao, Liming
><liming.gao@intel.com>
>Subject: [edk2] [PATCH v4] MdePkg/BaseLib: Add bit field population
>calculating methods
>
>Hopefully this should tidy the conversion warnings.
>
>----
>
>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 | 86
>+++++++++++++++++++++++++++++++++++++++
> 2 files changed, 142 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..645a662 100644
>--- a/MdePkg/Library/BaseLib/BitField.c
>+++ b/MdePkg/Library/BaseLib/BitField.c
>@@ -920,3 +920,89 @@ 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
>+ )
>+{
>+ UINT64 BitField;
>+ UINT8 Count;
>+
>+ ASSERT (EndBit < 64);
>+ ASSERT (StartBit <= EndBit);
>+
>+ BitField = BitFieldRead64 (Operand, StartBit, EndBit);
>+ Count = BitFieldCountOnes32 ((UINT32) BitField, 0, 31);
>+ Count += BitFieldCountOnes32 ((UINT32) RShiftU64(BitField, 32), 0, 31);
>+
>+ return Count;
>+}
>+
>--
>2.9.5
>
>_______________________________________________
>edk2-devel mailing list
>edk2-devel@lists.01.org
>https://lists.01.org/mailman/listinfo/edk2-devel
next prev parent reply other threads:[~2018-07-09 2:20 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-06 13:40 [PATCH v4] MdePkg/BaseLib: Add bit field population calculating methods Tomas Pilar (tpilar)
2018-07-09 2:20 ` Gao, Liming [this message]
2018-07-09 2:31 ` Gao, Liming
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