Tomas: Could you share some background what code depends on new added APIs?
Thanks Liming >-----Original Message----- >From: edk2-devel [mailto:[email protected]] On Behalf Of >Tomas Pilar (tpilar) >Sent: Friday, June 29, 2018 5:42 PM >To: [email protected] >Subject: [edk2] [PATCH] MdePkg/BaseLib: Add bit field Hamming weight >calculation methods > >Add 32-bit and 64-bit functions that count number of set bits in a bitfield >using the divide-and-count method. > >Contributed-under: TianoCore Contribution Agreement 1.1 >Signed-off-by: Tomas Pilar <[email protected]> >--- > MdePkg/Include/Library/BaseLib.h | 56 +++++++++++++++++++++++++++ > MdePkg/Library/BaseLib/BitField.c | 79 >+++++++++++++++++++++++++++++++++++++++ > 2 files changed, 135 insertions(+) > >diff --git a/MdePkg/Include/Library/BaseLib.h >b/MdePkg/Include/Library/BaseLib.h >index 1db3a04..7eb0488 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 >+BitFieldHammingWeight32 ( >+ 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 >+BitFieldHammingWeight64 ( >+ 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..af06db8 100644 >--- a/MdePkg/Library/BaseLib/BitField.c >+++ b/MdePkg/Library/BaseLib/BitField.c >@@ -920,3 +920,82 @@ 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 >+BitFieldHammingWeight32 ( >+ IN UINT32 Operand, >+ IN UINTN StartBit, >+ IN UINTN EndBit >+ ) >+{ >+ ASSERT (EndBit < 32); >+ ASSERT (StartBit <= EndBit); >+ >+ UINT32 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 >+BitFieldHammingWeight64 ( >+ IN UINT64 Operand, >+ IN UINTN StartBit, >+ IN UINTN EndBit >+ ) >+{ >+ ASSERT (EndBit < 64); >+ ASSERT (StartBit <= EndBit); >+ >+ UINT64 BitField = BitFieldRead64 (Operand, StartBit, EndBit); >+ UINT8 Count = BitFieldHammingWeight32 (BitField, 0, 31); >+ return Count + BitFieldHammingWeight32(RShiftU64(BitField, 32), 0, 31); >+} >+ >-- >2.9.5 > >_______________________________________________ >edk2-devel mailing list >[email protected] >https://lists.01.org/mailman/listinfo/edk2-devel _______________________________________________ edk2-devel mailing list [email protected] https://lists.01.org/mailman/listinfo/edk2-devel
