diff options
Diffstat (limited to 'MdePkg/Library/BaseLib/BitField.c')
| -rw-r--r-- | MdePkg/Library/BaseLib/BitField.c | 116 |
1 files changed, 98 insertions, 18 deletions
diff --git a/MdePkg/Library/BaseLib/BitField.c b/MdePkg/Library/BaseLib/BitField.c index 5a8ccff4e89d..e2098baa875f 100644 --- a/MdePkg/Library/BaseLib/BitField.c +++ b/MdePkg/Library/BaseLib/BitField.c @@ -1,14 +1,8 @@ /** @file Bit field functions of BaseLib. - Copyright (c) 2006 - 2013, Intel Corporation. All rights reserved.<BR> - This program and the accompanying materials - are licensed and made available under the terms and conditions of the BSD License - which accompanies this distribution. The full text of the license may be found at - http://opensource.org/licenses/bsd-license.php. - - THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, - WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. + Copyright (c) 2006 - 2018, Intel Corporation. All rights reserved.<BR> + SPDX-License-Identifier: BSD-2-Clause-Patent **/ @@ -69,13 +63,13 @@ InternalBaseLibBitFieldOrUint ( ) { // - // Higher bits in OrData those are not used must be zero. + // Higher bits in OrData those are not used must be zero. // // EndBit - StartBit + 1 might be 32 while the result right shifting 32 on a 32bit integer is undefined, // So the logic is updated to right shift (EndBit - StartBit) bits and compare the last bit directly. // ASSERT ((OrData >> (EndBit - StartBit)) == ((OrData >> (EndBit - StartBit)) & 1)); - + // // ~((UINTN)-2 << EndBit) is a mask in which bit[0] thru bit[EndBit] // are 1's while bit[EndBit + 1] thru the most significant bit are 0's. @@ -111,7 +105,7 @@ InternalBaseLibBitFieldAndUint ( ) { // - // Higher bits in AndData those are not used must be zero. + // Higher bits in AndData those are not used must be zero. // // EndBit - StartBit + 1 might be 32 while the result right shifting 32 on a 32bit integer is undefined, // So the logic is updated to right shift (EndBit - StartBit) bits and compare the last bit directly. @@ -275,7 +269,7 @@ BitFieldAnd8 ( bitwise OR, and returns the result. Performs a bitwise AND between the bit field specified by StartBit and EndBit - in Operand and the value specified by AndData, followed by a bitwise + in Operand and the value specified by AndData, followed by a bitwise OR with value specified by OrData. All other bits in Operand are preserved. The new 8-bit value is returned. @@ -467,7 +461,7 @@ BitFieldAnd16 ( bitwise OR, and returns the result. Performs a bitwise AND between the bit field specified by StartBit and EndBit - in Operand and the value specified by AndData, followed by a bitwise + in Operand and the value specified by AndData, followed by a bitwise OR with value specified by OrData. All other bits in Operand are preserved. The new 16-bit value is returned. @@ -659,7 +653,7 @@ BitFieldAnd32 ( bitwise OR, and returns the result. Performs a bitwise AND between the bit field specified by StartBit and EndBit - in Operand and the value specified by AndData, followed by a bitwise + in Operand and the value specified by AndData, followed by a bitwise OR with value specified by OrData. All other bits in Operand are preserved. The new 32-bit value is returned. @@ -809,7 +803,7 @@ BitFieldOr64 ( ASSERT (EndBit < 64); ASSERT (StartBit <= EndBit); // - // Higher bits in OrData those are not used must be zero. + // Higher bits in OrData those are not used must be zero. // // EndBit - StartBit + 1 might be 64 while the result right shifting 64 on RShiftU64() API is invalid, // So the logic is updated to right shift (EndBit - StartBit) bits and compare the last bit directly. @@ -857,11 +851,11 @@ BitFieldAnd64 ( { UINT64 Value1; UINT64 Value2; - + ASSERT (EndBit < 64); ASSERT (StartBit <= EndBit); // - // Higher bits in AndData those are not used must be zero. + // Higher bits in AndData those are not used must be zero. // // EndBit - StartBit + 1 might be 64 while the right shifting 64 on RShiftU64() API is invalid, // So the logic is updated to right shift (EndBit - StartBit) bits and compare the last bit directly. @@ -879,7 +873,7 @@ BitFieldAnd64 ( bitwise OR, and returns the result. Performs a bitwise AND between the bit field specified by StartBit and EndBit - in Operand and the value specified by AndData, followed by a bitwise + in Operand and the value specified by AndData, followed by a bitwise OR with value specified by OrData. All other bits in Operand are preserved. The new 64-bit value is returned. @@ -920,3 +914,89 @@ 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; +} + |