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Diffstat (limited to 'EDK/Foundation/Library/EdkIIGlueLib/Library/BaseLib/LowBitSet32.c')
-rw-r--r-- | EDK/Foundation/Library/EdkIIGlueLib/Library/BaseLib/LowBitSet32.c | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/EDK/Foundation/Library/EdkIIGlueLib/Library/BaseLib/LowBitSet32.c b/EDK/Foundation/Library/EdkIIGlueLib/Library/BaseLib/LowBitSet32.c new file mode 100644 index 0000000..99ebe42 --- /dev/null +++ b/EDK/Foundation/Library/EdkIIGlueLib/Library/BaseLib/LowBitSet32.c @@ -0,0 +1,52 @@ +/*++ + +Copyright (c) 2004 - 2006, Intel Corporation +All rights reserved. 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. + + +Module Name: + + LowBitSet32.c + +Abstract: + + Math worker functions. + +--*/ + +#include "BaseLibInternal.h" + +/** + Returns the bit position of the lowest bit set in a 32-bit value. + + This function computes the bit position of the lowest bit set in the 32-bit + value specified by Operand. If Operand is zero, then -1 is returned. + Otherwise, a value between 0 and 31 is returned. + + @param Operand The 32-bit operand to evaluate. + + @return Position of the lowest bit set in Operand if found. + @retval -1 Operand is zero. + +**/ +INTN +EFIAPI +LowBitSet32 ( + IN UINT32 Operand + ) +{ + INTN BitIndex; + + if (Operand == 0) { + return -1; + } + + for (BitIndex = 0; (Operand & 1) == 0; BitIndex++, Operand >>= 1); + return BitIndex; +} |