Fixed the issue that BitFieldWrite32, BitFieldAnd32, BitFieldOr32, BitFieldAndThenOr3...

[mirror_edk2.git] / MdePkg / Library / BaseLib / BitField.c

/** @file\r
  Bit field functions of BaseLib.\r
\r
  Copyright (c) 2006 - 2013, Intel Corporation. All rights reserved.<BR>\r
  This program and the accompanying materials\r
  are licensed and made available under the terms and conditions of the BSD License\r
  which accompanies this distribution.  The full text of the license may be found at\r
  http://opensource.org/licenses/bsd-license.php.\r
\r
  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
\r
**/\r
\r
#include "BaseLibInternals.h"\r
\r
/**\r
  Worker function that returns a bit field from Operand.\r
\r
  Returns the bitfield specified by the StartBit and the EndBit from Operand.\r
\r
  @param  Operand   Operand on which to perform the bitfield operation.\r
  @param  StartBit  The ordinal of the least significant bit in the bit field.\r
  @param  EndBit    The ordinal of the most significant bit in the bit field.\r
\r
  @return The bit field read.\r
\r
**/\r
UINTN\r
EFIAPI\r
InternalBaseLibBitFieldReadUint (\r
  IN      UINTN                     Operand,\r
  IN      UINTN                     StartBit,\r
  IN      UINTN                     EndBit\r
  )\r
{\r
  //\r
  // ~((UINTN)-2 << EndBit) is a mask in which bit[0] thru bit[EndBit]\r
  // are 1's while bit[EndBit + 1] thru the most significant bit are 0's.\r
  //\r
  return (Operand & ~((UINTN)-2 << EndBit)) >> StartBit;\r
}\r
\r
/**\r
  Worker function that reads a bit field from Operand, performs a bitwise OR,\r
  and returns the result.\r
\r
  Performs a bitwise OR between the bit field specified by StartBit and EndBit\r
  in Operand and the value specified by AndData. All other bits in Operand are\r
  preserved. The new value is returned.\r
\r
  If OrData is larger than the bitmask value range specified by StartBit and EndBit, then ASSERT().\r
\r
  @param  Operand   Operand on which to perform the bitfield operation.\r
  @param  StartBit  The ordinal of the least significant bit in the bit field.\r
  @param  EndBit    The ordinal of the most significant bit in the bit field.\r
  @param  OrData    The value to OR with the read value from the value.\r
\r
  @return The new value.\r
\r
**/\r
UINTN\r
EFIAPI\r
InternalBaseLibBitFieldOrUint (\r
  IN      UINTN                     Operand,\r
  IN      UINTN                     StartBit,\r
  IN      UINTN                     EndBit,\r
  IN      UINTN                     OrData\r
  )\r
{\r
  //\r
  // Higher bits in OrData those are not used must be zero. \r
  //\r