Sync all bug fixes between EDK1.04 and EDK1.06 into EdkCompatibilityPkg.

[mirror_edk2.git] / EdkCompatibilityPkg / Foundation / Library / EfiCommonLib / Math.c

/*++\r
\r
Copyright (c) 2004 - 2010, 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
Module Name:\r
\r
  Math.c\r
\r
Abstract:\r
\r
  Math worker functions. \r
\r
--*/\r
\r
#include "Tiano.h"\r
\r
UINT64\r
LShiftU64 (\r
  IN UINT64   Operand,\r
  IN UINTN    Count\r
  )\r
/*++\r
\r
Routine Description:\r
\r
  This routine allows a 64 bit value to be left shifted by 32 bits and \r
  returns the shifted value.\r
  Count is valid up 63. (Only Bits 0-5 is valid for Count)\r
\r
Arguments:\r
\r
  Operand - Value to be shifted\r
  Count   - Number of times to shift left.\r
 \r
Returns:\r
\r
  Value shifted left identified by the Count.\r
\r
--*/\r
{\r
  return Operand << Count;\r
}\r
\r
UINT64\r
MultU64x32 (\r
  IN UINT64   Multiplicand,\r
  IN UINTN    Multiplier\r
  )\r
/*++  \r
  \r
Routine Description:\r
\r
  This routine allows a 64 bit value to be multiplied with a 32 bit \r
  value returns 64bit result.\r
  No checking if the result is greater than 64bits\r
\r
Arguments:\r
\r
  Multiplicand  - multiplicand\r
  Multiplier    - multiplier\r
\r
Returns:\r
\r
  Multiplicand * Multiplier\r
  \r
--*/\r
{\r
  return Multiplicand * Multiplier;\r
}\r
\r
UINT64\r
Power10U64 (\r
  IN UINT64   Operand,\r
  IN UINTN    Power\r
  )\r
{\r
  UINT64 Result;\r
\r
  Result = Operand;\r
  while (Power-- > 0) {\r
    Result *= 10;\r
  }\r
  return Result;\r
}\r
\r
UINT64\r
RShiftU64 (\r
  IN UINT64   Operand,\r
  IN UINTN    Count\r
  )\r
/*++\r
\r
Routine Description:\r
\r
  This routine allows a 64 bit value to be right shifted by 32 bits and returns the \r
  shifted value.\r
  Count is valid up 63. (Only Bits 0-5 is valid for Count)\r
\r
Arguments:\r
\r
  Operand - Value to be shifted\r
  Count   - Number of times to shift right.\r
 \r
Returns:\r
\r
  Value shifted right identified by the Count.\r
\r
--*/\r
{\r
  return Operand >> Count;\r
}\r
\r
UINT64\r
DivU64x32 (\r
  IN UINT64   Dividend,\r
  IN UINTN    Divisor,\r
  OUT UINTN   *Remainder OPTIONAL\r
  )\r
/*++\r
\r
Routine Description:\r
\r
  This routine allows a 64 bit value to be divided with a 32 bit value returns \r
  64bit result and the Remainder.\r
\r
Arguments:\r
\r
  Dividend  - dividend\r
  Divisor   - divisor\r
  Remainder - buffer for remainder\r
 \r
Returns:\r
\r
  Dividend  / Divisor\r
  Remainder = Dividend mod Divisor\r
\r
--*/\r
{\r
  if (Remainder != NULL) {\r
    *Remainder = Dividend % Divisor;\r
  }\r
\r
  return Dividend / Divisor;\r
}\r
\r
UINT8\r
Log2 (\r
  IN UINT64   Operand\r
  )\r
/*++\r
\r
Routine Description:\r
\r
  This function computes rounded down log2 of the Operand.  This is an equivalent\r
  of the position of the highest bit set in the Operand treated as a mask.\r
  E.g., Log2 (0x0001) == 0, Log2 (0x0002) == 1, Log2 (0x0003) == 1, Log2 (0x0005) == 2\r
  Log2 (0x4000) == 14, Log2 (0x8000) == 15, Log2 (0xC000) == 15, Log2 (0xFFFF) == 15, etc.\r
\r
Arguments:\r
  Operand - value of which the Log2 is to be computed.\r
\r
Returns:\r
  Rounded down log2 of the Operand or 0xFF if zero passed in.\r
\r
--*/\r
{\r
  UINT8 Bitpos;\r
  Bitpos = 0;\r
\r
  if (Operand == 0) {\r
    return (0xff);\r
  }\r
\r
  while (Operand != 0) {\r
    Operand >>= 1;\r
    Bitpos++;\r
  }\r
  return (UINT8)(Bitpos - 1);\r
\r
}\r
\r
UINT64\r
GetPowerOfTwo (\r
  IN UINT64 Operand\r
  )\r
/*++\r
\r
Routine Description:\r
\r
  Calculates the largest integer that is both \r
  a power of two and less than Input\r
\r
Arguments:\r
\r
  Operand  - value to calculate power of two\r
\r
Returns:\r
\r
  the largest integer that is both  a power of \r
  two and less than Input\r
\r
--*/\r
{\r
  UINT8 Bitpos;\r
  Bitpos = 0;\r
\r
  if (Operand == 0) {\r
    return 0;\r
  }\r
\r
  while (Operand != 0) {\r
    Operand >>= 1;\r
    Bitpos++;\r
  }\r
\r
  Operand = 1;\r
  Bitpos--;\r
  while (Bitpos != 0) {\r
    Operand <<= 1;\r
    Bitpos--;\r
  }\r
\r
  return Operand;\r
}\r