Update the copyright notice format

[mirror_edk2.git] / EdkCompatibilityPkg / Foundation / Library / EfiCommonLib / Ia32 / Log2.c

/*++\r
\r
Copyright (c) 2006, 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
  Log2.c\r
\r
Abstract:\r
\r
  64-bit integer logarithm function for IA-32\r
\r
--*/\r
\r
#include "Tiano.h"\r
\r
UINT8\r
Log2 (\r
  IN UINT64   Operand\r
  )\r
/*++\r
\r
Routine Description:\r
 \r
  Calculates and floors logarithms based on 2\r
\r
Arguments:\r
\r
  Operand - value to calculate logarithm\r
  \r
Returns:\r
\r
  The largest integer that is less than or equal\r
  to the logarithm of Operand based on 2 \r
\r
--*/\r
{\r
  __asm {\r
  mov    ecx, 64\r
  \r
  cmp    dword ptr Operand[0], 0\r
  jne    _Log2_Wend \r
  cmp    dword ptr Operand[4], 0\r
  jne    _Log2_Wend \r
  mov    cl, 0FFH\r
  jmp    _Log2_Done\r
  \r
_Log2_Wend:\r
  dec    ecx\r
  cmp    ecx, 32\r
  jae    _Log2_Higher\r
  bt     dword ptr Operand[0], ecx\r
  jmp    _Log2_Bit\r
  \r
_Log2_Higher:\r
  mov    eax, ecx\r
  sub    eax, 32\r
  bt     dword ptr Operand[4], eax\r
  \r
_Log2_Bit:\r
  jc     _Log2_Done\r
  jmp    _Log2_Wend\r
      \r
_Log2_Done:\r
  mov    al, cl\r
  }\r
}\r