Inline ASM in .c file is specific to MS tool-chain. Other tool-chain (such as Intel compiler) may not support it. Add in .asm files to make these function to be built by Assembler so that they are avaliable too for other tool-chain.

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@5529 6f19259b-4bc3-4df7-8a09-765794883524

EdkCompatibilityPkg/Foundation/Library/EfiCommonLib/Ia32/Log2.asm

@@ -0,0 +1,81 @@
+;/*++
+;
+;Copyright (c) 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:
+;
+;  Log2.c
+;
+;Abstract:
+;
+;  64-bit integer logarithm function for IA-32
+;
+;--*/
+;
+;---------------------------------------------------------------------------
+    .686
+    .model  flat,C
+    .code
+
+;---------------------------------------------------------------------------
+
+;UINT8
+;Log2 (
+;  IN UINT64   Operand
+;  )
+;/*++
+;
+;Routine Description:
+; 
+;  Calculates and floors logarithms based on 2
+;
+;Arguments:
+;
+;  Operand - value to calculate logarithm
+;  
+;Returns:
+;
+;  The largest integer that is less than or equal
+;  to the logarithm of Operand based on 2 
+;
+;--*/
+Log2 PROC
+  mov    ecx, 64
+  
+  cmp    dword ptr [esp + 4], 0  ; (UINT32 *(&Operand))
+  jne    _Log2_Wend 
+  cmp    dword ptr [esp + 8], 0  ; (UINT32 *(&Operand)) + 1
+  jne    _Log2_Wend 
+  mov    cl, 0FFH
+  jmp    _Log2_Done
+  
+_Log2_Wend:
+  dec    ecx
+  cmp    ecx, 32
+  jae    _Log2_Higher
+  bt     [esp + 4], ecx ; (UINT32 *(&Operand))
+  jmp    _Log2_Bit
+  
+_Log2_Higher:
+  mov    eax, ecx
+  sub    eax, 32
+  bt     [esp + 8], eax ; (UINT32 *(&Operand)) + 1
+  
+_Log2_Bit:
+  jc     _Log2_Done
+  jmp    _Log2_Wend
+      
+_Log2_Done:
+  mov    al, cl
+
+  ret
+
+	Log2 ENDP
+	END