Add in the 1st version of ECP.
git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@2832 6f19259b-4bc3-4df7-8a09-765794883524
This commit is contained in:
@@ -0,0 +1,71 @@
|
||||
/*++
|
||||
|
||||
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:
|
||||
|
||||
RShiftU64.c
|
||||
|
||||
Abstract:
|
||||
|
||||
64-bit right shift function for IA-32
|
||||
|
||||
--*/
|
||||
|
||||
#include "Tiano.h"
|
||||
|
||||
UINT64
|
||||
RShiftU64 (
|
||||
IN UINT64 Operand,
|
||||
IN UINTN Count
|
||||
)
|
||||
/*++
|
||||
|
||||
Routine Description:
|
||||
This routine allows a 64 bit value to be right shifted by 32 bits and returns the
|
||||
shifted value.
|
||||
Count is valid up 63. (Only Bits 0-5 is valid for Count)
|
||||
Arguments:
|
||||
Operand - Value to be shifted
|
||||
Count - Number of times to shift right.
|
||||
|
||||
Returns:
|
||||
|
||||
Value shifted right identified by the Count.
|
||||
|
||||
--*/
|
||||
{
|
||||
__asm {
|
||||
|
||||
mov eax, dword ptr Operand[0]
|
||||
mov edx, dword ptr Operand[4]
|
||||
|
||||
;
|
||||
; CL is valid from 0 - 31. shld will move EDX:EAX by CL times but EDX is not touched
|
||||
; For CL of 32 - 63, it will be shifted 0 - 31 so we will move edx to eax later.
|
||||
;
|
||||
mov ecx, Count
|
||||
and ecx, 63
|
||||
shrd eax, edx, cl
|
||||
shr edx, cl
|
||||
|
||||
cmp ecx, 32
|
||||
jc short _RShiftU64_Done
|
||||
|
||||
;
|
||||
; Since Count is 32 - 63, edx will have been shifted by 0 - 31
|
||||
; If shifted by 32 or more, set upper 32 bits to zero.
|
||||
;
|
||||
mov eax, edx
|
||||
xor edx, edx
|
||||
|
||||
_RShiftU64_Done:
|
||||
}
|
||||
}
|
Reference in New Issue
Block a user