| /*++ | |
| Copyright (c) 2006, Intel Corporation. All rights reserved.<BR> | |
| 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: | |
| LShiftU64.c | |
| Abstract: | |
| 64-bit left shift function for IA-32 | |
| --*/ | |
| #include "Tiano.h" | |
| UINT64 | |
| LShiftU64 ( | |
| IN UINT64 Operand, | |
| IN UINTN Count | |
| ) | |
| /*++ | |
| Routine Description: | |
| This routine allows a 64 bit value to be left 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 left. | |
| Returns: | |
| Value shifted left 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 EAX is not touched | |
| ; For CL of 32 - 63, it will be shifted 0 - 31 so we will move eax to edx later. | |
| ; | |
| mov ecx, Count | |
| and ecx, 63 | |
| shld edx, eax, cl | |
| shl eax, cl | |
| ; | |
| ; Since Count is 32 - 63, eax will have been shifted by 0 - 31 | |
| ; If shifted by 32 or more, set lower 32 bits to zero. | |
| ; | |
| cmp ecx, 32 | |
| jc short _LShiftU64_Done | |
| mov edx, eax | |
| xor eax, eax | |
| _LShiftU64_Done: | |
| } | |
| } |