1 #/*++ 2 # 3 #Copyright (c) 2006, Intel Corporation. All rights reserved.<BR> 4 #This program and the accompanying materials 5 #are licensed and made available under the terms and conditions of the BSD License 6 #which accompanies this distribution. The full text of the license may be found at 7 #http://opensource.org/licenses/bsd-license.php 8 # 9 #THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, 10 #WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. 11 # 12 #Module Name: 13 # 14 # LShiftU64.c 15 # 16 #Abstract: 17 # 18 # 64-bit left shift function for IA-32 19 # 20 #--*/ 21 # 22 #include "EfiBind.h" 23 #--------------------------------------------------------------------------- 24 .686: 25 #.MODEL flat,C 26 .code: 27 28 #--------------------------------------------------------------------------- 29 .globl ASM_PFX(LShiftU64) 30 # 31 #UINT64 32 #LShiftU64 ( 33 # IN UINT64 Operand, 34 # IN UINTN Count 35 # ) 36 #/*++ 37 # 38 #Routine Description: 39 # 40 # This routine allows a 64 bit value to be left shifted by 32 bits and 41 # returns the shifted value. 42 # Count is valid up 63. (Only Bits 0-5 is valid for Count) 43 # 44 #Arguments: 45 # 46 # Operand - Value to be shifted 47 # Count - Number of times to shift left. 48 # 49 #Returns: 50 # 51 # Value shifted left identified by the Count. 52 # 53 #--*/ 54 ASM_PFX(LShiftU64): 55 56 movl 4(%esp), %eax # dword ptr Operand[0] 57 movl 8(%esp), %edx # dword ptr Operand[4] 58 59 # 60 # CL is valid from 0 - 31. shld will move EDX:EAX by CL times but EAX is not touched 61 # For CL of 32 - 63, it will be shifted 0 - 31 so we will move eax to edx later. 62 # 63 movl 0xC(%esp), %ecx # Count 64 andl $63, %ecx 65 shld %cl, %eax, %edx 66 shlb %cl, %eax 67 68 # 69 # Since Count is 32 - 63, eax will have been shifted by 0 - 31 70 # If shifted by 32 or more, set lower 32 bits to zero. 71 # 72 cmpl $32, %ecx 73 jc _LShiftU64_Done 74 75 movl %eax, %edx 76 xorl %eax, %eax 77 78 _LShiftU64_Done: 79 80 ret 81 #LShiftU64 ENDP 82 83
