1 /** @file 2 Implementation of the EfiSetMem routine. This function is broken 3 out into its own source file so that it can be excluded from a 4 build for a particular platform easily if an optimized version 5 is desired. 6 7 Copyright (c) 2006 - 2010, Intel Corporation. All rights reserved.<BR> 8 Copyright (c) 2012 - 2013, ARM Ltd. All rights reserved.<BR> 9 Copyright (c) 2016, Linaro Ltd. All rights reserved.<BR> 10 11 This program and the accompanying materials 12 are licensed and made available under the terms and conditions of the BSD License 13 which accompanies this distribution. The full text of the license may be found at 14 http://opensource.org/licenses/bsd-license.php. 15 16 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, 17 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. 18 19 **/ 20 21 22 23 24 #include "MemLibInternals.h" 25 26 /** 27 Set Buffer to Value for Size bytes. 28 29 @param Buffer The memory to set. 30 @param Length The number of bytes to set. 31 @param Value The value of the set operation. 32 33 @return Buffer 34 35 **/ 36 VOID * 37 EFIAPI 38 InternalMemSetMem ( 39 OUT VOID *Buffer, 40 IN UINTN Length, 41 IN UINT8 Value 42 ) 43 { 44 // 45 // Declare the local variables that actually move the data elements as 46 // volatile to prevent the optimizer from replacing this function with 47 // the intrinsic memset() 48 // 49 volatile UINT8 *Pointer8; 50 volatile UINT32 *Pointer32; 51 volatile UINT64 *Pointer64; 52 UINT32 Value32; 53 UINT64 Value64; 54 55 if ((((UINTN)Buffer & 0x7) == 0) && (Length >= 8)) { 56 // Generate the 64bit value 57 Value32 = (Value << 24) | (Value << 16) | (Value << 8) | Value; 58 Value64 = LShiftU64 (Value32, 32) | Value32; 59 60 Pointer64 = (UINT64*)Buffer; 61 while (Length >= 8) { 62 *(Pointer64++) = Value64; 63 Length -= 8; 64 } 65 66 // Finish with bytes if needed 67 Pointer8 = (UINT8*)Pointer64; 68 } else if ((((UINTN)Buffer & 0x3) == 0) && (Length >= 4)) { 69 // Generate the 32bit value 70 Value32 = (Value << 24) | (Value << 16) | (Value << 8) | Value; 71 72 Pointer32 = (UINT32*)Buffer; 73 while (Length >= 4) { 74 *(Pointer32++) = Value32; 75 Length -= 4; 76 } 77 78 // Finish with bytes if needed 79 Pointer8 = (UINT8*)Pointer32; 80 } else { 81 Pointer8 = (UINT8*)Buffer; 82 } 83 while (Length-- > 0) { 84 *(Pointer8++) = Value; 85 } 86 return Buffer; 87 } 88
