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 EfiSetMem.c 15 16 Abstract: 17 18 This is the code that supports IA32-optimized SetMem service 19 20 --*/ 21 22 #include "Tiano.h" 23 24 VOID 25 EfiCommonLibSetMem ( 26 IN VOID *Buffer, 27 IN UINTN Count, 28 IN UINT8 Value 29 ) 30 /*++ 31 32 Input: VOID *Buffer - Pointer to buffer to write 33 UINTN Count - Number of bytes to write 34 UINT8 Value - Value to write 35 36 Output: None. 37 38 Saves: 39 40 Modifies: 41 42 Description: This function is an optimized set-memory function. 43 44 Notes: This function tries to set memory 8 bytes at a time. As a result, 45 it first picks up any misaligned bytes, then words, before getting 46 in the main loop that does the 8-byte clears. 47 48 --*/ 49 { 50 UINT64 QWordValue; 51 UINT64 MmxSave; 52 __asm { 53 mov edx, Count 54 test edx, edx 55 je _SetMemDone 56 57 push ebx 58 59 mov eax, Buffer 60 mov bl, Value 61 mov edi, eax 62 mov bh, bl 63 64 cmp edx, 256 65 jb _SetRemindingByte 66 67 and al, 07h 68 test al, al 69 je _SetBlock 70 71 mov eax, edi 72 shr eax, 3 73 inc eax 74 shl eax, 3 75 sub eax, edi 76 cmp eax, edx 77 jnb _SetRemindingByte 78 79 sub edx, eax 80 mov ecx, eax 81 82 mov al, bl 83 rep stosb 84 85 _SetBlock: 86 mov eax, edx 87 shr eax, 6 88 test eax, eax 89 je _SetRemindingByte 90 91 shl eax, 6 92 sub edx, eax 93 shr eax, 6 94 95 mov WORD PTR QWordValue[0], bx 96 mov WORD PTR QWordValue[2], bx 97 mov WORD PTR QWordValue[4], bx 98 mov WORD PTR QWordValue[6], bx 99 100 101 movq MmxSave, mm0 102 movq mm0, QWordValue 103 104 _B: 105 movq QWORD PTR ds:[edi], mm0 106 movq QWORD PTR ds:[edi+8], mm0 107 movq QWORD PTR ds:[edi+16], mm0 108 movq QWORD PTR ds:[edi+24], mm0 109 movq QWORD PTR ds:[edi+32], mm0 110 movq QWORD PTR ds:[edi+40], mm0 111 movq QWORD PTR ds:[edi+48], mm0 112 movq QWORD PTR ds:[edi+56], mm0 113 add edi, 64 114 dec eax 115 jnz _B 116 117 ; Restore mm0 118 movq mm0, MmxSave 119 emms ; Exit MMX Instruction 120 121 _SetRemindingByte: 122 mov ecx, edx 123 124 mov eax, ebx 125 shl eax, 16 126 mov ax, bx 127 shr ecx, 2 128 rep stosd 129 130 mov ecx, edx 131 and ecx, 3 132 rep stosb 133 134 pop ebx 135 136 _SetMemDone: 137 138 } 139 } 140
