1 /* 2 * Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu> 3 * Copyright (C) 2008-2009 PetaLogix 4 * Copyright (C) 2007 John Williams 5 * 6 * Reasonably optimised generic C-code for memcpy on Microblaze 7 * This is generic C code to do efficient, alignment-aware memcpy. 8 * 9 * It is based on demo code originally Copyright 2001 by Intel Corp, taken from 10 * http://www.embedded.com/showArticle.jhtml?articleID=19205567 11 * 12 * Attempts were made, unsuccessfully, to contact the original 13 * author of this code (Michael Morrow, Intel). Below is the original 14 * copyright notice. 15 * 16 * This software has been developed by Intel Corporation. 17 * Intel specifically disclaims all warranties, express or 18 * implied, and all liability, including consequential and 19 * other indirect damages, for the use of this program, including 20 * liability for infringement of any proprietary rights, 21 * and including the warranties of merchantability and fitness 22 * for a particular purpose. Intel does not assume any 23 * responsibility for and errors which may appear in this program 24 * not any responsibility to update it. 25 */ 26 27 #include <linux/export.h> 28 #include <linux/types.h> 29 #include <linux/stddef.h> 30 #include <linux/compiler.h> 31 32 #include <linux/string.h> 33 34 #ifdef __HAVE_ARCH_MEMCPY 35 #ifndef CONFIG_OPT_LIB_FUNCTION 36 void *memcpy(void *v_dst, const void *v_src, __kernel_size_t c) 37 { 38 const char *src = v_src; 39 char *dst = v_dst; 40 41 /* Simple, byte oriented memcpy. */ 42 while (c--) 43 *dst++ = *src++; 44 45 return v_dst; 46 } 47 #else /* CONFIG_OPT_LIB_FUNCTION */ 48 void *memcpy(void *v_dst, const void *v_src, __kernel_size_t c) 49 { 50 const char *src = v_src; 51 char *dst = v_dst; 52 53 /* The following code tries to optimize the copy by using unsigned 54 * alignment. This will work fine if both source and destination are 55 * aligned on the same boundary. However, if they are aligned on 56 * different boundaries shifts will be necessary. This might result in 57 * bad performance on MicroBlaze systems without a barrel shifter. 58 */ 59 const uint32_t *i_src; 60 uint32_t *i_dst; 61 62 if (likely(c >= 4)) { 63 unsigned value, buf_hold; 64 65 /* Align the destination to a word boundary. */ 66 /* This is done in an endian independent manner. */ 67 switch ((unsigned long)dst & 3) { 68 case 1: 69 *dst++ = *src++; 70 --c; 71 fallthrough; 72 case 2: 73 *dst++ = *src++; 74 --c; 75 fallthrough; 76 case 3: 77 *dst++ = *src++; 78 --c; 79 } 80 81 i_dst = (void *)dst; 82 83 /* Choose a copy scheme based on the source */ 84 /* alignment relative to destination. */ 85 switch ((unsigned long)src & 3) { 86 case 0x0: /* Both byte offsets are aligned */ 87 i_src = (const void *)src; 88 89 for (; c >= 4; c -= 4) 90 *i_dst++ = *i_src++; 91 92 src = (const void *)i_src; 93 break; 94 case 0x1: /* Unaligned - Off by 1 */ 95 /* Word align the source */ 96 i_src = (const void *) ((unsigned)src & ~3); 97 #ifndef __MICROBLAZEEL__ 98 /* Load the holding buffer */ 99 buf_hold = *i_src++ << 8; 100 101 for (; c >= 4; c -= 4) { 102 value = *i_src++; 103 *i_dst++ = buf_hold | value >> 24; 104 buf_hold = value << 8; 105 } 106 #else 107 /* Load the holding buffer */ 108 buf_hold = (*i_src++ & 0xFFFFFF00) >> 8; 109 110 for (; c >= 4; c -= 4) { 111 value = *i_src++; 112 *i_dst++ = buf_hold | ((value & 0xFF) << 24); 113 buf_hold = (value & 0xFFFFFF00) >> 8; 114 } 115 #endif 116 /* Realign the source */ 117 src = (const void *)i_src; 118 src -= 3; 119 break; 120 case 0x2: /* Unaligned - Off by 2 */ 121 /* Word align the source */ 122 i_src = (const void *) ((unsigned)src & ~3); 123 #ifndef __MICROBLAZEEL__ 124 /* Load the holding buffer */ 125 buf_hold = *i_src++ << 16; 126 127 for (; c >= 4; c -= 4) { 128 value = *i_src++; 129 *i_dst++ = buf_hold | value >> 16; 130 buf_hold = value << 16; 131 } 132 #else 133 /* Load the holding buffer */ 134 buf_hold = (*i_src++ & 0xFFFF0000) >> 16; 135 136 for (; c >= 4; c -= 4) { 137 value = *i_src++; 138 *i_dst++ = buf_hold | ((value & 0xFFFF) << 16); 139 buf_hold = (value & 0xFFFF0000) >> 16; 140 } 141 #endif 142 /* Realign the source */ 143 src = (const void *)i_src; 144 src -= 2; 145 break; 146 case 0x3: /* Unaligned - Off by 3 */ 147 /* Word align the source */ 148 i_src = (const void *) ((unsigned)src & ~3); 149 #ifndef __MICROBLAZEEL__ 150 /* Load the holding buffer */ 151 buf_hold = *i_src++ << 24; 152 153 for (; c >= 4; c -= 4) { 154 value = *i_src++; 155 *i_dst++ = buf_hold | value >> 8; 156 buf_hold = value << 24; 157 } 158 #else 159 /* Load the holding buffer */ 160 buf_hold = (*i_src++ & 0xFF000000) >> 24; 161 162 for (; c >= 4; c -= 4) { 163 value = *i_src++; 164 *i_dst++ = buf_hold | ((value & 0xFFFFFF) << 8); 165 buf_hold = (value & 0xFF000000) >> 24; 166 } 167 #endif 168 /* Realign the source */ 169 src = (const void *)i_src; 170 src -= 1; 171 break; 172 } 173 dst = (void *)i_dst; 174 } 175 176 /* Finish off any remaining bytes */ 177 /* simple fast copy, ... unless a cache boundary is crossed */ 178 switch (c) { 179 case 3: 180 *dst++ = *src++; 181 fallthrough; 182 case 2: 183 *dst++ = *src++; 184 fallthrough; 185 case 1: 186 *dst++ = *src++; 187 } 188 189 return v_dst; 190 } 191 #endif /* CONFIG_OPT_LIB_FUNCTION */ 192 EXPORT_SYMBOL(memcpy); 193 #endif /* __HAVE_ARCH_MEMCPY */ 194