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Diffstat (limited to 'arch/microblaze/lib/memcpy.c')
| -rw-r--r-- | arch/microblaze/lib/memcpy.c | 189 |
1 files changed, 189 insertions, 0 deletions
diff --git a/arch/microblaze/lib/memcpy.c b/arch/microblaze/lib/memcpy.c new file mode 100644 index 000000000..f536e81b8 --- /dev/null +++ b/arch/microblaze/lib/memcpy.c @@ -0,0 +1,189 @@ +/* + * Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu> + * Copyright (C) 2008-2009 PetaLogix + * Copyright (C) 2007 John Williams + * + * Reasonably optimised generic C-code for memcpy on Microblaze + * This is generic C code to do efficient, alignment-aware memcpy. + * + * It is based on demo code originally Copyright 2001 by Intel Corp, taken from + * http://www.embedded.com/showArticle.jhtml?articleID=19205567 + * + * Attempts were made, unsuccessfully, to contact the original + * author of this code (Michael Morrow, Intel). Below is the original + * copyright notice. + * + * This software has been developed by Intel Corporation. + * Intel specifically disclaims all warranties, express or + * implied, and all liability, including consequential and + * other indirect damages, for the use of this program, including + * liability for infringement of any proprietary rights, + * and including the warranties of merchantability and fitness + * for a particular purpose. Intel does not assume any + * responsibility for and errors which may appear in this program + * not any responsibility to update it. + */ + +#include <linux/export.h> +#include <linux/types.h> +#include <linux/stddef.h> +#include <linux/compiler.h> + +#include <linux/string.h> + +#ifdef __HAVE_ARCH_MEMCPY +#ifndef CONFIG_OPT_LIB_FUNCTION +void *memcpy(void *v_dst, const void *v_src, __kernel_size_t c) +{ + const char *src = v_src; + char *dst = v_dst; + + /* Simple, byte oriented memcpy. */ + while (c--) + *dst++ = *src++; + + return v_dst; +} +#else /* CONFIG_OPT_LIB_FUNCTION */ +void *memcpy(void *v_dst, const void *v_src, __kernel_size_t c) +{ + const char *src = v_src; + char *dst = v_dst; + + /* The following code tries to optimize the copy by using unsigned + * alignment. This will work fine if both source and destination are + * aligned on the same boundary. However, if they are aligned on + * different boundaries shifts will be necessary. This might result in + * bad performance on MicroBlaze systems without a barrel shifter. + */ + const uint32_t *i_src; + uint32_t *i_dst; + + if (likely(c >= 4)) { + unsigned value, buf_hold; + + /* Align the destination to a word boundary. */ + /* This is done in an endian independent manner. */ + switch ((unsigned long)dst & 3) { + case 1: + *dst++ = *src++; + --c; + case 2: + *dst++ = *src++; + --c; + case 3: + *dst++ = *src++; + --c; + } + + i_dst = (void *)dst; + + /* Choose a copy scheme based on the source */ + /* alignment relative to destination. */ + switch ((unsigned long)src & 3) { + case 0x0: /* Both byte offsets are aligned */ + i_src = (const void *)src; + + for (; c >= 4; c -= 4) + *i_dst++ = *i_src++; + + src = (const void *)i_src; + break; + case 0x1: /* Unaligned - Off by 1 */ + /* Word align the source */ + i_src = (const void *) ((unsigned)src & ~3); +#ifndef __MICROBLAZEEL__ + /* Load the holding buffer */ + buf_hold = *i_src++ << 8; + + for (; c >= 4; c -= 4) { + value = *i_src++; + *i_dst++ = buf_hold | value >> 24; + buf_hold = value << 8; + } +#else + /* Load the holding buffer */ + buf_hold = (*i_src++ & 0xFFFFFF00) >> 8; + + for (; c >= 4; c -= 4) { + value = *i_src++; + *i_dst++ = buf_hold | ((value & 0xFF) << 24); + buf_hold = (value & 0xFFFFFF00) >> 8; + } +#endif + /* Realign the source */ + src = (const void *)i_src; + src -= 3; + break; + case 0x2: /* Unaligned - Off by 2 */ + /* Word align the source */ + i_src = (const void *) ((unsigned)src & ~3); +#ifndef __MICROBLAZEEL__ + /* Load the holding buffer */ + buf_hold = *i_src++ << 16; + + for (; c >= 4; c -= 4) { + value = *i_src++; + *i_dst++ = buf_hold | value >> 16; + buf_hold = value << 16; + } +#else + /* Load the holding buffer */ + buf_hold = (*i_src++ & 0xFFFF0000) >> 16; + + for (; c >= 4; c -= 4) { + value = *i_src++; + *i_dst++ = buf_hold | ((value & 0xFFFF) << 16); + buf_hold = (value & 0xFFFF0000) >> 16; + } +#endif + /* Realign the source */ + src = (const void *)i_src; + src -= 2; + break; + case 0x3: /* Unaligned - Off by 3 */ + /* Word align the source */ + i_src = (const void *) ((unsigned)src & ~3); +#ifndef __MICROBLAZEEL__ + /* Load the holding buffer */ + buf_hold = *i_src++ << 24; + + for (; c >= 4; c -= 4) { + value = *i_src++; + *i_dst++ = buf_hold | value >> 8; + buf_hold = value << 24; + } +#else + /* Load the holding buffer */ + buf_hold = (*i_src++ & 0xFF000000) >> 24; + + for (; c >= 4; c -= 4) { + value = *i_src++; + *i_dst++ = buf_hold | ((value & 0xFFFFFF) << 8); + buf_hold = (value & 0xFF000000) >> 24; + } +#endif + /* Realign the source */ + src = (const void *)i_src; + src -= 1; + break; + } + dst = (void *)i_dst; + } + + /* Finish off any remaining bytes */ + /* simple fast copy, ... unless a cache boundary is crossed */ + switch (c) { + case 3: + *dst++ = *src++; + case 2: + *dst++ = *src++; + case 1: + *dst++ = *src++; + } + + return v_dst; +} +#endif /* CONFIG_OPT_LIB_FUNCTION */ +EXPORT_SYMBOL(memcpy); +#endif /* __HAVE_ARCH_MEMCPY */ |