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authorMichal Simek <monstr@monstr.eu>2009-03-27 14:25:21 +0100
committerMichal Simek <monstr@monstr.eu>2009-03-27 14:25:21 +0100
commit322ae8eb91c1730728400c5b8dd1108aef1205b8 (patch)
treed5c74be5b85ba2938f98172e72727b31fc214eaa /arch/microblaze/lib/memmove.c
parent16bfeaf23ead78d937b3eacfb5c7cdc7bff6d3da (diff)
downloadlinux-linaro-stable-322ae8eb91c1730728400c5b8dd1108aef1205b8.tar.gz
microblaze_v8: supported function for memory - kernel/lib
Reviewed-by: Ingo Molnar <mingo@elte.hu> Acked-by: Stephen Neuendorffer <stephen.neuendorffer@xilinx.com> Acked-by: John Linn <john.linn@xilinx.com> Acked-by: John Williams <john.williams@petalogix.com> Signed-off-by: Michal Simek <monstr@monstr.eu>
Diffstat (limited to 'arch/microblaze/lib/memmove.c')
-rw-r--r--arch/microblaze/lib/memmove.c175
1 files changed, 175 insertions, 0 deletions
diff --git a/arch/microblaze/lib/memmove.c b/arch/microblaze/lib/memmove.c
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index 000000000000..d4e9f49a71f7
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+++ b/arch/microblaze/lib/memmove.c
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+/*
+ * 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 memmove.
+ *
+ * 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, unsuccesfully, 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/types.h>
+#include <linux/stddef.h>
+#include <linux/compiler.h>
+#include <linux/module.h>
+#include <linux/string.h>
+
+#ifdef __HAVE_ARCH_MEMMOVE
+void *memmove(void *v_dst, const void *v_src, __kernel_size_t c)
+{
+ const char *src = v_src;
+ char *dst = v_dst;
+
+#ifdef CONFIG_OPT_LIB_FUNCTION
+ const uint32_t *i_src;
+ uint32_t *i_dst;
+#endif
+
+ if (!c)
+ return v_dst;
+
+ /* Use memcpy when source is higher than dest */
+ if (v_dst <= v_src)
+ return memcpy(v_dst, v_src, c);
+
+#ifndef CONFIG_OPT_LIB_FUNCTION
+ /* copy backwards, from end to beginning */
+ src += c;
+ dst += c;
+
+ /* Simple, byte oriented memmove. */
+ while (c--)
+ *--dst = *--src;
+
+ return v_dst;
+#else
+ /* 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.
+ */
+ /* FIXME this part needs more test */
+ /* Do a descending copy - this is a bit trickier! */
+ dst += c;
+ src += c;
+
+ if (c >= 4) {
+ unsigned value, buf_hold;
+
+ /* Align the destination to a word boundry. */
+ /* This is done in an endian independant manner. */
+
+ switch ((unsigned long)dst & 3) {
+ case 3:
+ *--dst = *--src;
+ --c;
+ case 2:
+ *--dst = *--src;
+ --c;
+ case 1:
+ *--dst = *--src;
+ --c;
+ }
+
+ i_dst = (void *)dst;
+ /* Choose a copy scheme based on the source */
+ /* alignment relative to dstination. */
+ 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 + 4) & ~3);
+
+ /* Load the holding buffer */
+ buf_hold = *--i_src >> 24;
+
+ for (; c >= 4; c -= 4) {
+ value = *--i_src;
+ *--i_dst = buf_hold << 8 | value;
+ buf_hold = value >> 24;
+ }
+
+ /* Realign the source */
+ src = (const void *)i_src;
+ src += 1;
+ break;
+ case 0x2: /* Unaligned - Off by 2 */
+ /* Word align the source */
+ i_src = (const void *) (((unsigned)src + 4) & ~3);
+
+ /* Load the holding buffer */
+ buf_hold = *--i_src >> 16;
+
+ for (; c >= 4; c -= 4) {
+ value = *--i_src;
+ *--i_dst = buf_hold << 16 | value;
+ buf_hold = value >> 16;
+ }
+
+ /* 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 + 4) & ~3);
+
+ /* Load the holding buffer */
+ buf_hold = *--i_src >> 8;
+
+ for (; c >= 4; c -= 4) {
+ value = *--i_src;
+ *--i_dst = buf_hold << 24 | value;
+ buf_hold = value >> 8;
+ }
+
+ /* Realign the source */
+ src = (const void *)i_src;
+ src += 3;
+ break;
+ }
+ dst = (void *)i_dst;
+ }
+
+ /* simple fast copy, ... unless a cache boundry is crossed */
+ /* Finish off any remaining bytes */
+ switch (c) {
+ case 4:
+ *--dst = *--src;
+ case 3:
+ *--dst = *--src;
+ case 2:
+ *--dst = *--src;
+ case 1:
+ *--dst = *--src;
+ }
+ return v_dst;
+#endif
+}
+EXPORT_SYMBOL(memmove);
+#endif /* __HAVE_ARCH_MEMMOVE */