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/* Taken from newlib... */
#include <cstring>
#include <cstddef>
#include <climits>
/* Nonzero if either X or Y is not aligned on a "long" boundary. */
#define UNALIGNED(X, Y) \
(((long)X & (sizeof (long) - 1)) | ((long)Y & (sizeof (long) - 1)))
/* How many bytes are copied each iteration of the 4X unrolled loop. */
#define BIGBLOCKSIZE (sizeof (long) << 2)
/* How many bytes are copied each iteration of the word copy loop. */
#define LITTLEBLOCKSIZE (sizeof (long))
/* Threshhold for punting to the byte copier. */
#define TOO_SMALL(LEN) ((LEN) < BIGBLOCKSIZE)
extern "C"
void *memmove (void *dst_void, const void *src_void, size_t length)
{
char *dst = reinterpret_cast<char *>(dst_void);
const char *src = reinterpret_cast<const char *>(src_void);
long *aligned_dst;
const long *aligned_src;
if (src < dst && dst < src + length)
{
/* Destructive overlap...have to copy backwards */
src += length;
dst += length;
while (length--)
{
*--dst = *--src;
}
}
else
{
/* Use optimizing algorithm for a non-destructive copy to closely
match memcpy. If the size is small or either SRC or DST is unaligned,
then punt into the byte copy loop. This should be rare. */
if (!TOO_SMALL(length) && !UNALIGNED (src, dst))
{
aligned_dst = (long*)dst;
aligned_src = (long*)src;
/* Copy 4X long words at a time if possible. */
while (length >= BIGBLOCKSIZE)
{
*aligned_dst++ = *aligned_src++;
*aligned_dst++ = *aligned_src++;
*aligned_dst++ = *aligned_src++;
*aligned_dst++ = *aligned_src++;
length -= BIGBLOCKSIZE;
}
/* Copy one long word at a time if possible. */
while (length >= LITTLEBLOCKSIZE)
{
*aligned_dst++ = *aligned_src++;
length -= LITTLEBLOCKSIZE;
}
/* Pick up any residual with a byte copier. */
dst = (char*)aligned_dst;
src = (char*)aligned_src;
}
while (length--)
{
*dst++ = *src++;
}
}
return dst_void;
}
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