mirror of https://gitee.com/openkylin/linux.git
104 lines
1.8 KiB
C
104 lines
1.8 KiB
C
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/*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file COPYING in the main directory of this archive
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* for more details.
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*/
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#include <linux/module.h>
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#include <linux/string.h>
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void *memmove(void *dest, const void *src, size_t n)
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{
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void *xdest = dest;
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size_t temp;
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if (!n)
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return xdest;
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if (dest < src) {
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if ((long)dest & 1) {
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char *cdest = dest;
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const char *csrc = src;
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*cdest++ = *csrc++;
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dest = cdest;
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src = csrc;
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n--;
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}
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if (n > 2 && (long)dest & 2) {
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short *sdest = dest;
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const short *ssrc = src;
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*sdest++ = *ssrc++;
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dest = sdest;
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src = ssrc;
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n -= 2;
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}
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temp = n >> 2;
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if (temp) {
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long *ldest = dest;
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const long *lsrc = src;
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temp--;
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do
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*ldest++ = *lsrc++;
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while (temp--);
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dest = ldest;
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src = lsrc;
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}
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if (n & 2) {
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short *sdest = dest;
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const short *ssrc = src;
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*sdest++ = *ssrc++;
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dest = sdest;
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src = ssrc;
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}
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if (n & 1) {
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char *cdest = dest;
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const char *csrc = src;
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*cdest = *csrc;
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}
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} else {
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dest = (char *)dest + n;
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src = (const char *)src + n;
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if ((long)dest & 1) {
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char *cdest = dest;
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const char *csrc = src;
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*--cdest = *--csrc;
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dest = cdest;
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src = csrc;
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n--;
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}
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if (n > 2 && (long)dest & 2) {
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short *sdest = dest;
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const short *ssrc = src;
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*--sdest = *--ssrc;
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dest = sdest;
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src = ssrc;
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n -= 2;
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}
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temp = n >> 2;
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if (temp) {
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long *ldest = dest;
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const long *lsrc = src;
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temp--;
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do
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*--ldest = *--lsrc;
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while (temp--);
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dest = ldest;
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src = lsrc;
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}
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if (n & 2) {
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short *sdest = dest;
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const short *ssrc = src;
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*--sdest = *--ssrc;
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dest = sdest;
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src = ssrc;
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}
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if (n & 1) {
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char *cdest = dest;
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const char *csrc = src;
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*--cdest = *--csrc;
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}
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}
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return xdest;
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}
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EXPORT_SYMBOL(memmove);
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