73 строки
1.5 KiB
C
73 строки
1.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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#include <linux/types.h>
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#include <asm/string.h>
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#define OPSIZ (BITS_PER_LONG/8)
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typedef unsigned long op_t;
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void *
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memset (void *dstpp, int sc, size_t len)
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{
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unsigned int c = sc;
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long int dstp = (long int) dstpp;
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if (len >= 8)
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{
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size_t xlen;
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op_t cccc;
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cccc = (unsigned char) c;
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cccc |= cccc << 8;
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cccc |= cccc << 16;
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if (OPSIZ > 4)
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/* Do the shift in two steps to avoid warning if long has 32 bits. */
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cccc |= (cccc << 16) << 16;
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/* There are at least some bytes to set.
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No need to test for LEN == 0 in this alignment loop. */
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while (dstp % OPSIZ != 0)
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{
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((unsigned char *) dstp)[0] = c;
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dstp += 1;
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len -= 1;
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}
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/* Write 8 `op_t' per iteration until less than 8 `op_t' remain. */
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xlen = len / (OPSIZ * 8);
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while (xlen > 0)
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{
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((op_t *) dstp)[0] = cccc;
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((op_t *) dstp)[1] = cccc;
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((op_t *) dstp)[2] = cccc;
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((op_t *) dstp)[3] = cccc;
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((op_t *) dstp)[4] = cccc;
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((op_t *) dstp)[5] = cccc;
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((op_t *) dstp)[6] = cccc;
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((op_t *) dstp)[7] = cccc;
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dstp += 8 * OPSIZ;
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xlen -= 1;
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}
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len %= OPSIZ * 8;
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/* Write 1 `op_t' per iteration until less than OPSIZ bytes remain. */
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xlen = len / OPSIZ;
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while (xlen > 0)
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{
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((op_t *) dstp)[0] = cccc;
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dstp += OPSIZ;
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xlen -= 1;
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}
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len %= OPSIZ;
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}
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/* Write the last few bytes. */
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while (len > 0)
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{
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((unsigned char *) dstp)[0] = c;
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dstp += 1;
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len -= 1;
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}
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return dstpp;
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}
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