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913d38ba14
PMP configurations for load and store addresses may have different permissions (e.g., "R" vs. "RW"). Due to the timing alignment of internal signals, the address permission check may be incorrectly applied during the second part of a misaligned access transaction. As a workaround, insert two instructions (e.g. ADDI/NOP) between accessing to different memory regions. This spacing avoids the false permission check caused by signal timing overlap.
59 lines
1.4 KiB
C
59 lines
1.4 KiB
C
/*
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* SPDX-FileCopyrightText: 1994-2009 Red Hat, Inc.
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*
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* SPDX-License-Identifier: BSD-2-Clause-FreeBSD AND Apache-2.0
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*
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* SPDX-FileContributor: 2025 Espressif Systems (Shanghai) CO LTD
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*/
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#include <string.h>
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#include "string/local.h"
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int
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memcmp(const void *m1,
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const void *m2,
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size_t n)
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{
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unsigned char *s1 = (unsigned char *) m1;
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unsigned char *s2 = (unsigned char *) m2;
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unsigned long *a1;
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unsigned long *a2;
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/* If the size is too small, or either pointer is unaligned,
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then we punt to the byte compare loop. Hopefully this will
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not turn up in inner loops. */
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if (!TOO_SMALL_LITTLE_BLOCK(n) && !UNALIGNED_X_Y(s1, s2)) {
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/* Otherwise, load and compare the blocks of memory one
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word at a time. */
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a1 = (unsigned long*) s1;
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a2 = (unsigned long*) s2;
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while (!TOO_SMALL_LITTLE_BLOCK(n)) {
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if (*a1 != *a2) {
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break;
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}
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a1++;
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a2++;
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n -= LITTLE_BLOCK_SIZE;
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}
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/* check m mod LITTLE_BLOCK_SIZE remaining characters */
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s1 = (unsigned char*)a1;
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s2 = (unsigned char*)a2;
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}
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while (n--) {
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if (*s1 != *s2) {
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return *s1 - *s2;
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}
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s1++;
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s2++;
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}
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return 0;
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}
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// Hook to force the linker to include this file
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void esp_libc_include_memcmp_impl(void)
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{
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}
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