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Per C11 standard (ISO/IEC 9899:2011): K.3.7.1.1 1. Copying shall not take place between objects that overlap; 2. If there is a runtime-constraint violation, the memcpy_s function stores zeros in the first s1max characters of the object; 3. The memcpy_s function returns zero if there was no runtime-constraint violation. Otherwise, a nonzero value is returned. Tracked-On: #4885 Signed-off-by: Victor Sun <victor.sun@intel.com> Reviewed-by: Yonghua Huang <yonghua.huang@intel.com> Reviewed-by: Yin Fengwei <fengwei.yin@intel.com> Acked-by: Eddie Dong <eddie.dong@intel.com>
62 lines
1.3 KiB
C
62 lines
1.3 KiB
C
/*
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* Copyright (C) 2018 Intel Corporation.
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* SPDX-License-Identifier: BSD-3-Clause
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*/
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#include <types.h>
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static inline void memset_erms(void *base, uint8_t v, size_t n)
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{
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asm volatile("rep ; stosb"
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: "+D"(base)
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: "a" (v), "c"(n));
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}
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void *memset(void *base, uint8_t v, size_t n)
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{
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/*
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* Some CPUs support enhanced REP MOVSB/STOSB feature. It is recommended
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* to use it when possible.
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*/
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if ((base != NULL) && (n != 0U)) {
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memset_erms(base, v, n);
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}
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return base;
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}
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static inline void memcpy_erms(void *d, const void *s, size_t slen)
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{
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asm volatile ("rep; movsb"
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: "=&D"(d), "=&S"(s)
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: "c"(slen), "0" (d), "1" (s)
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: "memory");
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}
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/*
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* @brief Copies at most slen bytes from src address to dest address, up to dmax.
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*
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* INPUTS
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*
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* @param[in] d pointer to Destination address
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* @param[in] dmax maximum length of dest
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* @param[in] s pointer to Source address
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* @param[in] slen maximum number of bytes of src to copy
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*
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* @return 0 for success and -1 for runtime-constraint violation.
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*/
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int32_t memcpy_s(void *d, size_t dmax, const void *s, size_t slen)
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{
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int32_t ret = -1;
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if ((d != NULL) && (s != NULL) && (dmax >= slen) && ((d > (s + slen)) || (s > (d + dmax)))) {
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if (slen != 0U) {
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memcpy_erms(d, s, slen);
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}
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ret = 0;
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} else {
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(void)memset(d, 0U, dmax);
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}
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return ret;
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}
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