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borysp
3014a0dd1c
Mostly adds missing "memory" clobber which caused some nasty bugs - gcc optimized those inline asms and assumed values returned by them never change.
25 lines
828 B
C
25 lines
828 B
C
/* SPDX-License-Identifier: LGPL-3.0-or-later */
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/* Copyright (C) 2020 Invisible Things Lab
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* Michał Kowalczyk <mkow@invisiblethingslab.com>
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*/
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#include <stdint.h>
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#include "api.h"
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void* memset(void* dest, int ch, size_t count) {
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char* d = dest;
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#if defined(__x86_64__)
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/* "Beginning with processors based on Intel microarchitecture code name Ivy Bridge, REP string
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* operation using MOVSB and STOSB can provide both flexible and high-performance REP string
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* operations for software in common situations like memory copy and set operations"
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* Intel 64 and IA-32 Architectures Optimization Reference Manual
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*/
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__asm__ volatile("rep stosb" : "+D"(d), "+c"(count) : "a"((uint8_t)ch) : "cc", "memory");
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#else
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while (count--)
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*d++ = ch;
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#endif
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return dest;
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}
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