acrn-hypervisor/hypervisor/lib/memset.c

60 lines
2.1 KiB
C

/*
* Copyright (C) 2018 Intel Corporation. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Intel Corporation nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <rtl.h>
#include <util.h>
#include <macros.h>
void *memset(void *base, uint8_t v, size_t n)
{
uint8_t *dest_p;
size_t n_q;
size_t count;
dest_p = (uint8_t *)base;
if ((dest_p == NULL) || (n == 0))
return NULL;
/*do the few bytes to get uint64_t alignment*/
count = n;
for (; count && ((uint64_t)dest_p & 7); count--)
*dest_p++ = v;
/*64-bit mode*/
n_q = count >> 3;
asm volatile("cld ; rep ; stosq ; movl %3,%%ecx ; rep ; stosb"
: "+c"(n_q), "+D"(dest_p)
: "a" (v * 0x0101010101010101U),
"r"((unsigned int)count & 7));
return (void *)dest_p;
}