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/*

 * Copyright (C) 2005 Sergey Bondari

 * 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.

 * - The name of the author may not be used to endorse or promote products

 *   derived from this software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.

 */

#ifndef __ia32_MEMSTR_H__

#define __ia32_MEMSTR_H__

/** Copy memory

 *

 * Copy a given number of bytes (3rd argument)

 * from the memory location defined by 2nd argument

 * to the memory location defined by 1st argument.

 * The memory areas cannot overlap.

 *

 * @param dst Destination

 * @param src Source

 * @param cnt Number of bytes

 * @return Destination

 */

static inline void * memcpy(void * dst, const void * src, size_t cnt)

{

        __native d0, d1, d2;

        __asm__ __volatile__(

                /* copy all full dwords */

                "rep movsl\n\t"

                /* load count again */

                "movl %4, %%ecx\n\t"

                /* ecx = ecx mod 4 */

                "andl $3, %%ecx\n\t"

                /* are there last <=3 bytes? */

                "jz 1f\n\t"

                /* copy last <=3 bytes */

                "rep movsb\n\t"

                /* exit from asm block */

                "1:\n"

                : "=&c" (d0), "=&D" (d1), "=&S" (d2)

                : "0" ((__native) (cnt / 4)), "g" ((__native) cnt), "1" ((__native) dst), "2" ((__native) src)

                : "memory");

        return dst;

}

/** Compare memory regions for equality

 *

 * Compare a given number of bytes (3rd argument)

 * at memory locations defined by 1st and 2nd argument

 * for equality. If bytes are equal function returns 0.

 *

 * @param src Region 1

 * @param dst Region 2

 * @param cnt Number of bytes

 * @return Zero if bytes are equal, non-zero otherwise

 */

static inline int memcmp(const void * src, const void * dst, size_t cnt)

{

    __u32 d0, d1, d2;

    int ret;

    __asm__ (

        "repe cmpsb\n\t"

        "je 1f\n\t"

        "movl %3, %0\n\t"

        "addl $1, %0\n\t"

        "1:\n"

        : "=a" (ret), "=%S" (d0), "=&D" (d1), "=&c" (d2)

        : "0" (0), "1" ((__native) src), "2" ((__native) dst), "3" ((__native) cnt)

    );

    return ret;

}

/** Fill memory with words

 * Fill a given number of words (2nd argument)

 * at memory defined by 1st argument with the

 * word value defined by 3rd argument.

 *

 * @param dst Destination

 * @param cnt Number of words

 * @param x Value to fill

 */

static inline void memsetw(__address dst, size_t cnt, __u16 x)

{

    __u32 d0, d1;

    __asm__ __volatile__ (

        "rep stosw\n\t"

        : "=&D" (d0), "=&c" (d1), "=a" (x)

        : "0" (dst), "1" (cnt), "2" (x)

        : "memory"

    );

}

/** Fill memory with bytes

 * Fill a given number of bytes (2nd argument)

 * at memory defined by 1st argument with the

 * word value defined by 3rd argument.

 *

 * @param dst Destination

 * @param cnt Number of bytes

 * @param x Value to fill

 */

static inline void memsetb(__address dst, size_t cnt, __u8 x)

{

    __u32 d0, d1;

    __asm__ __volatile__ (

        "rep stosb\n\t"

        : "=&D" (d0), "=&c" (d1), "=a" (x)

        : "0" (dst), "1" (cnt), "2" (x)

        : "memory"

    );

}

#endif