Subversion Repositories HelenOS

/*
 * Copyright (c) 2001-2004 Jakub Jermar
 * Copyright (c) 2008 Jiri Svoboda
 * 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.
 */

/** @addtogroup generic 
 * @{
 */

/**
 * @file
 * @brief   Memory string operations.
 *
 * This file provides architecture independent functions to manipulate blocks of
 * memory. These functions are optimized as much as generic functions of this
 * type can be. However, architectures are free to provide even more optimized
 * versions of these functions.
 */

#include <memstr.h>
#include <arch/types.h>
#include <align.h>

/** Copy block of memory.
 *
 * Copy cnt bytes from src address to dst address.  The copying is done
 * word-by-word and then byte-by-byte.  The source and destination memory areas
 * cannot overlap.
 *
 * @param src       Source address to copy from.
 * @param dst       Destination address to copy to.
 * @param cnt       Number of bytes to copy.
 *
 * @return      Destination address.
 */
void *_memcpy(void *dst, const void *src, size_t cnt)
{
    unsigned int i, j;
    
    if (ALIGN_UP((uintptr_t) src, sizeof(unative_t)) != (uintptr_t) src ||
        ALIGN_UP((uintptr_t) dst, sizeof(unative_t)) != (uintptr_t) dst) {
        for (i = 0; i < cnt; i++)
            ((uint8_t *) dst)[i] = ((uint8_t *) src)[i];
    } else { 
        for (i = 0; i < cnt / sizeof(unative_t); i++)
            ((unative_t *) dst)[i] = ((unative_t *) src)[i];
        
        for (j = 0; j < cnt % sizeof(unative_t); j++)
            ((uint8_t *)(((unative_t *) dst) + i))[j] =
                ((uint8_t *)(((unative_t *) src) + i))[j];
    }
        
    return (char *) dst;
}

/** Move memory block with possible overlapping.
 *
 * Copy cnt bytes from src address to dst address. The source and destination
 * memory areas may overlap.
 *
 * @param src       Source address to copy from.
 * @param dst       Destination address to copy to.
 * @param cnt       Number of bytes to copy.
 *
 * @return      Destination address.
 */
void *memmove(void *dst, const void *src, size_t n)
{
    const uint8_t *sp;
    uint8_t *dp;

    /* Nothing to do? */
    if (src == dst)
        return dst;

    /* Non-overlapping? */
    if (dst >= src + n || src >= dst + n) { 
        return memcpy(dst, src, n);
    }

    /* Which direction? */
    if (src > dst) {
        /* Forwards. */
        sp = src;
        dp = dst;

        while (n-- != 0)
            *dp++ = *sp++;
    } else {
        /* Backwards. */
        sp = src + (n - 1);
        dp = dst + (n - 1);

        while (n-- != 0)
            *dp-- = *sp--;
    }

    return dst;
}

/** Fill block of memory
 *
 * Fill cnt bytes at dst address with the value x.  The filling is done
 * byte-by-byte.
 *
 * @param dst       Destination address to fill.
 * @param cnt       Number of bytes to fill.
 * @param x     Value to fill.
 *
 */
void _memsetb(void *dst, size_t cnt, uint8_t x)
{
    unsigned int i;
    uint8_t *p = (uint8_t *) dst;
    
    for (i = 0; i < cnt; i++)
        p[i] = x;
}

/** Fill block of memory.
 *
 * Fill cnt words at dst address with the value x.  The filling is done
 * word-by-word.
 *
 * @param dst       Destination address to fill.
 * @param cnt       Number of words to fill.
 * @param x     Value to fill.
 *
 */
void _memsetw(void *dst, size_t cnt, uint16_t x)
{
    unsigned int i;
    uint16_t *p = (uint16_t *) dst;
    
    for (i = 0; i < cnt; i++)
        p[i] = x;   
}

/** @}
 */