my_string.c

基于arm7s3c2410开发板的bootloader的设计与实现源代码 采用汇编语言和C语言编写

/*
 *	my_string.c   - the base string operate
 *	
 *	Author: 	yu feng <[e-mail]>
 *	Date:		2007-5-11
 */


/*
 * int my_strlen(char *src)
 * get the length of the string src
 * input  : src  -- the pointer of the sting
 *
 */
int my_strlen(const char *src)
{
	int length;

	length = 0;

	while (src[length++] != '\0');

	return length;
}

/*
 * int my_strcmp(char *src , char *dst)
 * compare the two strings
 *
 */
int my_strcmp(const char *src , const char *dst)
{
	
	while ( *src == *dst && *dst != '\0' )
	{
		src++;
		dst++;
	}
	return (*src - *dst); 

}

/*
 * int my_strcpy(char *dst, char *src )
 * compare the two strings
 *
 */
int my_strcpy(char *dst, char *src)
{

	while (*dst++ = *src++);

	return 0;
}
/*
 * void* my_memcpy(const void *dst, void *src, int count)
 * copy one area from src to dst
 */
void* my_memcpy(const void *dst, void *src, int count)
{
	
	char *tmp = dst;
	const char *s = src;
	
	while (count--)
		*tmp++ = *s++;

	return dst;
}
/*
 * void* my_memset(void *dst, int c, int count)
 * set the dst to c from dst to dst+count
 */

void* my_memset(void *dst, int c, int count)
{
	char *xs = dst;

	while (count--)
		*xs++ = c;
	return dst;
}