klib.c

来自「这是《自己动手写操作系统》的原文件和代码」· C语言 代码 · 共 61 行

/*++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
                            klib.c
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
                                                    Forrest Yu, 2005
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*/

#include "type.h"
#include "const.h"
#include "protect.h"
#include "proto.h"
#include "string.h"
#include "global.h"


/*======================================================================*
                               itoa
 *======================================================================*/
PUBLIC char * itoa(char * str, int num)/* 数字前面的 0 不被显示出来, 比如 0000B800 被显示成 B800 */
{
	char *	p = str;
	char	ch;
	int	i;
	t_bool	flag = FALSE;

	*p++ = '0';
	*p++ = 'x';

	if(num == 0){
		*p++ = '0';
	}
	else{	
		for(i=28;i>=0;i-=4){
			ch = (num >> i) & 0xF;
			if(flag || (ch > 0)){
				flag = TRUE;
				ch += '0';
				if(ch > '9'){
					ch += 7;
				}
				*p++ = ch;
			}
		}
	}

	*p = 0;

	return str;
}


/*======================================================================*
                               disp_int
 *======================================================================*/
PUBLIC void disp_int(int input)
{
	char output[16];
	itoa(output, input);
	disp_str(output);
}