1. 根目录:
2. arch
3. powerpc
4. xmon
5. nonstdio.h

#define EOF	(-1)

#define printf	xmon_printf
#define putchar	xmon_putchar

extern int xmon_putchar(int c);
extern void xmon_puts(const char *);
extern char *xmon_gets(char *, int);
extern void xmon_printf(const char *, ...);