update lab1-8 codes and docs. now version is 0.2

code/lab8/user/libs/syscall.c

@@ -84,7 +84,7 @@ sys_sleep(unsigned int time) {
     return syscall(SYS_sleep, time);
 }
 
-size_t
+int
 sys_gettime(void) {
     return syscall(SYS_gettime);
 }

code/lab8/user/libs/syscall.h

@@ -11,7 +11,7 @@ int sys_getpid(void);
 int sys_putc(int c);
 int sys_pgdir(void);
 int sys_sleep(unsigned int time);
-size_t sys_gettime(void);
+int sys_gettime(void);
 
 struct stat;
 struct dirent;