add exercise of lab5 spoc discussion

related_info/lab5/lab5-spoc-discuss/libs/unistd.h

@@ -0,0 +1,29 @@
+#ifndef __LIBS_UNISTD_H__
+#define __LIBS_UNISTD_H__
+
+#define T_SYSCALL           0x80
+
+/* syscall number */
+#define SYS_exit            1
+#define SYS_fork            2
+#define SYS_wait            3
+#define SYS_exec            4
+#define SYS_clone           5
+#define SYS_yield           10
+#define SYS_sleep           11
+#define SYS_kill            12
+#define SYS_gettime         17
+#define SYS_getpid          18
+#define SYS_brk             19
+#define SYS_mmap            20
+#define SYS_munmap          21
+#define SYS_shmem           22
+#define SYS_putc            30
+#define SYS_pgdir           31
+
+/* SYS_fork flags */
+#define CLONE_VM            0x00000100  // set if VM shared between processes
+#define CLONE_THREAD        0x00000200  // thread group
+
+#endif /* !__LIBS_UNISTD_H__ */
+