LAB 4 IS DONE.

lab/inc/syscall.h

@@ -0,0 +1,22 @@
+#ifndef JOS_INC_SYSCALL_H
+#define JOS_INC_SYSCALL_H
+
+/* system call numbers */
+enum {
+	SYS_cputs = 0,
+	SYS_cgetc,
+	SYS_getenvid,
+	SYS_env_destroy,
+	SYS_page_alloc,
+	SYS_page_map,
+	SYS_page_unmap,
+	SYS_exofork,
+	SYS_env_set_status,
+	SYS_env_set_pgfault_upcall,
+	SYS_yield,
+	SYS_ipc_try_send,
+	SYS_ipc_recv,
+	NSYSCALLS
+};
+
+#endif /* !JOS_INC_SYSCALL_H */