Added IPC skeleton

kernel/include/syscall.h

@@ -2,14 +2,21 @@
 #define _SYSCALL_H
 
 #include <kernel.h>
+#include <ipc.h>
 #include <isr.h>
 
-#define SYSCALL_MAX	2
-#define SYS_EXIT	0
-#define SYS_TEST	1
+#define SYSCALL_MAX	16
+enum {
+	SYS_SEND,
+	SYS_RECV,
+};
 
 int syscall_init(void);
 void syscall_register(size_t idx, void* handler);
 void syscall_handler(struct isr_int_frame* iframe);
 
+// Syscall handlers
+int sys_send(pid_t dst, ipc_msg_t* msg);
+int sys_recv(pid_t src, ipc_msg_t* msg);
+
 #endif