diff --git a/sys/SConscript b/sys/SConscript
index 9ffc3a5..633ef55 100644
--- a/sys/SConscript
+++ b/sys/SConscript
@@ -41,6 +41,7 @@ src_common = [
     "kern/palloc.c",
     "kern/printf.c",
     "kern/spinlock.c",
+    "kern/syscall.c",
     "kern/thread.c",
     "dev/ahci.c",
     "dev/console.c",
diff --git a/sys/amd64/trap.c b/sys/amd64/trap.c
index 5eafb05..346dd11 100644
--- a/sys/amd64/trap.c
+++ b/sys/amd64/trap.c
@@ -7,6 +7,7 @@
 #include <sys/kdebug.h>
 #include <sys/spinlock.h>
 #include <sys/irq.h>
+#include <sys/syscall.h>
 
 #include <machine/amd64.h>
 #include <machine/lapic.h>
@@ -147,7 +148,8 @@ trap_entry(TrapFrame *tf)
 	    Debug_Breakpoint(tf);
 	    return;
 	case T_SYSCALL:
-	    kprintf("Userlevel syscall\n");
+	    kprintf("Syscall %016llx\n", tf->rdi);
+	    tf->rax = Syscall_Entry(tf->rdi, tf->rsi, tf->rdx, tf->rcx, tf->r8, tf->r9);
 	    return;
 	default:
 	    return;
diff --git a/sys/include/syscall.h b/sys/include/syscall.h
new file mode 100644
index 0000000..28af8d9
--- /dev/null
+++ b/sys/include/syscall.h
@@ -0,0 +1,44 @@
+
+#ifndef __SYS_SYSCALL_H__
+#define __SYS_SYSCALL_H__
+
+#define SYSCALL_NULL		0x00
+#define SYSCALL_TIME		0x01
+#define SYSCALL_EXIT		0x02
+#define SYSCALL_SPAWN		0x03
+#define SYSCALL_GETPID		0x04
+
+// Memory
+#define SYSCALL_MMAP		0x08
+#define SYSCALL_MUNMAP		0x09
+#define SYSCALL_MPROTECT	0x0A
+
+// Stream
+#define SYSCALL_READ		0x10
+#define SYSCALL_WRITE		0x11
+#define SYSCALL_FLUSH		0x12
+
+// File
+#define SYSCALL_OPEN		0x18
+#define SYSCALL_CLOSE		0x19
+#define SYSCALL_MOVE		0x1A
+#define SYSCALL_DELETE		0x1B
+#define SYSCALL_SETLENGTH	0x1C
+
+// Threading
+#define SYSCALL_THREADCREATE	0x30
+#define SYSCALL_THREADEXIT	0x31
+#define SYSCALL_THREADSLEEP	0x32
+
+// Network
+#define SYSCALL_SOCKET		0x40
+#define SYSCALL_BIND		0x41
+#define SYSCALL_CONNECT		0x42
+#define SYSCALL_LISTEN		0x43
+#define SYSCALL_SHUTDOWN	0x44
+
+uint64_t Syscall_Entry(uint64_t syscall, uint64_t a1, uint64_t a2,
+		       uint64_t a3, uint64_t a4, uint64_t a5);
+
+#endif /* __SYS_SYSCALL_H__ */
+
diff --git a/sys/kern/syscall.c b/sys/kern/syscall.c
new file mode 100644
index 0000000..9e400c7
--- /dev/null
+++ b/sys/kern/syscall.c
@@ -0,0 +1,97 @@
+
+#include <stdbool.h>
+#include <stdint.h>
+
+#include <sys/kassert.h>
+#include <sys/syscall.h>
+
+uint64_t
+Syscall_Time()
+{
+    NOT_IMPLEMENTED();
+    return 0;
+}
+
+uint64_t
+Syscall_Exit(uint64_t status)
+{
+    NOT_IMPLEMENTED();
+    return 0;
+}
+
+uint64_t
+Syscall_Spawn(uint64_t path)
+{
+    NOT_IMPLEMENTED();
+    return 0;
+}
+
+uint64_t
+Syscall_GetPID()
+{
+    NOT_IMPLEMENTED();
+    return 0;
+}
+
+uint64_t
+Syscall_MMap(uint64_t addr, uint64_t len, uint64_t prot)
+{
+    NOT_IMPLEMENTED();
+    return 0;
+}
+
+uint64_t
+Syscall_MUnmap(uint64_t addr, uint64_t len)
+{
+    NOT_IMPLEMENTED();
+    return 0;
+}
+
+uint64_t
+Syscall_MProtect(uint64_t addr, uint64_t len, uint64_t prot)
+{
+    NOT_IMPLEMENTED();
+    return 0;
+}
+
+uint64_t
+Syscall_Read(uint64_t fd, uint64_t addr, uint64_t length)
+{
+    NOT_IMPLEMENTED();
+    return 0;
+}
+
+uint64_t
+Syscall_Write(uint64_t fd, uint64_t addr, uint64_t length)
+{
+    NOT_IMPLEMENTED();
+    return 0;
+}
+
+uint64_t
+Syscall_Entry(uint64_t syscall, uint64_t a1, uint64_t a2,
+	      uint64_t a3, uint64_t a4, uint64_t a5)
+{
+    switch (syscall)
+    {
+	case SYSCALL_NULL:
+	    return 0;
+	case SYSCALL_TIME:
+	    return Syscall_Time();
+	case SYSCALL_EXIT:
+	    return Syscall_Exit(a1);
+	case SYSCALL_MMAP:
+	    return Syscall_MMap(a1, a2, a3);
+	case SYSCALL_MUNMAP:
+	    return Syscall_MUnmap(a1, a2);
+	case SYSCALL_MPROTECT:
+	    return Syscall_MProtect(a1, a2, a3);
+	case SYSCALL_READ:
+	    return Syscall_Read(a1, a2, a3);
+	case SYSCALL_WRITE:
+	    return Syscall_Write(a1, a2, a3);
+	default:
+	    return (uint64_t)-1;
+    }
+}
+