diff --git a/zion/CMakeLists.txt b/zion/CMakeLists.txt
index 9b959d2..abf387a 100644
--- a/zion/CMakeLists.txt
+++ b/zion/CMakeLists.txt
@@ -28,7 +28,9 @@ add_executable(zion
   scheduler/process_manager.cpp
   scheduler/scheduler.cpp
   syscall/address_space.cpp
+  syscall/capability.cpp
   syscall/channel.cpp
+  syscall/debug.cpp
   syscall/memory_object.cpp
   syscall/port.cpp
   syscall/process.cpp
diff --git a/zion/include/zcall.h b/zion/include/zcall.h
index d5c07de..16e7452 100644
--- a/zion/include/zcall.h
+++ b/zion/include/zcall.h
@@ -123,6 +123,6 @@ SYS5(PortPoll, z_cap_t, port_cap, uint64_t*, num_bytes, void*, data, uint64_t*,
 
 SYS2(IrqRegister, uint64_t, irq_num, z_cap_t*, port_cap);
 
-[[nodiscard]] z_err_t ZCapDuplicate(z_cap_t cap_in, z_cap_t* cap_out);
+SYS2(CapDuplicate, z_cap_t, cap_in, z_cap_t*, cap_out);
 
-[[nodiscard]] z_err_t ZDebug(const char* message);
+SYS1(Debug, const char*, message);
diff --git a/zion/include/ztypes.h b/zion/include/ztypes.h
index 3d73768..cb1ed95 100644
--- a/zion/include/ztypes.h
+++ b/zion/include/ztypes.h
@@ -64,10 +64,10 @@ const uint64_t kZionIrqRegister = 0x58;
 #define Z_IRQ_PCI_BASE 0x30
 
 // Capability Calls
-#define Z_CAP_DUPLICATE 0x60
+const uint64_t kZionCapDuplicate = 0x70;
 
 // Debugging Calls.
-#define Z_DEBUG_PRINT 0x10000000
+const uint64_t kZionDebug = 0x1'0000;
 
 /* ------------------------------
  * Capability Types
diff --git a/zion/syscall/capability.cpp b/zion/syscall/capability.cpp
new file mode 100644
index 0000000..4953c14
--- /dev/null
+++ b/zion/syscall/capability.cpp
@@ -0,0 +1,13 @@
+#include "syscall/capability.h"
+
+#include "scheduler/scheduler.h"
+
+z_err_t CapDuplicate(ZCapDuplicateReq* req) {
+  auto& proc = gScheduler->CurrentProcess();
+  auto cap = proc.GetCapability(req->cap_in);
+  if (!cap) {
+    return Z_ERR_CAP_NOT_FOUND;
+  }
+  *req->cap_out = proc.AddExistingCapability(cap);
+  return Z_OK;
+}
diff --git a/zion/syscall/capability.h b/zion/syscall/capability.h
new file mode 100644
index 0000000..07ee631
--- /dev/null
+++ b/zion/syscall/capability.h
@@ -0,0 +1,5 @@
+#pragma once
+
+#include "include/zcall.h"
+
+z_err_t CapDuplicate(ZCapDuplicateReq* req);
diff --git a/zion/syscall/debug.cpp b/zion/syscall/debug.cpp
new file mode 100644
index 0000000..45989ab
--- /dev/null
+++ b/zion/syscall/debug.cpp
@@ -0,0 +1,8 @@
+#include "syscall/debug.h"
+
+#include "debug/debug.h"
+
+z_err_t Debug(ZDebugReq* req) {
+  dbgln("[Debug] %s", req->message);
+  return Z_OK;
+}
diff --git a/zion/syscall/debug.h b/zion/syscall/debug.h
new file mode 100644
index 0000000..0b4aa06
--- /dev/null
+++ b/zion/syscall/debug.h
@@ -0,0 +1,5 @@
+#pragma once
+
+#include "include/zcall.h"
+
+z_err_t Debug(ZDebugReq* req);
diff --git a/zion/syscall/syscall.cpp b/zion/syscall/syscall.cpp
index b093113..f069f2a 100644
--- a/zion/syscall/syscall.cpp
+++ b/zion/syscall/syscall.cpp
@@ -13,7 +13,9 @@
 #include "scheduler/process_manager.h"
 #include "scheduler/scheduler.h"
 #include "syscall/address_space.h"
+#include "syscall/capability.h"
 #include "syscall/channel.h"
+#include "syscall/debug.h"
 #include "syscall/memory_object.h"
 #include "syscall/port.h"
 #include "syscall/process.h"
@@ -63,16 +65,6 @@ z_err_t ValidateCap(const RefPtr<Capability>& cap, uint64_t permissions) {
   return Z_OK;
 }
 
-z_err_t CapDuplicate(ZCapDuplicateReq* req, ZCapDuplicateResp* resp) {
-  auto& proc = gScheduler->CurrentProcess();
-  auto cap = proc.GetCapability(req->cap);
-  if (!cap) {
-    return Z_ERR_CAP_NOT_FOUND;
-  }
-  resp->cap = proc.AddExistingCapability(cap);
-  return Z_OK;
-}
-
 #define CASE(name)  \
   case kZion##name: \
     return name(reinterpret_cast<Z##name##Req*>(req));
@@ -104,13 +96,10 @@ extern "C" z_err_t SyscallHandler(uint64_t call_id, void* req, void* resp) {
     CASE(PortRecv);
     CASE(PortPoll);
     CASE(IrqRegister);
-    case Z_CAP_DUPLICATE:
-      return CapDuplicate(reinterpret_cast<ZCapDuplicateReq*>(req),
-                          reinterpret_cast<ZCapDuplicateResp*>(resp));
-    case Z_DEBUG_PRINT:
-      dbgln("[Debug] %s", req);
-      return Z_OK;
-      break;
+    // syscall/capability.h
+    CASE(CapDuplicate);
+    // syscall/debug.h
+    CASE(Debug);
     default:
       panic("Unhandled syscall number: %x", call_id);
   }
diff --git a/zion/usr/zcall.cpp b/zion/usr/zcall.cpp
index f754da1..34d9025 100644
--- a/zion/usr/zcall.cpp
+++ b/zion/usr/zcall.cpp
@@ -4,29 +4,8 @@
 
 #include "usr/zcall_internal.h"
 
-z_err_t SysCall2(uint64_t number, const void* first, const void* second) {
+z_err_t SysCall1(uint64_t number, const void* first) {
   z_err_t return_code;
-  asm("syscall"
-      : "=a"(return_code)
-      : "D"(number), "S"(first), "d"(second)
-      : "rcx", "r11");
+  asm("syscall" : "=a"(return_code) : "D"(number), "S"(first) : "rcx", "r11");
   return return_code;
 }
-
-z_err_t SysCall0(uint64_t number) { return SysCall2(number, 0, 0); }
-
-z_err_t SysCall1(uint64_t number, const void* first) {
-  return SysCall2(number, first, 0);
-}
-
-z_err_t ZCapDuplicate(z_cap_t cap_in, z_cap_t* cap_out) {
-  ZCapDuplicateReq req{
-      .cap = cap_in,
-  };
-  ZCapDuplicateResp resp;
-  z_err_t ret = SysCall2(Z_CAP_DUPLICATE, &req, &resp);
-  *cap_out = resp.cap;
-  return ret;
-}
-
-z_err_t ZDebug(const char* message) { return SysCall1(Z_DEBUG_PRINT, message); }
diff --git a/zion/usr/zcall_internal.h b/zion/usr/zcall_internal.h
index 9f5c122..fa25ea5 100644
--- a/zion/usr/zcall_internal.h
+++ b/zion/usr/zcall_internal.h
@@ -11,11 +11,3 @@ struct ZMessage {
   uint64_t num_caps;
   z_cap_t* caps;
 };
-
-struct ZCapDuplicateReq {
-  z_cap_t cap;
-};
-
-struct ZCapDuplicateResp {
-  z_cap_t cap;
-};