diff --git a/src/devices/machine/68340.cpp b/src/devices/machine/68340.cpp
index b9ddd9c4b16..f65c820ab33 100644
--- a/src/devices/machine/68340.cpp
+++ b/src/devices/machine/68340.cpp
@@ -32,11 +32,11 @@ int m68340_calc_cs(m68340cpu_device *m68k, offs_t address)
 
 
 
-UINT16 m68340_get_cs(m68340cpu_device *device, offs_t address)
+UINT16 m68340cpu_device::get_cs(offs_t address)
 {
-	device->m68340_currentcs = m68340_calc_cs(device, address);
+	m68340_currentcs = m68340_calc_cs(this, address);
 
-	return device->m68340_currentcs;
+	return m68340_currentcs;
 }
 
 
diff --git a/src/devices/machine/68340.h b/src/devices/machine/68340.h
index 4dd93bb6e51..5e9d4b5d908 100644
--- a/src/devices/machine/68340.h
+++ b/src/devices/machine/68340.h
@@ -38,6 +38,8 @@ public:
 	UINT16 m_picr;
 	UINT16 m_pitr;
 
+	UINT16 get_cs(offs_t address);
+
 	READ32_MEMBER( m68340_internal_base_r );
 	WRITE32_MEMBER( m68340_internal_base_w );
 	READ32_MEMBER( m68340_internal_dma_r );
@@ -66,8 +68,6 @@ protected:
 
 static const device_type M68340 = &device_creator<m68340cpu_device>;
 
-extern UINT16 m68340_get_cs(m68340cpu_device *device, offs_t address);
-
 
 
 
diff --git a/src/mame/drivers/astrafr.cpp b/src/mame/drivers/astrafr.cpp
index 37d0f4c4997..34a6523d8a7 100644
--- a/src/mame/drivers/astrafr.cpp
+++ b/src/mame/drivers/astrafr.cpp
@@ -133,7 +133,7 @@ public:
 READ32_MEMBER(astrafr_state::astrafr_mem_r)
 {
 	int pc = space.device().safe_pc();
-	int cs = m68340_get_cs(m_maincpu, offset * 4);
+	int cs = m_maincpu->get_cs(offset * 4);
 
 	switch ( cs )
 	{
@@ -161,7 +161,7 @@ WRITE32_MEMBER(astrafr_state::astrafr_mem_w)
 {
 	int pc = space.device().safe_pc();
 	int address = offset * 4;
-	int cs = m68340_get_cs(m_maincpu, address);
+	int cs = m_maincpu->get_cs(address);
 
 
 	switch ( cs )
@@ -190,7 +190,7 @@ WRITE32_MEMBER(astrafr_state::astrafr_mem_w)
 READ32_MEMBER(astrafr_state::astrafr_slave_mem_r)
 {
 	int pc = space.device().safe_pc();
-	int cs = m68340_get_cs(m_slavecpu, offset * 4);
+	int cs = m_slavecpu->get_cs(offset * 4);
 
 	switch ( cs )
 	{
@@ -216,7 +216,7 @@ WRITE32_MEMBER(astrafr_state::astrafr_slave_mem_w)
 {
 	int pc = space.device().safe_pc();
 	int address = offset * 4;
-	int cs = m68340_get_cs(m_slavecpu, address);
+	int cs = m_slavecpu->get_cs(address);
 
 
 	switch ( cs )
diff --git a/src/mame/drivers/bfm_sc4.cpp b/src/mame/drivers/bfm_sc4.cpp
index f967baa9050..a7b65a0688f 100644
--- a/src/mame/drivers/bfm_sc4.cpp
+++ b/src/mame/drivers/bfm_sc4.cpp
@@ -624,7 +624,7 @@ ADDRESS_MAP_END
 READ32_MEMBER(sc4_adder4_state::adder4_mem_r)
 {
 	int pc = space.device().safe_pc();
-	int cs = m68340_get_cs(m_adder4cpu, offset * 4);
+	int cs = m_adder4cpu->get_cs(offset * 4);
 
 	switch ( cs )
 	{
@@ -646,7 +646,7 @@ READ32_MEMBER(sc4_adder4_state::adder4_mem_r)
 WRITE32_MEMBER(sc4_adder4_state::adder4_mem_w)
 {
 	int pc = space.device().safe_pc();
-	int cs = m68340_get_cs(m_adder4cpu, offset * 4);
+	int cs = m_adder4cpu->get_cs(offset * 4);
 
 	switch ( cs )
 	{
diff --git a/src/mame/drivers/bfm_swp.cpp b/src/mame/drivers/bfm_swp.cpp
index 5198984a975..6c7c91e0730 100644
--- a/src/mame/drivers/bfm_swp.cpp
+++ b/src/mame/drivers/bfm_swp.cpp
@@ -136,7 +136,7 @@ protected:
 READ32_MEMBER(bfm_swp_state::bfm_swp_mem_r)
 {
 	int pc = space.device().safe_pc();
-	int cs = m68340_get_cs(m_maincpu, offset * 4);
+	int cs = m_maincpu->get_cs(offset * 4);
 
 	switch ( cs )
 	{
@@ -158,7 +158,7 @@ READ32_MEMBER(bfm_swp_state::bfm_swp_mem_r)
 WRITE32_MEMBER(bfm_swp_state::bfm_swp_mem_w)
 {
 	int pc = space.device().safe_pc();
-	int cs = m68340_get_cs(m_maincpu, offset * 4);
+	int cs = m_maincpu->get_cs(offset * 4);
 
 	switch ( cs )
 	{
diff --git a/src/mame/drivers/mpu5.cpp b/src/mame/drivers/mpu5.cpp
index 29df7cb8932..d3c6c3cd39d 100644
--- a/src/mame/drivers/mpu5.cpp
+++ b/src/mame/drivers/mpu5.cpp
@@ -281,7 +281,7 @@ READ32_MEMBER(mpu5_state::mpu5_mem_r)
 {
 	int pc = space.device().safe_pc();
 	int addr = offset *4;
-	int cs = m68340_get_cs(m_maincpu, addr);
+	int cs = m_maincpu->get_cs(addr);
 
 	switch ( cs )
 	{
@@ -477,7 +477,7 @@ WRITE32_MEMBER(mpu5_state::mpu5_mem_w)
 {
 	int pc = space.device().safe_pc();
 	int addr = offset *4;
-	int cs = m68340_get_cs(m_maincpu, addr);
+	int cs = m_maincpu->get_cs(addr);
 
 	switch ( cs )
 	{
diff --git a/src/mame/drivers/pluto5.cpp b/src/mame/drivers/pluto5.cpp
index bfb5cb114c9..8cc68881e40 100644
--- a/src/mame/drivers/pluto5.cpp
+++ b/src/mame/drivers/pluto5.cpp
@@ -206,7 +206,7 @@ public:
 READ32_MEMBER(pluto5_state::pluto5_mem_r)
 {
 	int pc = space.device().safe_pc();
-	int cs = m68340_get_cs(m_maincpu, offset * 4);
+	int cs = m_maincpu->get_cs(offset * 4);
 
 	switch ( cs )
 	{
@@ -224,7 +224,7 @@ READ32_MEMBER(pluto5_state::pluto5_mem_r)
 WRITE32_MEMBER(pluto5_state::pluto5_mem_w)
 {
 	int pc = space.device().safe_pc();
-	int cs = m68340_get_cs(m_maincpu, offset * 4);
+	int cs = m_maincpu->get_cs(offset * 4);
 
 	switch ( cs )
 	{