terak: add minimal LSI-11 CPU core

src/devices/cpu/t11/t11.cpp

@@ -36,10 +36,24 @@
 
 
 DEFINE_DEVICE_TYPE(T11,      t11_device,      "t11",      "DEC T11")
+DEFINE_DEVICE_TYPE(LSI11,    lsi11_device,    "lsi11",    "DEC LSI-11")
 DEFINE_DEVICE_TYPE(K1801VM1, k1801vm1_device, "k1801vm1", "K1801VM1")
 DEFINE_DEVICE_TYPE(K1801VM2, k1801vm2_device, "k1801vm2", "K1801VM2")
 
 
+/*
+ * Not implemented:
+ *
+ * instruction timing, microcode-related insns, HALT state and ODT,
+ * traps: double bus error and bus error on vector fetch.
+ */
+lsi11_device::lsi11_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
+	: t11_device(mconfig, LSI11, tag, owner, clock)
+	, z80_daisy_chain_interface(mconfig, *this)
+{
+	c_insn_set = IS_LEIS | IS_MXPS; // EISFIS is an option
+}
+
 /*
  * Not implemented:
  *
@@ -223,6 +237,83 @@ static const struct irq_table_entry irq_table[] =
 	{ 7<<5, 0140 }
 };
 
+// priorities from LSI-11 Processor Handbook, p. 4-70
+void lsi11_device::t11_check_irqs()
+{
+	int8_t              mcir = MCIR_NONE;
+	uint16_t            vsel = 0;
+
+	if (m_mcir != MCIR_NONE)
+	{
+		mcir = m_mcir;
+		vsel = m_vsel;
+	}
+	// 1. bus error
+	else if (m_bus_error)
+	{
+		m_bus_error = false;
+		mcir = MCIR_IRQ;
+		vsel = T11_TIMEOUT;
+	}
+	// 3. illegal insn
+	else if (mcir == MCIR_ILL)
+	{
+		take_interrupt(vsel);
+	}
+	// 4. trace trap
+	else if (m_trace_trap)
+	{
+		if (GET_T)
+		{
+			mcir = MCIR_IRQ;
+			vsel = T11_BPT;
+		}
+		else
+			m_trace_trap = false;
+	}
+	else if (GET_T)
+	{
+		m_trace_trap = true;
+	}
+	// 5. halt line (B HALT L bus signal) -- FIXME not implemented
+	// 6. power fail (B POK H bus signal)
+	else if (m_power_fail)
+	{
+		m_power_fail = false;
+		mcir = MCIR_IRQ;
+		vsel = T11_PWRFAIL;
+	}
+	// 7. event line (B EVNT L bus signal)
+	else if (m_cp[2] && !GET_I)
+	{
+		m_cp[2] = false;
+		mcir = MCIR_IRQ;
+		vsel = VM1_EVNT;
+	}
+	// 8. device interrupt (B IRQ4 L bus signal)
+	else if (m_vec_active && !GET_I)
+	{
+		device_z80daisy_interface *intf = daisy_get_irq_device();
+		int vec = (intf != nullptr) ? intf->z80daisy_irq_ack() : m_in_iack_func(0);
+		if (vec == -1 || vec == 0)
+		{
+			m_vec_active = 0;
+			return;
+		}
+		else
+		{
+			mcir = MCIR_IRQ;
+			vsel = vec;
+		}
+	}
+
+	if (mcir == MCIR_IRQ)
+		take_interrupt(vsel);
+
+	m_mcir = MCIR_NONE;
+}
+
+
 // PSW7 masks external interrupts (except IRQ1) -- IRQ2, IRQ3, VIRQ
 // PSW11 also masks IRQ1.  PSW10 also masks ACLO.
 void k1801vm1_device::t11_check_irqs()

src/devices/cpu/t11/t11.h

@@ -1196,6 +1196,16 @@ class t11_device :  public cpu_device
 	void sub_ixd_ixd(uint16_t op);
 };
 
+class lsi11_device : public t11_device, public z80_daisy_chain_interface
+{
+public:
+	// construction/destruction
+	lsi11_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock);
+
+protected:
+	virtual void t11_check_irqs() override;
+};
+
 class k1801vm1_device : public t11_device, public z80_daisy_chain_interface
 {
 public:
@@ -1230,6 +1240,7 @@ class k1801vm2_device : public t11_device, public z80_daisy_chain_interface
 
 
 DECLARE_DEVICE_TYPE(T11,      t11_device)
+DECLARE_DEVICE_TYPE(LSI11,    lsi11_device)
 DECLARE_DEVICE_TYPE(K1801VM1, k1801vm1_device)
 DECLARE_DEVICE_TYPE(K1801VM2, k1801vm2_device)
 

src/mame/skeleton/terak.cpp

@@ -12,8 +12,10 @@ Floppies were 8 inch IBM format.
 ****************************************************************************/
 
 #include "emu.h"
-//#include "bus/qbus/qbus.h"
+
+#include "bus/qbus/qbus.h"
 #include "cpu/t11/t11.h"
+
 #include "emupal.h"
 #include "screen.h"
 
@@ -26,6 +28,7 @@ class terak_state : public driver_device
 	terak_state(const machine_config &mconfig, device_type type, const char *tag)
 		: driver_device(mconfig, type, tag)
 		, m_maincpu(*this, "maincpu")
+		, m_qbus(*this, "qbus")
 	{ }
 
 	void terak(machine_config &config);
@@ -41,9 +44,14 @@ class terak_state : public driver_device
 
 	uint8_t m_unit = 0;
 	uint8_t m_cmd = 0;
+
 	virtual void machine_reset() override ATTR_COLD;
 	virtual void video_start() override ATTR_COLD;
-	required_device<t11_device> m_maincpu;
+
+	void reset_w(int state);
+
+	required_device<lsi11_device> m_maincpu;
+	required_device<qbus_device> m_qbus;
 };
 
 uint16_t terak_state::terak_fdc_status_r()
@@ -91,6 +99,12 @@ static INPUT_PORTS_START( terak )
 INPUT_PORTS_END
 
 
+static const z80_daisy_config daisy_chain[] =
+{
+	{ "qbus" },
+	{ nullptr }
+};
+
 void terak_state::machine_reset()
 {
 }
@@ -104,13 +118,23 @@ uint32_t terak_state::screen_update_terak(screen_device &screen, bitmap_ind16 &b
 	return 0;
 }
 
+void terak_state::reset_w(int state)
+{
+	if (state == ASSERT_LINE)
+	{
+		m_qbus->init_w();
+	}
+}
+
 
 void terak_state::terak(machine_config &config)
 {
 	/* basic machine hardware */
-	T11(config, m_maincpu, 4'000'000); // FIXME: actually LSI-11
+	LSI11(config, m_maincpu, 4'000'000);
 	m_maincpu->set_initial_mode(6 << 13);
 	m_maincpu->set_addrmap(AS_PROGRAM, &terak_state::mem_map);
+	m_maincpu->set_daisy_config(daisy_chain);
+	m_maincpu->out_reset().set(FUNC(terak_state::reset_w));
 
 	/* video hardware */
 	screen_device &screen(SCREEN(config, "screen", SCREEN_TYPE_RASTER));
@@ -122,11 +146,21 @@ void terak_state::terak(machine_config &config)
 	screen.set_palette("palette");
 
 	PALETTE(config, "palette", palette_device::MONOCHROME);
+
+	QBUS(config, m_qbus, 0);
+	m_qbus->set_space(m_maincpu, AS_PROGRAM);
+	m_qbus->bevnt().set_inputline(m_maincpu, t11_device::CP2_LINE);
+	m_qbus->birq4().set_inputline(m_maincpu, t11_device::VEC_LINE);
+	QBUS_SLOT(config, "qbus" ":1", qbus_cards, nullptr);
+	QBUS_SLOT(config, "qbus" ":2", qbus_cards, nullptr);
+	QBUS_SLOT(config, "qbus" ":3", qbus_cards, nullptr);
+	QBUS_SLOT(config, "qbus" ":4", qbus_cards, nullptr);
 }
 
 /* ROM definition */
 ROM_START( terak )
 	ROM_REGION( 0x10000, "maincpu", ROMREGION_ERASEFF )
+	// QX disk bootstrap
 	ROM_LOAD( "terak.rom", 0173000, 0x0080, CRC(fd654b8e) SHA1(273a9933b68a290c5aedcd6d69faa7b1d22c0344))
 
 	ROM_REGION( 0x2000, "kbd", 0)