lsi/m3: Fix floppy regression, add initial software list

New working software list additions
-----------------------------------
M3 Utilities (Release 3) [Steve Hunt]

hash/m3.xml

@@ -0,0 +1,20 @@
+<?xml version="1.0"?>
+<!DOCTYPE softwarelist SYSTEM "softwarelist.dtd">
+
+<!-- license:CC0-1.0 -->
+
+<softwarelist name="m3" description="LSI M-THREE disks">
+
+	<!-- bootable -->
+	<software name="m3utils">
+		<description>M3 Utilities (Release 3)</description>
+		<year>198?</year>
+		<publisher>LSI</publisher>
+		<part name="flop1" interface="floppy_8">
+			<dataarea name="flop" size="1617408">
+				<rom name="m3_utils_cpm22_8ssds.mfm" size="1617408" crc="da1072a2" sha1="fa17616c90efda3e2ceeb06012183bbba3631d34" />
+			</dataarea>
+		</part>
+	</software>
+
+</softwarelist>

src/mame/lsi/m3.cpp

@@ -31,14 +31,13 @@
 
     TODO:
     - Initial PC is currently hacked to f000
-    - Verify/fix floppy hookup (CPU needs to be overclocked?)
+    - Verify/fix floppy hookup
     - Printer interface
     - Buzzer
     - Map the rest of the keys, verify existing keys
     - Switch FDC to 1 MHz for 5.25" drives
 
     Notes:
-    - No offical software available, but a custom version of CP/M
     - Y to boot from floppy, ESC to enter monitor, any other key to
       boot from IDE
 
@@ -56,6 +55,7 @@
 #include "bus/rs232/rs232.h"
 #include "emupal.h"
 #include "screen.h"
+#include "softlist_dev.h"
 
 
 namespace {
@@ -126,7 +126,9 @@ private:
 	void fdc_drq_w(int state);
 	uint8_t fdc_data_r(offs_t offset);
 	void fdc_data_w(offs_t offset, uint8_t data);
-	bool m_nmi_taken = 0;
+
+	bool m_nmi_enabled = false;
+	bool m_nmi_taken = false;
 };
 
 
@@ -451,8 +453,8 @@ void m3_state::fdc_intrq_w(int state)
 {
 	if (state)
 	{
+		m_maincpu->set_input_line(Z80_INPUT_LINE_WAIT, CLEAR_LINE);
 		m_nmi_taken = false;
-		m_maincpu->set_input_line(INPUT_LINE_HALT, CLEAR_LINE);
 	}
 
 	m_ctc->trg1(state);
@@ -461,22 +463,25 @@ void m3_state::fdc_intrq_w(int state)
 void m3_state::fdc_drq_w(int state)
 {
 	if (state)
-		m_maincpu->set_input_line(INPUT_LINE_HALT, CLEAR_LINE);
-
-	if (state && !m_nmi_taken)
 	{
-		m_nmi_taken = true;
-		m_maincpu->pulse_input_line(INPUT_LINE_NMI, attotime::zero);
+		m_maincpu->set_input_line(Z80_INPUT_LINE_WAIT, CLEAR_LINE);
+
+		if (m_nmi_enabled)
+		{
+			m_maincpu->pulse_input_line(INPUT_LINE_NMI, attotime::zero);
+
+			m_nmi_enabled = false;
+			m_nmi_taken = true;
+		}
 	}
 }
 
 uint8_t m3_state::fdc_data_r(offs_t offset)
 {
-	if ((m_fdc->drq_r() == 0) && m_nmi_taken)
+	if (m_nmi_taken && m_fdc->drq_r() == 0)
 	{
-		// cpu tries to read data without drq, halt it and reset pc
-		m_maincpu->set_input_line(INPUT_LINE_HALT, ASSERT_LINE);
-		m_maincpu->set_state_int(Z80_PC, m_maincpu->state_int(Z80_PC) - 2);
+		m_maincpu->set_input_line(Z80_INPUT_LINE_WAIT, ASSERT_LINE);
+		m_maincpu->retry_access();
 
 		return 0;
 	}
@@ -486,13 +491,10 @@ uint8_t m3_state::fdc_data_r(offs_t offset)
 
 void m3_state::fdc_data_w(offs_t offset, uint8_t data)
 {
-	if ((m_fdc->drq_r() == 0) && m_nmi_taken)
+	if (m_nmi_taken && m_fdc->drq_r() == 0)
 	{
-		// cpu tries to write data without drq, halt it and reset pc
-		m_maincpu->set_input_line(INPUT_LINE_HALT, ASSERT_LINE);
-		m_maincpu->set_state_int(Z80_PC, m_maincpu->state_int(Z80_PC) - 2);
-
-		return;
+		m_maincpu->set_input_line(Z80_INPUT_LINE_WAIT, ASSERT_LINE);
+		m_maincpu->retry_access();
 	}
 
 	m_fdc->data_w(data);
@@ -505,7 +507,7 @@ void m3_state::ppi2_pa_w(uint8_t data)
 	// 7-------  not used?
 	// -6------  buzzer
 	// --5-----  not used?
-	// ---4----  unknown (motor?)
+	// ---4----  nmi enable
 	// ----3---  unknown
 	// -----2--  floppy side
 	// ------10  drive select
@@ -521,6 +523,8 @@ void m3_state::ppi2_pa_w(uint8_t data)
 
 	if (floppy)
 		floppy->ss_w(BIT(data, 2));
+
+	m_nmi_enabled = bool(BIT(~data, 4));
 }
 
 uint8_t m3_state::ppi2_pb_r()
@@ -534,6 +538,7 @@ void m3_state::machine_start()
 	save_item(NAME(m_kbd_col));
 	save_item(NAME(m_kbd_row));
 	save_item(NAME(m_kbd_data));
+	save_item(NAME(m_nmi_enabled));
 	save_item(NAME(m_nmi_taken));
 }
 
@@ -541,13 +546,8 @@ void m3_state::machine_reset()
 {
 	m_maincpu->set_pc(0xf000);
 
+	m_nmi_enabled = false;
 	m_nmi_taken = false;
-
-	// floppy motor is always on
-	if (m_floppy[0])
-		m_floppy[0]->get_device()->mon_w(0);
-	if (m_floppy[1])
-		m_floppy[1]->get_device()->mon_w(0);
 }
 
 
@@ -582,7 +582,6 @@ static void m3_floppies(device_slot_interface &device)
 void m3_state::m3(machine_config &config)
 {
 	Z80(config, m_maincpu, 4.9152_MHz_XTAL / 2);
-	m_maincpu->set_clock_scale(1.2f); // needs to be overclocked or its too slow for the floppy
 	m_maincpu->set_addrmap(AS_PROGRAM, &m3_state::mem_map);
 	m_maincpu->set_addrmap(AS_IO, &m3_state::io_map);
 	m_maincpu->set_daisy_config(daisy_chain);
@@ -633,6 +632,8 @@ void m3_state::m3(machine_config &config)
 	FLOPPY_CONNECTOR(config, "fdc:0", m3_floppies, "sa850", floppy_image_device::default_mfm_floppy_formats);
 	FLOPPY_CONNECTOR(config, "fdc:1", m3_floppies, "sa850", floppy_image_device::default_mfm_floppy_formats);
 
+	SOFTWARE_LIST(config, "floppy_list").set_original("m3");
+
 	// keyboard
 	I8035(config, m_kbdmcu, 6.144_MHz_XTAL);
 	m_kbdmcu->set_addrmap(AS_PROGRAM, &m3_state::kbd_mem_map);