harness: per-window busy state machines for the big windows

harness/mame/test_vt1200_board.cpp

@@ -49,6 +49,23 @@ static void test_busy_bit_arms_on_write_and_clears(void)
     CHECK((b.read(status) & 0x0001) == 0x0000);   // done
 }
 
+static void test_windows_are_independent(void)
+{
+    vt1200_board b;
+    b.set_model_handshake(true);
+    b.set_window_busy_ticks(VT1200_WIN2, 1);
+    b.set_window_busy_ticks(VT1200_WIN3, 3);
+
+    b.write(VT1200_WIN2 + VT1200_OFF_CMD, 0x0001);
+    b.write(VT1200_WIN3 + VT1200_OFF_CMD, 0x0001);
+    CHECK((b.read(VT1200_WIN2 + VT1200_OFF_STATUS) & 1) == 1);
+    CHECK((b.read(VT1200_WIN3 + VT1200_OFF_STATUS) & 1) == 1);
+
+    b.tick();
+    CHECK((b.read(VT1200_WIN2 + VT1200_OFF_STATUS) & 1) == 0);   // WIN2 finished
+    CHECK((b.read(VT1200_WIN3 + VT1200_OFF_STATUS) & 1) == 1);   // WIN3 still busy
+}
+
 static void test_monitor_switch_accepts_raw_bits_or_position(void)
 {
     vt1200_board raw;
@@ -75,6 +92,7 @@ int main(void)
     test_override_read();
     test_monitor_switch_is_mixed_with_latches();
     test_busy_bit_arms_on_write_and_clears();
+    test_windows_are_independent();
     test_monitor_switch_accepts_raw_bits_or_position();
     test_switch_mix_only_when_configured();
     std::printf(failures ? "%d FAILURE(S)\n" : "all board tests passed\n", failures);

harness/mame/vt1200_board.cpp

@@ -23,7 +23,8 @@ uint16_t vt1200_board::read(uint32_t addr)
 
 	if (m_handshake && (addr & 0xffff) == VT1200_OFF_STATUS)
 	{
-		if (m_busy_left > 0)
+		auto busy = m_busy_left.find(addr & 0xffff0000);
+		if (busy != m_busy_left.end() && busy->second > 0)
 			value |= 0x0001;
 		else
 			value &= ~0x0001;
@@ -35,11 +36,17 @@ void vt1200_board::write(uint32_t addr, uint16_t data)
 {
 	m_store[addr] = data;
 	if (m_handshake && (addr & 0xffff) == VT1200_OFF_CMD)
-		m_busy_left = m_busy_ticks;
+	{
+		const uint32_t win = addr & 0xffff0000;
+		auto ticks = m_busy_ticks_by_win.find(win);
+		m_busy_left[win] = (ticks != m_busy_ticks_by_win.end()) ? ticks->second : 0;
+	}
 }
 
 void vt1200_board::tick()
 {
-	if (m_busy_left > 0)
-		m_busy_left--;
+	// Advance every window's state machine, not just the one last touched.
+	for (auto &entry : m_busy_left)
+		if (entry.second > 0)
+			entry.second--;
 }

harness/mame/vt1200_board.h

@@ -40,7 +40,18 @@ public:
 	void set_default(uint16_t v)                 { m_default = v; }
 	void set_override(uint32_t addr, uint16_t v) { m_override[addr] = v; }
 	void set_model_handshake(bool on)            { m_handshake = on; }
-	void set_busy_ticks(int n)                   { m_busy_ticks = n; }
+
+	// Per-window busy counts.  Each of the four windows owns its own count, so
+	// the two big windows (0x06200000 and 0x06400000) can be tuned
+	// independently.  set_busy_ticks is shorthand that applies to every window.
+	void set_busy_ticks(int n)
+	{
+		m_busy_ticks_by_win[VT1200_WIN0] = n;
+		m_busy_ticks_by_win[VT1200_WIN1] = n;
+		m_busy_ticks_by_win[VT1200_WIN2] = n;
+		m_busy_ticks_by_win[VT1200_WIN3] = n;
+	}
+	void set_window_busy_ticks(uint32_t window_base, int n) { m_busy_ticks_by_win[window_base] = n; }
 
 	// Monitor switch (bits 4-6 of the switch port).  The argument is accepted
 	// unambiguously as EITHER the raw register bits (e.g. 0x70) OR a small
@@ -66,8 +77,11 @@ private:
 	std::map<uint32_t, uint16_t> m_override;   // fixed values (experiments)
 	uint16_t m_default = 0;
 	bool     m_handshake = false;
-	int      m_busy_ticks = 0;
-	int      m_busy_left = 0;
+	// Busy state machines, keyed by window base (addr & 0xffff0000): how many
+	// ticks each window stays busy after a command write, and the remaining
+	// count for the command currently in flight.
+	std::map<uint32_t, int> m_busy_ticks_by_win;
+	std::map<uint32_t, int> m_busy_left;
 	bool     m_switch_set = false;             // set_monitor_switch was called
 	uint16_t m_switch_bits = 0;
 };