From 743b0a9c834869370cd7fbe70a2f7fa4de8f27c2 Mon Sep 17 00:00:00 2001
From: fulivi <fulivi@users.noreply.github.com>
Date: Wed, 9 May 2018 16:03:21 +0200
Subject: [PATCH] tms9914: fixed handling of GTS aux command.

---
 src/devices/machine/tms9914.cpp | 16 ++++++++++------
 src/devices/machine/tms9914.h   |  1 +
 2 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/src/devices/machine/tms9914.cpp b/src/devices/machine/tms9914.cpp
index 9706f22157b..4f47302a187 100644
--- a/src/devices/machine/tms9914.cpp
+++ b/src/devices/machine/tms9914.cpp
@@ -547,6 +547,7 @@ void tms9914_device::do_swrst()
 	m_rl_state = FSM_RL_LOCS;
 	m_pp_ppas = false;
 	m_c_state = FSM_C_CIDS;
+	m_gts = false;
 
 	update_int();
 	set_accrq(false);
@@ -847,6 +848,7 @@ void tms9914_device::update_fsm()
 		prev_state = m_c_state;
 		if (controller_reset()) {
 			m_c_state = FSM_C_CIDS;
+			m_gts = false;
 			m_c_dly_timer->reset();
 		} else {
 			switch (m_c_state) {
@@ -863,8 +865,13 @@ void tms9914_device::update_fsm()
 			case FSM_C_CACS:
 				if (m_rpp) {
 					m_c_state = FSM_C_CPWS;
+					m_gts = false;
+				} else if (m_gts && !sh_active()) {
+					m_c_state = FSM_C_CSBS;
+					m_gts = false;
+					// This ensures a BO interrupt is generated if TACS is active
+					m_sh_state = FSM_SH_SIDS;
 				}
-				// gts -> CSBS
 				break;
 
 			case FSM_C_CSBS:
@@ -1246,11 +1253,8 @@ void tms9914_device::do_aux_cmd(unsigned cmd , bool set_bit)
 		break;
 
 	case AUXCMD_GTS:
-		if (m_c_state == FSM_C_CACS && !sh_active()) {
-			m_c_state = FSM_C_CSBS;
-			m_ext_state_change = true;
-			// This ensures a BO interrupt is generated if TACS is active
-			m_sh_state = FSM_SH_SIDS;
+		if (m_c_state == FSM_C_CACS) {
+			m_gts = true;
 			update_fsm();
 		}
 		break;
diff --git a/src/devices/machine/tms9914.h b/src/devices/machine/tms9914.h
index 0800b58ef74..2c21b1a4d4b 100644
--- a/src/devices/machine/tms9914.h
+++ b/src/devices/machine/tms9914.h
@@ -160,6 +160,7 @@ private:
 	bool m_hdfa;
 	bool m_hdfe;
 	bool m_rtl;
+	bool m_gts;
 	bool m_rpp;
 	bool m_sic;
 	bool m_sre;