From cf722ff0ccaecc10154ae2a2f9a267fa237736fd Mon Sep 17 00:00:00 2001
From: tomcw <tomcw@users.noreply.github.com>
Date: Sun, 29 Jan 2023 13:32:55 +0000
Subject: [PATCH] Fix so that MockingboardCardMgr asserts IRQ based on the
 wired-OR sum of all MB card's 6522s. (Fixes #1173)

---
 source/6522.cpp                    |  2 +-
 source/Mockingboard.cpp            | 11 ++++-------
 source/Mockingboard.h              |  2 +-
 source/MockingboardCardManager.cpp | 16 ++++++++++++++++
 source/MockingboardCardManager.h   |  1 +
 5 files changed, 23 insertions(+), 9 deletions(-)

diff --git a/source/6522.cpp b/source/6522.cpp
index 5c43fc21..8922773d 100644
--- a/source/6522.cpp
+++ b/source/6522.cpp
@@ -128,7 +128,7 @@ void SY6522::UpdateIFR(BYTE clr_ifr, BYTE set_ifr /*= 0*/)
 		m_regs.IFR &= ~IFR_IRQ;
 
 	if (GetCardMgr().GetObj(m_slot))	// If called from MockingboardCard ctor, then CardManager::m_slot[slot] == NULL
-		dynamic_cast<MockingboardCard&>(GetCardMgr().GetRef(m_slot)).UpdateIRQ();
+		GetCardMgr().GetMockingboardCardMgr().UpdateIRQ();
 }
 
 //-----------------------------------------------------------------------------
diff --git a/source/Mockingboard.cpp b/source/Mockingboard.cpp
index 6738d1f8..86aa6879 100644
--- a/source/Mockingboard.cpp
+++ b/source/Mockingboard.cpp
@@ -288,13 +288,13 @@ void MockingboardCard::UpdateIFRandIRQ(MB_SUBUNIT* pMB, BYTE clr_mask, BYTE set_
 //---------------------------------------------------------------------------
 
 // Called from class SY6522
-void MockingboardCard::UpdateIRQ(void)
+bool MockingboardCard::Is6522IRQ(void)
 {
 	// Now update the IRQ signal from all 6522s
 	// . OR-sum of all active TIMER1, TIMER2 & SPEECH sources (from all 6522s)
-	UINT bIRQ = 0;
+	bool irq = false;
 	for (UINT i = 0; i < NUM_SUBUNITS_PER_MB; i++)
-		bIRQ |= m_MBSubUnit[i].sy6522.GetReg(SY6522::rIFR) & 0x80;
+		irq |= m_MBSubUnit[i].sy6522.GetReg(SY6522::rIFR) & 0x80 ? true : false;
 
 	// NB. Mockingboard generates IRQ on both 6522s:
 	// . SSI263's IRQ (A/!R) is routed via the 2nd 6522 (at $Cn80) and must generate a 6502 IRQ (not NMI)
@@ -302,10 +302,7 @@ void MockingboardCard::UpdateIRQ(void)
 	// . SC-01's IRQ (A/!R) is routed via the 6522 at $Cn00 (NB. Only the Mockingboard "Sound/Speech I" card supports the SC-01)
 	// Phasor's SSI263 IRQ (A/!R) line is *also* wired directly to the 6502's IRQ (as well as the 6522's CA1)
 
-	if (bIRQ)
-	    CpuIrqAssert(IS_6522);
-	else
-	    CpuIrqDeassert(IS_6522);
+	return irq;
 }
 
 //---------------------------------------------------------------------------
diff --git a/source/Mockingboard.h b/source/Mockingboard.h
index 081b5281..6299e8ef 100644
--- a/source/Mockingboard.h
+++ b/source/Mockingboard.h
@@ -43,7 +43,7 @@ public:
 	void Get6522IrqDescription(std::string& desc);
 #endif
 
-	void UpdateIRQ(void);
+	bool Is6522IRQ(void);
 	UINT64 GetLastCumulativeCycles(void);
 	void UpdateIFR(BYTE nDevice, BYTE clr_mask, BYTE set_mask);
 	BYTE GetPCR(BYTE nDevice);
diff --git a/source/MockingboardCardManager.cpp b/source/MockingboardCardManager.cpp
index 48935f09..c08bfded 100644
--- a/source/MockingboardCardManager.cpp
+++ b/source/MockingboardCardManager.cpp
@@ -32,6 +32,7 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 #include "MockingboardCardManager.h"
 #include "Core.h"
 #include "CardManager.h"
+#include "CPU.h"
 #include "Mockingboard.h"
 #include "MockingboardDefs.h"
 #include "Riff.h"
@@ -108,6 +109,21 @@ void MockingboardCardManager::UpdateCycles(ULONG executedCycles)
 	}
 }
 
+void MockingboardCardManager::UpdateIRQ(void)
+{
+	bool irq = false;
+	for (UINT i = SLOT0; i < NUM_SLOTS; i++)
+	{
+		if (IsMockingboard(i))
+			irq |= dynamic_cast<MockingboardCard&>(GetCardMgr().GetRef(i)).Is6522IRQ();
+	}
+
+	if (irq)
+		CpuIrqAssert(IS_6522);
+	else
+		CpuIrqDeassert(IS_6522);
+}
+
 bool MockingboardCardManager::IsActive(void)
 {
 	if (!m_mockingboardVoice.bActive)
diff --git a/source/MockingboardCardManager.h b/source/MockingboardCardManager.h
index 10172d4e..8e6e7681 100644
--- a/source/MockingboardCardManager.h
+++ b/source/MockingboardCardManager.h
@@ -26,6 +26,7 @@ public:
 	void MuteControl(bool mute);
 	void SetCumulativeCycles(void);
 	void UpdateCycles(ULONG executedCycles);
+	void UpdateIRQ(void);
 	bool IsActive(void);
 	DWORD GetVolume(void);
 	void SetVolume(DWORD volume, DWORD volumeMax);