From 89eb0cb07b229e9edf6e03db7a26c3bdee5fc28c Mon Sep 17 00:00:00 2001
From: tomcw <tomcw@users.noreply.github.com>
Date: Wed, 1 Mar 2023 21:01:59 +0000
Subject: [PATCH] Mockingboard: After AY is reset, then latched addr isn't
 valid . Save-state: save all 8 bits of latched addr. . Debugger: for mini-AY
 dump, show latched addr (current register shown in white)

---
 source/Debugger/Debugger_Display.cpp | 18 ++++++++++++++----
 source/Mockingboard.cpp              | 16 ++++++++++++----
 source/Mockingboard.h                |  6 ++++--
 3 files changed, 30 insertions(+), 10 deletions(-)

diff --git a/source/Debugger/Debugger_Display.cpp b/source/Debugger/Debugger_Display.cpp
index bf40598e..2ce9b0be 100644
--- a/source/Debugger/Debugger_Display.cpp
+++ b/source/Debugger/Debugger_Display.cpp
@@ -2094,11 +2094,21 @@ void DrawMemory ( int line, int iMemDump )
 			{
 				if (SS_MB.Hdr.UnitHdr.hdr.v2.Type == UT_Card)
 				{
-					sText = StrFormat("%02X ", (unsigned)SS_MB.Unit[nAddr & 1].RegsAY8910[iAddress]);
-					if (iCol & 1)
-						DebuggerSetColorFG(DebuggerGetColor(iForeground));
+					if (iAddress <= 13)
+						sText = StrFormat("%02X ", (unsigned)SS_MB.Unit[nAddr & 1].RegsAY8910[iAddress]);
 					else
-						DebuggerSetColorFG(DebuggerGetColor(FG_INFO_ADDRESS));
+						sText = "-- ";	// regs 14 & 15 aren't supported by AY-3-8913
+					if (SS_MB.Unit[nAddr & 1].nAYCurrentRegister == iAddress)
+					{
+						DebuggerSetColorFG(DebuggerGetColor(FG_INFO_TITLE));							// if latched address then draw in white
+					}
+					else
+					{
+						if (iCol & 1)
+							DebuggerSetColorFG(DebuggerGetColor(iForeground));
+						else
+							DebuggerSetColorFG(DebuggerGetColor(FG_INFO_ADDRESS));
+					}
 				}
 				else
 				{
diff --git a/source/Mockingboard.cpp b/source/Mockingboard.cpp
index 92f432a8..4d29e927 100644
--- a/source/Mockingboard.cpp
+++ b/source/Mockingboard.cpp
@@ -240,6 +240,9 @@ void MockingboardCard::AY8910_Write(BYTE subunit, BYTE ay, BYTE value)
 	{
 		// RESET: Reset AY8910 only
 		AY8910_reset(subunit, ay);
+		pMB->nAYCurrentRegister = 0;	// not valid
+		pMB->state = pMB->stateB = AY_INACTIVE;
+		pMB->isAYLatchedAddressValid[0] = pMB->isAYLatchedAddressValid[1] = false;
 	}
 	else
 	{
@@ -270,7 +273,9 @@ void MockingboardCard::AY8910_Write(BYTE subunit, BYTE ay, BYTE value)
 					break;
 
 				case AY_WRITE:		// 6: WRITE TO PSG
-					_AYWriteReg(subunit, ay, pMB->nAYCurrentRegister, r6522.GetReg(SY6522::rORA));
+					if (pMB->isAYLatchedAddressValid[ay])
+						_AYWriteReg(subunit, ay, pMB->nAYCurrentRegister, r6522.GetReg(SY6522::rORA));
+					// else if invalid then just ignore
 					break;
 
 				case AY_LATCH:		// 7: LATCH ADDRESS
@@ -279,7 +284,10 @@ void MockingboardCard::AY8910_Write(BYTE subunit, BYTE ay, BYTE value)
 					// any values written to the data/address bus are ignored, but can be read back
 					// within a few tens of thousands of cycles before they decay to zero.
 					if (r6522.GetReg(SY6522::rORA) <= 0x0F)
+					{
 						pMB->nAYCurrentRegister = r6522.GetReg(SY6522::rORA) & 0x0F;
+						pMB->isAYLatchedAddressValid[ay] = true;
+					}
 					// else Pro-Mockingboard (clone from HK)
 					break;
 			}
@@ -929,7 +937,7 @@ void MockingboardCard::GetSnapshot_v1(SS_CARD_MOCKINGBOARD_v1* const pSS)
 		}
 
 		memset(&pSS->Unit[i].RegsSSI263, 0, sizeof(SSI263A));	// Not used by debugger
-		pSS->Unit[i].nAYCurrentRegister = pMB->nAYCurrentRegister;
+		pSS->Unit[i].nAYCurrentRegister = pMB->isAYLatchedAddressValid[0] ? pMB->nAYCurrentRegister : 0xff;
 		pSS->Unit[i].bTimer1Active = pMB->sy6522.IsTimer1Active();
 		pSS->Unit[i].bTimer2Active = pMB->sy6522.IsTimer2Active();
 		pSS->Unit[i].bSpeechIrqPending = false;
@@ -1092,7 +1100,7 @@ void MockingboardCard::SaveSnapshot(YamlSaveHelper& yamlSaveHelper)
 		pMB->ssi263.SaveSnapshot(yamlSaveHelper);
 
 		yamlSaveHelper.SaveHexUint4(SS_YAML_KEY_MB_UNIT_STATE, pMB->state);
-		yamlSaveHelper.SaveHexUint4(SS_YAML_KEY_AY_CURR_REG, pMB->nAYCurrentRegister);
+		yamlSaveHelper.SaveHexUint8(SS_YAML_KEY_AY_CURR_REG, pMB->nAYCurrentRegister);	// save all 8 bits (even though top 4 bits should be 0)
 	}
 }
 
@@ -1185,7 +1193,7 @@ void MockingboardCard::Phasor_SaveSnapshot(YamlSaveHelper& yamlSaveHelper)
 
 		yamlSaveHelper.SaveHexUint4(SS_YAML_KEY_MB_UNIT_STATE, pMB->state);
 		yamlSaveHelper.SaveHexUint4(SS_YAML_KEY_MB_UNIT_STATE_B, pMB->stateB);
-		yamlSaveHelper.SaveHexUint4(SS_YAML_KEY_AY_CURR_REG, pMB->nAYCurrentRegister);
+		yamlSaveHelper.SaveHexUint8(SS_YAML_KEY_AY_CURR_REG, pMB->nAYCurrentRegister);	// save all 8 bits (even though top 4 bits should be 0)
 	}
 }
 
diff --git a/source/Mockingboard.h b/source/Mockingboard.h
index 6299e8ef..7400902a 100644
--- a/source/Mockingboard.h
+++ b/source/Mockingboard.h
@@ -66,13 +66,15 @@ private:
 		BYTE nAYCurrentRegister;
 		MockingboardUnitState_e state;	// Where a unit is a 6522+AY8910 pair
 		MockingboardUnitState_e stateB;	// Phasor: 6522 & 2nd AY8910
+		bool isAYLatchedAddressValid[2];
 
 		MB_SUBUNIT(UINT slot) : sy6522(slot), ssi263(slot)
 		{
 			nAY8910Number = 0;
 			nAYCurrentRegister = 0;
-			state = AY_NOP0;
-			stateB = AY_NOP0;
+			state = AY_INACTIVE;
+			stateB = AY_INACTIVE;
+			isAYLatchedAddressValid[0] = isAYLatchedAddressValid[1] = false;	// after AY reset
 			// sy6522 & ssi263 have already been default constructed
 		}
 	};