HDD r/w: error if r/w overlaps with I/O memory

. break to debugger if single-stepping HDD write: support memory accesses across 64KiB boundary
AppleWin · Dec 9, 2021 · bb6fa80 · bb6fa80
1 parent c594d6e
commit bb6fa80
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Showing 3 changed files with 59 additions and 4 deletions.
diff --git a/source/Debugger/Debug.cpp b/source/Debugger/Debug.cpp
@@ -68,6 +68,8 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 	int  g_nDebugBreakOnInvalid  = 0; // Bit Flags of Invalid Opcode to break on: // iOpcodeType = AM_IMPLIED (BRK), AM_1, AM_2, AM_3
 	int  g_iDebugBreakOnOpcode   = 0;
 	bool g_bDebugBreakOnInterrupt = false;
+	static int g_iDebugBreakOnDmaToOrFromIoMemory = 0;
+	static WORD g_uDebugBreakOnDmaIoMemoryAddr = 0;
 
 	static int  g_bDebugBreakpointHit = 0;	// See: BreakpointHit_t
 
@@ -1251,6 +1253,20 @@ void ClearTempBreakpoints ()
 	}
 }
 
+//===========================================================================
+static int CheckBreakpointsDmaToOrFromIoMemory(void)
+{
+	int res = g_iDebugBreakOnDmaToOrFromIoMemory;
+	g_iDebugBreakOnDmaToOrFromIoMemory = 0;
+	return res;
+}
+
+void DebuggerBreakOnDmaToOrFromIoMemory(WORD addr, bool isDmaToMemory)
+{
+	g_iDebugBreakOnDmaToOrFromIoMemory = isDmaToMemory ? BP_DMA_TO_IO_MEM : BP_DMA_FROM_IO_MEM;
+	g_uDebugBreakOnDmaIoMemoryAddr = addr;
+}
+
 //===========================================================================
 Update_t CmdBreakpoint (int nArgs)
 {
@@ -8307,7 +8323,7 @@ void DebugContinueStepping(const bool bCallerWillUpdateDisplay/*=false*/)
 					g_bDebugBreakpointHit |= BP_HIT_INTERRUPT;
 			}
 
-			g_bDebugBreakpointHit |= CheckBreakpointsIO() | CheckBreakpointsReg();
+			g_bDebugBreakpointHit |= CheckBreakpointsIO() | CheckBreakpointsReg() | CheckBreakpointsDmaToOrFromIoMemory();
 		}
 
 		if (regs.pc == g_nDebugStepUntil || g_bDebugBreakpointHit)
@@ -8334,6 +8350,10 @@ void DebugContinueStepping(const bool bCallerWillUpdateDisplay/*=false*/)
 				pszStopReason = TEXT("PC reads from floating bus or I/O memory");
 			else if (g_bDebugBreakpointHit & BP_HIT_INTERRUPT)
 				sprintf_s(szStopMessage, sizeof(szStopMessage), "Interrupt occurred at $%04X", g_LBR);
+			else if (g_bDebugBreakpointHit & BP_DMA_TO_IO_MEM)
+				sprintf_s(szStopMessage, sizeof(szStopMessage), "HDD DMA to I/O memory $%04X", g_uDebugBreakOnDmaIoMemoryAddr);
+			else if (g_bDebugBreakpointHit & BP_DMA_FROM_IO_MEM)
+				sprintf_s(szStopMessage, sizeof(szStopMessage), "HDD DMA from I/O memory $%04X", g_uDebugBreakOnDmaIoMemoryAddr);
 			else
 				pszStopReason = TEXT("Unknown!");
 

diff --git a/source/Debugger/Debug.h b/source/Debugger/Debug.h
@@ -39,6 +39,8 @@
 		, BP_HIT_MEMW = (1 << 5)
 		, BP_HIT_PC_READ_FLOATING_BUS_OR_IO_MEM = (1 << 6)
 		, BP_HIT_INTERRUPT = (1 << 7)
+		, BP_DMA_TO_IO_MEM = (1 << 8)
+		, BP_DMA_FROM_IO_MEM = (1 << 9)
 	};
 
 	extern int          g_nBreakpoints;
@@ -181,3 +183,4 @@
 	void	DebuggerMouseClick( int x, int y );
 
 	bool	IsDebugSteppingAtFullSpeed(void);
+	void	DebuggerBreakOnDmaToOrFromIoMemory(WORD addr, bool isDmaToMemory);
diff --git a/source/Harddisk.cpp b/source/Harddisk.cpp
@@ -39,6 +39,7 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 #include "SaveState.h"
 #include "YamlHelper.h"
 
+#include "Debugger/Debug.h"
 #include "../resource/resource.h"
 
 /*
@@ -520,7 +521,12 @@ BYTE __stdcall HarddiskInterfaceCard::IORead(WORD pc, WORD addr, BYTE bWrite, BY
 									LPBYTE page = memwrite[dstAddr >> 8];
 									if (!page)
 									{
-										_ASSERT(0);
+										if (g_nAppMode == MODE_STEPPING)
+											DebuggerBreakOnDmaToOrFromIoMemory(dstAddr, true);
+										//else // Show MessageBox?
+
+										pCard->m_notBusyCycle = 0;	// DMA complete
+										bRes = false;
 										break;
 									}
 
@@ -535,7 +541,8 @@ BYTE __stdcall HarddiskInterfaceCard::IORead(WORD pc, WORD addr, BYTE bWrite, BY
 									remaining -= size;
 								}
 							}
-							else
+
+							if (!bRes)
 							{
 								pHDD->m_error = 1;
 								r = DEVICE_IO_ERROR;
@@ -568,7 +575,32 @@ BYTE __stdcall HarddiskInterfaceCard::IORead(WORD pc, WORD addr, BYTE bWrite, BY
 								}
 							}
 
-							memcpy(pHDD->m_buf, mem + pHDD->m_memblock, HD_BLOCK_SIZE);
+							// Trap and error on any accesses that overlap with I/O memory
+							if ((pHDD->m_memblock < 0xC000 && ((pHDD->m_memblock + HD_BLOCK_SIZE - 1) >= 0xC000))	// 1) Starts before I/O, but ends in I/O memory
+								|| ((pHDD->m_memblock >> 12) == 0xC))												// 2) Starts in I/O memory
+							{
+								WORD dstAddr = ((pHDD->m_memblock >> 12) == 0xC) ? pHDD->m_memblock : 0xC000;
+
+								if (g_nAppMode == MODE_STEPPING)
+									DebuggerBreakOnDmaToOrFromIoMemory(dstAddr, false);
+								//else // Show MessageBox?
+
+								pCard->m_notBusyCycle = 0;	// DMA complete
+								bRes = false;
+							}
+							else
+							{
+								if (pHDD->m_memblock <= 0xFE00)
+								{
+									memcpy(pHDD->m_buf, mem + pHDD->m_memblock, HD_BLOCK_SIZE);
+								}
+								else // wraps on 64KiB boundary
+								{
+									const UINT size = 0x10000 - pHDD->m_memblock;
+									memcpy(pHDD->m_buf, mem + pHDD->m_memblock, size);
+									memcpy(pHDD->m_buf + size, mem, HD_BLOCK_SIZE - size);
+								}
+							}
 
 							if (bRes)
 								bRes = ImageWriteBlock(pHDD->m_imagehandle, pHDD->m_diskblock, pHDD->m_buf);