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Debugger step-over can fail (#1194, PR #1203)

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. QoL cleanup (show RTS address) for step-over failure cases
. Add source code for repro test 1 and 2
This commit is contained in:
Michael "Code Poet" Pohoreski 2023-03-31 01:45:54 -07:00 committed by GitHub
parent 4e8006456f
commit a3c6156508
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3 changed files with 154 additions and 46 deletions
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114
source/Debugger/Debug.cpp
View File

@ -2294,7 +2294,8 @@ Update_t CmdStepOver (int nArgs)
while (nDebugSteps -- > 0)
{
int nOpcode = *(mem + regs.pc); // g_nDisasmCurAddress
int nOpcode = *(mem + regs.pc);
WORD nExpectedAddr = (regs.pc + 3) & _6502_MEM_END; // Wrap around 64K edge case when PC = $FFFD..$FFFF: 20 xx xx
// int eMode = g_aOpcodes[ nOpcode ].addrmode;
// int nByte = g_aOpmodes[eMode]._nBytes;
// if ((eMode == AM_A) &&
@ -2302,10 +2303,80 @@ Update_t CmdStepOver (int nArgs)
CmdTrace(0);
if (nOpcode == OPCODE_JSR)
{
/*
Repro #2 Test when SP <= 0x01 before JSR and _6502_GetStackReturnAddress() fetch return address
300:BA 86 FF A2 01 9A 20 0D 03 A6 FF 9A 60 A9 FF 20 A8 FC 60
BPX 306
MD1 100
MD2 1E0
ORG $300
TSX ; 300
STX $FF ; 301
LDX #1 ; 303
TXS ; 305
JSR DelayFF ; 306
LDX $FF ; 309
TXS ; 30B
RTS ; 30C
DelayFF LDA #$FF ; 30D
JSR $FCA8 ; 30F
RTS ; 312
*/
CmdStepOut(0);
g_nDebugSteps = 0xFFFF;
int nMaxSteps = 0xFFFFF; // GH #1194
g_nDebugSteps = nMaxSteps;
while (g_nDebugSteps != 0)
{
DebugContinueStepping(true);
}
// If the PC isn't at the expected address after the JSR print a diagnostic so the user knows the stack may be buggered up
if (regs.pc != nExpectedAddr)
{
WORD nActualAddr = _6502_GetStackReturnAddress();
bool bValidAddr = (nActualAddr == nExpectedAddr);
int nStackOffset = _6502_FindStackReturnAddress( nExpectedAddr ); // Trace stack to seee if our expected address is on it
/*
ORG $300
Main JSR HugeWait
RTS
HugeWait LDY #$FF
Loop JSR Delay
DEY
BNE Loop
RTS
Delay LDA #$FF
JSR $FCA8
RTS
Repro #1
1. MSVC: Revert line to repro: int nMaxSteps = 0xFFFF;
2. MSVC: Set BP on line above: (regs.pc != nExpectedAddr)
3. AppleWin:
F7
300:A0 FF 20 09 03 88 D0 FA 60 A9 FF 20 A8 FC 60
BPX 30B
F7
CALL 768
<Ctrl>-<Space>
4. MSVC:Change regs.sp to one of 3 cases:
Case Addr On Stack Top of Stack Diagnostic nStackOffset R SP Continue in emulator
0 No No ERROR -1 regs.sp = 0x1F3
1 Yes Yes INFO O regs.sp = 0x1F2 R PC FCB3
2 Yes No WARN +1 regs.sp = 0x1F1 R S F1
*/
/**/ if (nStackOffset < 0) ConsolePrintFormat( CHC_ERROR "ERROR" CHC_ARG_SEP ":" CHC_ERROR " Didn't step over JSR! " CHC_ARG_SEP "(" CHC_DEFAULT "RTS " CHC_ARG_SEP "$" CHC_ADDRESS "%04X" CHC_DEFAULT " not found!" CHC_ARG_SEP ")", nExpectedAddr ); // Case 0
else if (nStackOffset == 0) ConsolePrintFormat( CHC_INFO "INFO" CHC_ARG_SEP ":" CHC_INFO " Didn't step over JSR! " CHC_ARG_SEP "(" CHC_DEFAULT "RTS " CHC_ARG_SEP "$" CHC_ADDRESS "%04X" CHC_DEFAULT " on top of stack." CHC_ARG_SEP ")", nExpectedAddr ); // Case 1
else /* */ ConsolePrintFormat( CHC_WARNING "WARN" CHC_ARG_SEP ":" CHC_WARNING " Didn't step over JSR! " CHC_ARG_SEP "(" CHC_DEFAULT "Stack has RTS " CHC_ARG_SEP "$" CHC_ADDRESS "%04X" CHC_DEFAULT " but needs fixup: " CHC_ARG_SEP "$" CHC_NUM_HEX "%02X" CHC_DEFAULT " bytes" CHC_ARG_SEP ")", nExpectedAddr, nStackOffset & 0xFF ); // Case 2
ConsolePrintFormat( CHC_DEFAULT " Please report '" CHC_SYMBOL "nMaxSteps" CHC_ARG_SEP " = " CHC_DEFAULT "0x" CHC_NUM_HEX "%04X" CHC_DEFAULT "' to:", nMaxSteps );
ConsolePrintFormat( CHC_PATH " https://github.com/AppleWin/AppleWin/issues/1194" );
ConsoleUpdate();
}
}
}
@ -2317,13 +2388,11 @@ Update_t CmdStepOut (int nArgs)
{
// TODO: "RET" should probably pop the Call stack
// Also see: CmdCursorJumpRetAddr
WORD nAddress;
if (_6502_GetStackReturnAddress( nAddress ))
{
nArgs = _Arg_1( nAddress );
g_aArgs[1].sArg[0] = 0;
CmdGo( 1, true );
}
WORD nAddress = _6502_GetStackReturnAddress();
nArgs = _Arg_1( nAddress );
g_aArgs[1].sArg[0] = 0;
CmdGo( 1, true );
return UPDATE_ALL;
}
@ -3296,22 +3365,19 @@ Update_t CmdCursorJumpPC (int nArgs)
//===========================================================================
Update_t CmdCursorJumpRetAddr (int nArgs)
{
WORD nAddress = 0;
if (_6502_GetStackReturnAddress( nAddress ))
{
g_nDisasmCurAddress = nAddress;
WORD nAddress = _6502_GetStackReturnAddress();
g_nDisasmCurAddress = nAddress;
if (CURSOR_ALIGN_CENTER == nArgs)
{
WindowUpdateDisasmSize();
}
else
if (CURSOR_ALIGN_TOP == nArgs)
{
g_nDisasmCurLine = 0;
}
DisasmCalcTopBotAddress();
if (CURSOR_ALIGN_CENTER == nArgs)
{
WindowUpdateDisasmSize();
}
else
if (CURSOR_ALIGN_TOP == nArgs)
{
g_nDisasmCurLine = 0;
}
DisasmCalcTopBotAddress();
return UPDATE_ALL;
}
@ -8609,7 +8675,7 @@ void DebugContinueStepping (const bool bCallerWillUpdateDisplay/*=false*/)
bool skipStopReason = false;
if (regs.pc == g_nDebugStepUntil)
stopReason = "PC matches 'Go until' address";
stopReason = StrFormat( CHC_DEFAULT "Register " CHC_REGS "PC" CHC_DEFAULT " matches '" CHC_INFO "Go until" CHC_DEFAULT "' address $" CHC_ADDRESS "%04X", g_nDebugStepUntil);
else if (g_bDebugBreakpointHit & BP_HIT_INVALID)
stopReason = "Invalid opcode";
else if (g_bDebugBreakpointHit & BP_HIT_OPCODE)

78
source/Debugger/Debugger_Assembler.cpp
View File

@ -426,8 +426,64 @@ Fx BEQ r SBC (d),Y sbc (z) --- --- SBC d,X INC z,X --- SED SBC a,Y
void AssemblerHashOpcodes ();
void AssemblerHashDirectives ();
// Implementation ___________________________________________________________
// Utility __________________________________________________________________
// === Stack ===
// Return stack offset if the address is on the stack, else -1 if not found
//===========================================================================
int _6502_FindStackReturnAddress (const WORD nAddress)
{
WORD nReturnAddress;
WORD nStack = regs.sp + 1;
int nDepth = -1; // not found
// Normally would <= _6502_STACK_END-1 since JSR always pushes 2 bytes
// but the SP could be $00 before JSR forcing RTS address to be split $100/$1FF
// or the SP could be $01 before JSR forcing RTS address to be at $100/$101
// R PC 300
// R S 0
// 300:20 04 03 60 60
// <Ctrl-Space>
while (nStack <= (_6502_STACK_END + 1))
{
nReturnAddress = _6502_PeekStackReturnAddress(nStack);
if (nReturnAddress == nAddress)
{
nDepth = (nStack - 2 - regs.sp);
return nDepth;
}
}
return nDepth;
}
// NOTE: If the stack pointer is <= 01 before a JSR the stack will wrap around.
//===========================================================================
WORD _6502_GetStackReturnAddress ()
{
WORD nStack = regs.sp + 1;
WORD nAddress = _6502_PeekStackReturnAddress(nStack);
return nAddress;
}
// NOTES: nStack is both an input and output;
// If nStack is 0x1FF it WILL return overflow 0x200. Current callers are:
// _6502_FindStackReturnAddress(), and
// _6502_GetStackReturnAddress()
// which DON'T return this overflow stack value to previous callers.
//===========================================================================
WORD _6502_PeekStackReturnAddress (WORD & nStack)
{
WORD nAddress;
nAddress = ((unsigned) *(LPBYTE)(mem + 0x100 + (nStack & 0xFF)) ); nStack++;
nAddress += ((unsigned) *(LPBYTE)(mem + 0x100 + (nStack & 0xFF)) << 8);
nAddress++;
return nAddress;
}
// == Opcodes ===
//===========================================================================
bool _6502_CalcRelativeOffset ( int nOpcode, int nBaseAddress, int nTargetAddress, WORD * pTargetOffset_ )
@ -464,7 +520,6 @@ bool _6502_CalcRelativeOffset ( int nOpcode, int nBaseAddress, int nTargetAddres
return false;
}
//===========================================================================
int _6502_GetOpmodeOpbyte ( const int nBaseAddress, int & iOpmode_, int & nOpbyte_, const DisasmData_t** pData_ )
{
@ -566,25 +621,6 @@ void _6502_GetOpcodeOpmodeOpbyte (int & iOpcode_, int & iOpmode_, int & nOpbyte_
iOpcode_ = _6502_GetOpmodeOpbyte( regs.pc, iOpmode_, nOpbyte_ );
}
//===========================================================================
bool _6502_GetStackReturnAddress (WORD & nAddress_)
{
unsigned nStack = regs.sp;
nStack++;
if (nStack <= (_6502_STACK_END - 1))
{
nAddress_ = (unsigned)*(LPBYTE)(mem + nStack);
nStack++;
nAddress_ += ((unsigned)*(LPBYTE)(mem + nStack)) << 8;
nAddress_++;
return true;
}
return false;
}
//===========================================================================
bool _6502_GetTargets (WORD nAddress, int *pTargetPartial_, int *pTargetPartial2_, int *pTargetPointer_, int * pTargetBytes_,
bool bIgnoreBranch /*= true*/, bool bIncludeNextOpcodeAddress /*= true*/ )

8
source/Debugger/Debugger_Assembler.h
View File

@ -191,15 +191,21 @@ extern int g_aAssemblerFirstDirective[ NUM_ASSEMBLERS ];
// Prototypes _______________________________________________________________
// Stack
int _6502_FindStackReturnAddress (const WORD nAddress);
WORD _6502_GetStackReturnAddress ();
WORD _6502_PeekStackReturnAddress (WORD & nStack);
// Opcodes
int _6502_GetOpmodeOpbyte( const int iAddress, int & iOpmode_, int & nOpbytes_, const DisasmData_t** pData = NULL );
void _6502_GetOpcodeOpmodeOpbyte( int & iOpcode_, int & iOpmode_, int & nOpbytes_ );
bool _6502_GetStackReturnAddress( WORD & nAddress_ );
bool _6502_GetTargets( WORD nAddress, int *pTargetPartial_, int *pTargetPartial2_, int *pTargetPointer_, int * pBytes_,
bool bIgnoreBranch = true, bool bIncludeNextOpcodeAddress = true );
bool _6502_GetTargetAddress( const WORD & nAddress, WORD & nTarget_ );
bool _6502_IsOpcodeBranch( int nOpcode );
bool _6502_IsOpcodeValid( int nOpcode );
// Assembler
Hash_t AssemblerHashMnemonic ( const TCHAR * pMnemonic );
// bool AssemblerGetAddressingMode ( int iArg, int nArgs, WORD nAddress, std::vector<int> & vOpcodes );
void _CmdAssembleHashDump ();