diff options
Diffstat (limited to 'SrcShared/ATraps.cpp')
| -rw-r--r-- | SrcShared/ATraps.cpp | 453 |
1 files changed, 453 insertions, 0 deletions
diff --git a/SrcShared/ATraps.cpp b/SrcShared/ATraps.cpp new file mode 100644 index 0000000..91bbbf2 --- /dev/null +++ b/SrcShared/ATraps.cpp @@ -0,0 +1,453 @@ +/* -*- mode: C++; tab-width: 4 -*- */ +/* ===================================================================== *\ + Copyright (c) 1998-2001 Palm, Inc. or its subsidiaries. + All rights reserved. + + This file is part of the Palm OS Emulator. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2 of the License, or + (at your option) any later version. +\* ===================================================================== */ + +// --------------------------------------------------------------------------- +#pragma mark ===== Includes +// --------------------------------------------------------------------------- + +#include "EmCommon.h" +#include "ATraps.h" + +#include "Byteswapping.h" // Canonical +#include "EmBankMapped.h" // EmBankMapped::GetEmulatedAddress +#include "EmCPU68K.h" // GetRegisters +#include "EmException.h" // EmExceptionReset +#include "EmPalmOS.h" // EmPalmOS +#include "EmSession.h" // gSession +#include "ErrorHandling.h" // Errors::ReportError +#include "Miscellaneous.h" // StMemoryMapper +#include "EmPalmFunction.h" // GetTrapName +#include "Profiling.h" // StDisableAllProfiling + + +// --------------------------------------------------------------------------- +#pragma mark ===== Types +// --------------------------------------------------------------------------- + + +// --------------------------------------------------------------------------- +#pragma mark ===== Functions +// --------------------------------------------------------------------------- + +static Bool PrvHandleTrap12 (ExceptionNumber); + + +// --------------------------------------------------------------------------- +#pragma mark ===== Constants +// --------------------------------------------------------------------------- + +const uint16 kOpcode_ROMCall = m68kTrapInstr + sysDispatchTrapNum; +const uint16 kOpcode_ATrapReturn = m68kTrapInstr + kATrapReturnTrapNum; + + +// --------------------------------------------------------------------------- +#pragma mark ===== Variables +// --------------------------------------------------------------------------- + +// ----- Saved variables ----------------------------------------------------- + +// ----- UnSaved variables --------------------------------------------------- + + +#pragma mark - + +// =========================================================================== +// ¥ ATrap +// =========================================================================== + +/*********************************************************************** + * + * FUNCTION: ATrap::ATrap + * + * DESCRIPTION: . + * + * PARAMETERS: None. + * + * RETURNED: Nothing. + * + ***********************************************************************/ + +ATrap::ATrap (void) : +#if (__GNUC__ < 2) +/* Can't call the default constructor because there isn't one defined */ +/* on a struct as there is with a class under GCC 2.8.1 */ + fNewRegisters (), +#endif + fEmulatedStackMapper (this->GetStackBase (), kStackSize) +{ + // Get the registers. + + EmAssert (gCPU68K); + gCPU68K->GetRegisters (fOldRegisters); + fNewRegisters = fOldRegisters; + + // Make sure the CPU is not stopped. I suppose that we could force the CPU + // to no longer be stopped, but I'd rather that the Palm OS itself woke up + // first before we try making calls into it. Therefore, anything making + // an out-of-the-blue Palm OS call via this class (that is, a call outside + // of the context of a Palm OS function head- or tailpatch) should first + // bring the CPU to a halt by calling EmSession::ExecuteUntilSysCall first. + + EmAssert (fNewRegisters.stopped == 0); + + // Give ourselves our own private stack. We'll want this in case + // we're in the debugger and the stack pointer is hosed. + + m68k_areg (fNewRegisters, 7) = EmBankMapped::GetEmulatedAddress ( + this->GetStackBase () + kStackSize - 4); + + // Remember this as a stack so that our stack sniffer won't complain. + + char* stackBase = this->GetStackBase (); + StackRange range ( EmBankMapped::GetEmulatedAddress (&stackBase[0]), + EmBankMapped::GetEmulatedAddress (&stackBase[kStackSize - 4])); + EmPalmOS::RememberStackRange (range); +} + + +/*********************************************************************** + * + * FUNCTION: ATrap::~ATrap + * + * DESCRIPTION: . + * + * PARAMETERS: None. + * + * RETURNED: Nothing. + * + ***********************************************************************/ + +ATrap::~ATrap (void) +{ + // Put things back the way they were. + + EmPalmOS::ForgetStack (EmBankMapped::GetEmulatedAddress (this->GetStackBase ())); + + EmAssert (gCPU68K); + gCPU68K->SetRegisters (fOldRegisters); + + // Check to see if anything interesting was registered while we + // were making the Palm OS subroutine call. The "check after end + // of cycle" bit may have gotten cleared when restoring the old + // registers, so set it on the off chance that it was. Doing this + // is harmless if there really aren't any scheduled tasks. + + EmAssert (gSession); + gCPU68K->CheckAfterCycle (); +} + + +/*********************************************************************** + * + * FUNCTION: ATrap::Call + * + * DESCRIPTION: Calls the given pseudo-ATrap. + * + * PARAMETERS: None. + * + * RETURNED: Nothing. + * + ***********************************************************************/ + +void ATrap::Call (uint16 trapWord) +{ + EmAssert (trapWord != sysTrapSysReset); + + // Up until now, the registers in "regs" have been left alone. If any + // values were pushed on the stack, the stack position was reflected in + // fNewRegisters. Now's the time to move those values from fNewRegisters + // to regs. + + EmAssert (gCPU68K); + gCPU68K->SetRegisters (fNewRegisters); + + // Make the call. + + this->DoCall(trapWord); + + // Remember the resulting register values so that we can report them to + // the user when they call GetD0 and/or GetA0. + + gCPU68K->GetRegisters (fNewRegisters); +} + + +/*********************************************************************** + * + * FUNCTION: ATrap::PushByte + * + * DESCRIPTION: . + * + * PARAMETERS: None. + * + * RETURNED: Nothing. + * + ***********************************************************************/ + +void ATrap::PushByte (uint8 iByte) +{ + StDisableAllProfiling stopper; + + m68k_areg (fNewRegisters, 7) -= 2; + EmMemPut8 (m68k_areg (fNewRegisters, 7), iByte); +} + + +/*********************************************************************** + * + * FUNCTION: ATrap::PushWord + * + * DESCRIPTION: . + * + * PARAMETERS: None. + * + * RETURNED: Nothing. + * + ***********************************************************************/ + +void ATrap::PushWord (uint16 iWord) +{ + StDisableAllProfiling stopper; + + m68k_areg (fNewRegisters, 7) -= 2; + EmMemPut16 (m68k_areg (fNewRegisters, 7), iWord); +} + + +/*********************************************************************** + * + * FUNCTION: ATrap::PushLong + * + * DESCRIPTION: . + * + * PARAMETERS: None. + * + * RETURNED: Nothing. + * + ***********************************************************************/ + +void ATrap::PushLong (uint32 iLong) +{ + StDisableAllProfiling stopper; + + m68k_areg (fNewRegisters, 7) -= 4; + EmMemPut32 (m68k_areg (fNewRegisters, 7), iLong); +} + + +/*********************************************************************** + * + * FUNCTION: ATrap::SetNewDReg + * + * DESCRIPTION: . + * + * PARAMETERS: None. + * + * RETURNED: Nothing. + * + ***********************************************************************/ + +void ATrap::SetNewDReg (int regNum, uint32 value) +{ + m68k_dreg (fNewRegisters, regNum) = value; +} + + +/*********************************************************************** + * + * FUNCTION: ATrap::SetNewAReg + * + * DESCRIPTION: . + * + * PARAMETERS: None. + * + * RETURNED: Nothing. + * + ***********************************************************************/ + +void ATrap::SetNewAReg (int regNum, uint32 value) +{ + m68k_areg (fNewRegisters, regNum) = value; +} + + +/*********************************************************************** + * + * FUNCTION: ATrap::GetD0 + * + * DESCRIPTION: . + * + * PARAMETERS: None. + * + * RETURNED: Nothing. + * + ***********************************************************************/ + +uint32 ATrap::GetD0 (void) +{ + return m68k_dreg (fNewRegisters, 0); +} + + +/*********************************************************************** + * + * FUNCTION: ATrap::GetA0 + * + * DESCRIPTION: . + * + * PARAMETERS: None. + * + * RETURNED: Nothing. + * + ***********************************************************************/ + +uint32 ATrap::GetA0 (void) +{ + return m68k_areg (fNewRegisters, 0); +} + + +/*********************************************************************** + * + * FUNCTION: ATrap::DoCall + * + * DESCRIPTION: Calls the pseudo-ATrap. When we return, D0 or A0 should + * hold the result, the parameters will still be on the + * stack with the SP pointing to them, and the PC will be + * restored to what it was before this function was called. + * + * PARAMETERS: None. + * + * RETURNED: Nothing. + * + ***********************************************************************/ + +void ATrap::DoCall (uint16 trapWord) +{ + // Stop all profiling activities. Stop cycle counting and stop the + // recording of function entries and exits. We want our calls to + // ROM functions to be as transparent as possible. + + StDisableAllProfiling stopper; + + + // Assert that the function we're trying to call is implemented. + // + // Oops...bad test...this doesn't work when we're calling a library. + // Instead, since we now invoke ROM functions by creating a TRAP $F + // sequence, we'll let our TRAP $F handler deal with validating the + // function call (it does that anyway). + +// EmAssert (LowMem::GetTrapAddress (trapWord)); + + // We call the ROM function by dummying up a sequence of 68xxx instructions + // for it. The sequence of instructions is: + // + // TRAP $F + // DC.W <dispatch number> + // TRAP $C + // + // The first two words invoke the function (calling any head- or tailpatches + // along the way). The third word allows the emulator to regain control + // after the function has returned. + // + // Note: this gets a little ugly on little-endian machines. The following + // instructions are stored on the emulator's stack. This memory is mapped + // into the emulated address space in such a fashion that no byteswapping of + // word or long values occurs. Thus, we have to put the data into Big Endian + // format when putting it into the array. + // + // However, opcodes are a special case. They are optimized in the emulator + // for fast access. Opcodes are *always* fetched a word at a time in host- + // endian order. Thus, the opcodes below have to be stored in host-endian + // order. That's why there's no call to Canonical to put them into Big + // Endian order. + + uint16 code[] = { kOpcode_ROMCall, trapWord, kOpcode_ATrapReturn }; + + // Oh, OK, we do have to byteswap the trapWord. Opcodes are fetched with + // EmMemDoGet16, which always gets the value in host byte order. The + // trapWord is fetched with EmMemGet16, which gets values according to the + // rules of the memory bank. For the dummy bank, the defined byte order + // is Big Endian. + + Canonical (code[1]); + + // Map in the code stub so that the emulation code can access it. + + StMemoryMapper mapper (code, sizeof (code)); + + // Prepare to handle the TRAP 12 exception. + + EmAssert (gCPU68K); + gCPU68K->InstallHookException (kException_ATrapReturn, PrvHandleTrap12); + + // Point the PC to our code. + + emuptr newPC = EmBankMapped::GetEmulatedAddress (code); + m68k_setpc (newPC); + + // Execute until the next break. + + try + { + EmAssert (gSession); + gSession->ExecuteSubroutine (); + } + catch (EmExceptionReset& e) + { + e.SetTrapWord (trapWord); + + // Remove the TRAP 12 exception handler. + + EmAssert (gCPU68K); + gCPU68K->RemoveHookException (kException_ATrapReturn, PrvHandleTrap12); + + throw; + } + + // Remove the TRAP 12 exception handler. + + EmAssert (gCPU68K); + gCPU68K->RemoveHookException (kException_ATrapReturn, PrvHandleTrap12); +} + + +// --------------------------------------------------------------------------- +// ¥ ATrap::GetStackBase +// --------------------------------------------------------------------------- + +char* ATrap::GetStackBase () +{ + // Ensure that the stack is aligned to a longword address. + + uint32 stackBase = (uint32) fStack; + + stackBase += 3; + stackBase &= ~3; + + return (char*) stackBase; +} + + +// --------------------------------------------------------------------------- +// ¥ PrvHandleTrap12 +// --------------------------------------------------------------------------- + +Bool PrvHandleTrap12 (ExceptionNumber) +{ + EmAssert (gSession); + gSession->ScheduleSuspendSubroutineReturn (); + + return true; +} |