/** lc3_rewind
*
* Backsteps as far as it can.
*/
void lc3_rewind(lc3_state& state)
{
bool interrupt_begin = false;
// Do this until no more changes.
while (!state.undo_stack.empty() && !interrupt_begin)
{
lc3_state_change& last = state.undo_stack.back();
interrupt_begin = (last.changes == LC3_INTERRUPT_BEGIN);
// Backstep
lc3_back(state);
}
}
/** lc3_rewind
*
* Backsteps many instructions
*/
void lc3_rewind(lc3_state& state, unsigned int num)
{
bool interrupt_begin = false;
// Do this num times or until no more changes or until we aren't able.
while (!state.undo_stack.empty() && num > 0 && !interrupt_begin)
{
lc3_state_change& last = state.undo_stack.back();
interrupt_begin = (last.changes == LC3_INTERRUPT_BEGIN);
// Backstep
lc3_back(state);
num--;
}
}
/** lc3_prev_line
*
* Undos the current instruction ignoring subroutines
*/
void lc3_prev_line(lc3_state& state)
{
// Subroutine depth
int depth = 0;
do
{
if (!state.undo_stack.empty())
{
lc3_state_change& last = state.undo_stack.back();
// Can't backstep through interrupt
if (last.changes == LC3_INTERRUPT_BEGIN)
return;
// Get rid of all processed interrupts.
while (last.changes == LC3_INTERRUPT && !state.undo_stack.empty())
{
lc3_back(state);
last = state.undo_stack.back();
}
}
// Execute (Have to do this first you can't assume mem[pc - 1] was the last
// instruction due to jumps.
lc3_back(state);
// Get the instruction that got you where you are.
lc3_instr instr = lc3_decode(state, state.mem[state.pc]);
// If we get a RET instruction JMP R7
if (instr.data.opcode == JMP_INSTR && instr.jmp.base_r == 7)
depth++;
// So if we get a JSR/JSRR or if we get a TRAP and true traps are enabled
if (instr.data.opcode == JSR_INSTR || (instr.data.opcode == TRAP_INSTR && state.true_traps))
depth--;
// Don't have to handle interrupts here...
} while (depth != 0 && !state.halted && !state.undo_stack.empty());
}
/** Entry
*
*
*/
void* LC3RunThread::Entry()
{
///TODO consider writing this without rewriting next_line/prev_line.
int depth = 0;
lc3_instr instr;
bool interrupt_begin = false;
state.halted = 0;
switch(run_mode)
{
case RUNMODE_RUN:
while(!state.halted)
{
lc3_step(state);
if (TestDestroy()) break;
Yield();
}
break;
case RUNMODE_RUNFOR:
if (runtime > 0)
lc3_run(state, runtime);
else
lc3_rewind(state, -runtime);
break;
case RUNMODE_STEP:
lc3_step(state);
break;
case RUNMODE_BACK:
lc3_back(state);
break;
case RUNMODE_FINISH:
depth = 1;
case RUNMODE_NEXTLINE:
// Subroutine depth
do
{
// Get Next Instruction.
instr = lc3_decode(state, state.mem[state.pc]);
// So if we get a JSR/JSRR or if we get a TRAP and true traps are enabled
if (instr.data.opcode == JSR_INSTR || (instr.data.opcode == TRAP_INSTR && state.true_traps))
depth++;
// If we get a RET instruction JMP R7
if (instr.data.opcode == JMP_INSTR && instr.jmp.base_r == 7)
depth--;
// If we get an RTI instruction
if (instr.data.opcode == RTI_INSTR)
depth--;
// Execute
lc3_step(state);
// If we got interrupted
if (state.interrupt_enabled && state.undo_stack.back().changes == LC3_INTERRUPT_BEGIN)
depth++;
if (TestDestroy()) break;
Yield();
}
while (depth != 0 && !state.halted);
break;
case RUNMODE_PREVLINE:
// Subroutine depth
depth = 0;
do
{
if (!state.undo_stack.empty())
{
lc3_state_change& last = state.undo_stack.back();
// Can't backstep through interrupt
if (last.changes == LC3_INTERRUPT_BEGIN)
break;
// Get rid of all processed interrupts.
while (last.changes == LC3_INTERRUPT && !state.undo_stack.empty())
{
lc3_back(state);
last = state.undo_stack.back();
if (TestDestroy()) break;
Yield();
}
}
// Execute (Have to do this first you can't assume mem[pc - 1] was the last
// instruction due to jumps.
lc3_back(state);
// Get the instruction that got you where you are.
lc3_instr instr = lc3_decode(state, state.mem[state.pc]);
// If we get a RET instruction JMP R7
if (instr.data.opcode == JMP_INSTR && instr.jmp.base_r == 7)
depth++;
// So if we get a JSR/JSRR or if we get a TRAP and true traps are enabled
if (instr.data.opcode == JSR_INSTR || (instr.data.opcode == TRAP_INSTR && state.true_traps))
depth--;
if (TestDestroy()) break;
Yield();
// Don't have to handle interrupts here...
}
while (depth != 0 && !state.halted && !state.undo_stack.empty());
break;
case RUNMODE_REWIND:
// Do this until no more changes.
while (!state.undo_stack.empty() && !interrupt_begin)
{
lc3_state_change& last = state.undo_stack.back();
interrupt_begin = (last.changes == LC3_INTERRUPT_BEGIN);
// Backstep
lc3_back(state);
if (TestDestroy()) break;
Yield();
}
break;
}
wxQueueEvent(frame, new wxThreadEvent(wxEVT_COMMAND_RUNTHREAD_COMPLETED));
return NULL;
}
