void Reset (bool fPress_)
{
// Set CPU operating mode
g_fReset = fPress_;
if (g_fReset)
{
// Certain registers are initialised on every reset
I = R = R7 = IFF1 = IFF2 = 0;
PC = 0x0000;
regs.halted = 0;
bOpcode = 0x00; // not after EI
// Index prefix not active
pHlIxIy = pNewHlIxIy = &HL;
// Clear the CPU events queue
InitCpuEvents();
// Schedule the first end of line event, and an update check 3/4 through the frame
AddCpuEvent(evtEndOfFrame, TSTATES_PER_FRAME);
AddCpuEvent(evtInputUpdate, TSTATES_PER_FRAME*3/4);
// Re-initialise memory (for configuration changes) and reset I/O
IO::Init();
Memory::Init();
// Refresh the debugger and re-test breakpoints
Debug::Refresh();
}
// Set up the fast reset for first power-on
else if (GetOption(fastreset))
g_nTurbo |= TURBO_BOOT;
}
void Tape::NextEdge (DWORD dwTime_)
{
libspectrum_error error;
if (fEar)
keyboard |= BORD_EAR_MASK;
else
keyboard &= ~BORD_EAR_MASK;
if (!g_nTurbo)
pDAC->Output(fEar ? 0xa0 : 0x80);
libspectrum_dword tstates;
int nFlags;
// Fetch details of the next edge, and the time until it's due
error = libspectrum_tape_get_next_edge(&tstates, &nFlags, pTape);
if (error)
{
Stop();
return;
}
if (nFlags & LIBSPECTRUM_TAPE_FLAGS_LEVEL_LOW)
fEar = false;
else if (nFlags & LIBSPECTRUM_TAPE_FLAGS_LEVEL_HIGH)
fEar = true;
else if (!(nFlags & LIBSPECTRUM_TAPE_FLAGS_NO_EDGE))
fEar = !fEar;
// End of tape block?
if ((nFlags & LIBSPECTRUM_TAPE_FLAGS_BLOCK))
{
// Stop the tape as it'll restart when required
Stop();
}
else
{
// Timings are in 3.5MHz t-states, so convert to SAM t-states
tstates = tstates*(REAL_TSTATES_PER_SECOND/1000) + tremain;
libspectrum_dword tadd = tstates/(SPECTRUM_TSTATES_PER_SECOND/1000);
tremain = tstates % (SPECTRUM_TSTATES_PER_SECOND/1000);
// Schedule an event to activate the edge
AddCpuEvent(evtTapeEdge, dwTime_+tadd);
}
}
// Execute the CPU event specified
void ExecuteEvent (CPU_EVENT sThisEvent)
{
switch (sThisEvent.nEvent)
{
case evtStdIntEnd:
// Reset the interrupt as we're done
status_reg |= (STATUS_INT_FRAME | STATUS_INT_LINE);
break;
case evtMidiOutIntStart:
// Begin the MIDI_OUT interrupt and add an event to end it
status_reg &= ~STATUS_INT_MIDIOUT;
AddCpuEvent(evtMidiOutIntEnd, sThisEvent.dwTime + MIDI_INT_ACTIVE_TIME);
break;
case evtMidiOutIntEnd:
// Reset the interrupt and clear the 'transmitting' bit in LPEN as we're done
status_reg |= STATUS_INT_MIDIOUT;
lpen &= ~LPEN_TXFMST;
break;
case evtLineIntStart:
{
// Begin the line interrupt and add an event to end it
status_reg &= ~STATUS_INT_LINE;
AddCpuEvent(evtStdIntEnd, sThisEvent.dwTime + INT_ACTIVE_TIME);
AddCpuEvent(evtLineIntStart, sThisEvent.dwTime + TSTATES_PER_FRAME);
break;
}
case evtEndOfFrame:
{
// Signal a FRAME interrupt, and start the interrupt counter
status_reg &= ~STATUS_INT_FRAME;
AddCpuEvent(evtStdIntEnd, sThisEvent.dwTime + INT_ACTIVE_TIME);
AddCpuEvent(evtEndOfFrame, sThisEvent.dwTime + TSTATES_PER_FRAME);
// Signal end of the frame
g_fBreak = true;
break;
}
case evtInputUpdate:
// Update the input in the centre of the screen (well away from the frame boundary) to avoid the ROM
// keyboard scanner discarding key presses when it thinks keys have bounced. In old versions this was
// the cause of the first key press on the boot screen only clearing it (took AGES to track down!)
IO::UpdateInput();
// Schedule the next input check at the same position in the next frame
AddCpuEvent(evtInputUpdate, sThisEvent.dwTime + TSTATES_PER_FRAME);
break;
case evtMouseReset:
pMouse->Reset();
break;
case evtBlueAlphaClock:
// Clock the sampler, scheduling the next event if it's still running
if (pBlueAlpha->Clock())
AddCpuEvent(evtBlueAlphaClock, sThisEvent.dwTime + BLUE_ALPHA_CLOCK_TIME);
break;
case evtAsicStartup:
// ASIC is now responsive
IO::WakeAsic();
break;
case evtTapeEdge:
Tape::NextEdge(sThisEvent.dwTime);
break;
}
}
