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diff --git a/src/devices/machine/z80ctc.cpp b/src/devices/machine/z80ctc.cpp
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+// license:BSD-3-Clause
+// copyright-holders:Wilbert Pol
+/***************************************************************************
+
+ Z80 CTC (Z8430) implementation
+
+ based on original version (c) 1997, Tatsuyuki Satoh
+
+***************************************************************************/
+
+#include "emu.h"
+#include "z80ctc.h"
+#include "cpu/z80/z80.h"
+#include "cpu/z80/z80daisy.h"
+
+
+
+//**************************************************************************
+// DEBUGGING
+//**************************************************************************
+
+#define VERBOSE 0
+
+#define VPRINTF(x) do { if (VERBOSE) logerror x; } while (0)
+#define VPRINTF_CHANNEL(x) do { if (VERBOSE) m_device->logerror x; } while (0)
+
+
+
+//**************************************************************************
+// CONSTANTS
+//**************************************************************************
+
+// these are the bits of the incoming commands to the CTC
+const int INTERRUPT = 0x80;
+const int INTERRUPT_ON = 0x80;
+//const int INTERRUPT_OFF = 0x00;
+
+const int MODE = 0x40;
+const int MODE_TIMER = 0x00;
+const int MODE_COUNTER = 0x40;
+
+const int PRESCALER = 0x20;
+//const int PRESCALER_256 = 0x20;
+const int PRESCALER_16 = 0x00;
+
+const int EDGE = 0x10;
+const int EDGE_FALLING = 0x00;
+const int EDGE_RISING = 0x10;
+
+const int TRIGGER = 0x08;
+const int TRIGGER_AUTO = 0x00;
+//const int TRIGGER_CLOCK = 0x08;
+
+const int CONSTANT = 0x04;
+const int CONSTANT_LOAD = 0x04;
+//const int CONSTANT_NONE = 0x00;
+
+const int RESET = 0x02;
+//const int RESET_CONTINUE = 0x00;
+const int RESET_ACTIVE = 0x02;
+
+const int CONTROL = 0x01;
+const int CONTROL_VECTOR = 0x00;
+const int CONTROL_WORD = 0x01;
+
+// these extra bits help us keep things accurate
+const int WAITING_FOR_TRIG = 0x100;
+
+
+
+//**************************************************************************
+// LIVE DEVICE
+//**************************************************************************
+
+// device type definition
+const device_type Z80CTC = &device_creator<z80ctc_device>;
+
+//-------------------------------------------------
+// z80ctc_device - constructor
+//-------------------------------------------------
+
+z80ctc_device::z80ctc_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock)
+ : device_t(mconfig, Z80CTC, "Z80 CTC", tag, owner, clock, "z80ctc", __FILE__),
+ device_z80daisy_interface(mconfig, *this),
+ m_intr_cb(*this),
+ m_zc0_cb(*this),
+ m_zc1_cb(*this),
+ m_zc2_cb(*this),
+ m_zc3_cb(*this)
+{
+}
+
+
+//-------------------------------------------------
+// read - standard handler for reading
+//-------------------------------------------------
+
+READ8_MEMBER( z80ctc_device::read )
+{
+ return m_channel[offset & 3].read();
+}
+
+
+//-------------------------------------------------
+// write - standard handler for writing
+//-------------------------------------------------
+
+WRITE8_MEMBER( z80ctc_device::write )
+{
+ m_channel[offset & 3].write(data);
+}
+
+
+//-------------------------------------------------
+// trg0-3 - standard write line handlers for each
+// trigger
+//-------------------------------------------------
+
+WRITE_LINE_MEMBER( z80ctc_device::trg0 ) { m_channel[0].trigger(state); }
+WRITE_LINE_MEMBER( z80ctc_device::trg1 ) { m_channel[1].trigger(state); }
+WRITE_LINE_MEMBER( z80ctc_device::trg2 ) { m_channel[2].trigger(state); }
+WRITE_LINE_MEMBER( z80ctc_device::trg3 ) { m_channel[3].trigger(state); }
+
+
+//-------------------------------------------------
+// device_start - device-specific startup
+//-------------------------------------------------
+
+void z80ctc_device::device_start()
+{
+ m_period16 = attotime::from_hz(m_clock) * 16;
+ m_period256 = attotime::from_hz(m_clock) * 256;
+
+ // resolve callbacks
+ m_intr_cb.resolve_safe();
+ m_zc0_cb.resolve_safe();
+ m_zc1_cb.resolve_safe();
+ m_zc2_cb.resolve_safe();
+ m_zc3_cb.resolve_safe();
+
+ // start each channel
+ m_channel[0].start(this, 0);
+ m_channel[1].start(this, 1);
+ m_channel[2].start(this, 2);
+ m_channel[3].start(this, 3);
+
+ // register for save states
+ save_item(NAME(m_vector));
+}
+
+
+//-------------------------------------------------
+// device_reset - device-specific reset
+//-------------------------------------------------
+
+void z80ctc_device::device_reset()
+{
+ // reset each channel
+ m_channel[0].reset();
+ m_channel[1].reset();
+ m_channel[2].reset();
+ m_channel[3].reset();
+
+ // check for interrupts
+ interrupt_check();
+ VPRINTF(("CTC Reset\n"));
+}
+
+
+
+//**************************************************************************
+// DAISY CHAIN INTERFACE
+//**************************************************************************
+
+//-------------------------------------------------
+// z80daisy_irq_state - return the overall IRQ
+// state for this device
+//-------------------------------------------------
+
+int z80ctc_device::z80daisy_irq_state()
+{
+ VPRINTF(("CTC IRQ state = %d%d%d%d\n", m_channel[0].m_int_state, m_channel[1].m_int_state, m_channel[2].m_int_state, m_channel[3].m_int_state));
+
+ // loop over all channels
+ int state = 0;
+ for (int ch = 0; ch < 4; ch++)
+ {
+ ctc_channel &channel = m_channel[ch];
+
+ // if we're servicing a request, don't indicate more interrupts
+ if (channel.m_int_state & Z80_DAISY_IEO)
+ {
+ state |= Z80_DAISY_IEO;
+ break;
+ }
+ state |= channel.m_int_state;
+ }
+
+ return state;
+}
+
+
+//-------------------------------------------------
+// z80daisy_irq_ack - acknowledge an IRQ and
+// return the appropriate vector
+//-------------------------------------------------
+
+int z80ctc_device::z80daisy_irq_ack()
+{
+ // loop over all channels
+ for (int ch = 0; ch < 4; ch++)
+ {
+ ctc_channel &channel = m_channel[ch];
+
+ // find the first channel with an interrupt requested
+ if (channel.m_int_state & Z80_DAISY_INT)
+ {
+ VPRINTF(("CTC IRQAck ch%d\n", ch));
+
+ // clear interrupt, switch to the IEO state, and update the IRQs
+ channel.m_int_state = Z80_DAISY_IEO;
+ interrupt_check();
+ return m_vector + ch * 2;
+ }
+ }
+
+ //logerror("z80ctc_irq_ack: failed to find an interrupt to ack!\n");
+ return m_vector;
+}
+
+
+//-------------------------------------------------
+// z80daisy_irq_reti - clear the interrupt
+// pending state to allow other interrupts through
+//-------------------------------------------------
+
+void z80ctc_device::z80daisy_irq_reti()
+{
+ // loop over all channels
+ for (int ch = 0; ch < 4; ch++)
+ {
+ ctc_channel &channel = m_channel[ch];
+
+ // find the first channel with an IEO pending
+ if (channel.m_int_state & Z80_DAISY_IEO)
+ {
+ VPRINTF(("CTC IRQReti ch%d\n", ch));
+
+ // clear the IEO state and update the IRQs
+ channel.m_int_state &= ~Z80_DAISY_IEO;
+ interrupt_check();
+ return;
+ }
+ }
+
+ //logerror("z80ctc_irq_reti: failed to find an interrupt to clear IEO on!\n");
+}
+
+
+
+//**************************************************************************
+// INTERNAL STATE MANAGEMENT
+//**************************************************************************
+
+//-------------------------------------------------
+// interrupt_check - look for pending interrupts
+// and update the line
+//-------------------------------------------------
+
+void z80ctc_device::interrupt_check()
+{
+ int state = (z80daisy_irq_state() & Z80_DAISY_INT) ? ASSERT_LINE : CLEAR_LINE;
+ m_intr_cb(state);
+}
+
+
+
+//*************************************************************************
+// CTC CHANNELS
+//**************************************************************************
+
+//-------------------------------------------------
+// ctc_channel - constructor
+//-------------------------------------------------
+
+z80ctc_device::ctc_channel::ctc_channel()
+ : m_mode(0),
+ m_tconst(0),
+ m_down(0),
+ m_extclk(0),
+ m_timer(NULL),
+ m_int_state(0)
+{
+}
+
+
+//-------------------------------------------------
+// start - set up at device start time
+//-------------------------------------------------
+
+void z80ctc_device::ctc_channel::start(z80ctc_device *device, int index)
+{
+ // initialize state
+ m_device = device;
+ m_index = index;
+ m_timer = m_device->machine().scheduler().timer_alloc(FUNC(static_timer_callback), this);
+
+ // register for save states
+ m_device->save_item(NAME(m_mode), m_index);
+ m_device->save_item(NAME(m_tconst), m_index);
+ m_device->save_item(NAME(m_down), m_index);
+ m_device->save_item(NAME(m_extclk), m_index);
+ m_device->save_item(NAME(m_int_state), m_index);
+}
+
+
+//-------------------------------------------------
+// reset - reset the channel
+//-------------------------------------------------
+
+void z80ctc_device::ctc_channel::reset()
+{
+ m_mode = RESET_ACTIVE;
+ m_tconst = 0x100;
+ m_timer->adjust(attotime::never);
+ m_int_state = 0;
+}
+
+
+//-------------------------------------------------
+// period - return the current channel's period
+//-------------------------------------------------
+
+attotime z80ctc_device::ctc_channel::period() const
+{
+ // if reset active, no period
+ if ((m_mode & RESET) == RESET_ACTIVE)
+ return attotime::zero;
+
+ // if counter mode, no real period
+ if ((m_mode & MODE) == MODE_COUNTER)
+ {
+ m_device->logerror("CTC %d is CounterMode : Can't calculate period\n", m_index);
+ return attotime::zero;
+ }
+
+ // compute the period
+ attotime period = ((m_mode & PRESCALER) == PRESCALER_16) ? m_device->m_period16 : m_device->m_period256;
+ return period * m_tconst;
+}
+
+
+//-------------------------------------------------
+// read - read the channel's state
+//-------------------------------------------------
+
+UINT8 z80ctc_device::ctc_channel::read()
+{
+ // if we're in counter mode, just return the count
+ if ((m_mode & MODE) == MODE_COUNTER || (m_mode & WAITING_FOR_TRIG))
+ return m_down;
+
+ // else compute the down counter value
+ else
+ {
+ attotime period = ((m_mode & PRESCALER) == PRESCALER_16) ? m_device->m_period16 : m_device->m_period256;
+
+ VPRINTF_CHANNEL(("CTC clock %f\n",ATTOSECONDS_TO_HZ(period.attoseconds())));
+
+ if (m_timer != NULL)
+ return ((int)(m_timer->remaining().as_double() / period.as_double()) + 1) & 0xff;
+ else
+ return 0;
+ }
+}
+
+
+//-------------------------------------------------
+// write - handle writes to a channel
+//-------------------------------------------------
+
+void z80ctc_device::ctc_channel::write(UINT8 data)
+{
+ // if we're waiting for a time constant, this is it
+ if ((m_mode & CONSTANT) == CONSTANT_LOAD)
+ {
+ VPRINTF_CHANNEL(("CTC ch.%d constant = %02x\n", m_index, data));
+
+ // set the time constant (0 -> 0x100)
+ m_tconst = data ? data : 0x100;
+
+ // clear the internal mode -- we're no longer waiting
+ m_mode &= ~CONSTANT;
+
+ // also clear the reset, since the constant gets it going again
+ m_mode &= ~RESET;
+
+ // if we're in timer mode....
+ if ((m_mode & MODE) == MODE_TIMER)
+ {
+ // if we're triggering on the time constant, reset the down counter now
+ if ((m_mode & TRIGGER) == TRIGGER_AUTO)
+ {
+ attotime curperiod = period();
+ m_timer->adjust(curperiod, m_index, curperiod);
+ }
+
+ // else set the bit indicating that we're waiting for the appropriate trigger
+ else
+ m_mode |= WAITING_FOR_TRIG;
+ }
+
+ // also set the down counter in case we're clocking externally
+ m_down = m_tconst;
+ }
+
+ // if we're writing the interrupt vector, handle it specially
+#if 0 /* Tatsuyuki Satoh changes */
+ // The 'Z80family handbook' wrote,
+ // interrupt vector is able to set for even channel (0 or 2)
+ else if ((data & CONTROL) == CONTROL_VECTOR && (m_index & 1) == 0)
+#else
+ else if ((data & CONTROL) == CONTROL_VECTOR && m_index == 0)
+#endif
+ {
+ m_device->m_vector = data & 0xf8;
+ VPRINTF_CHANNEL(("CTC Vector = %02x\n", m_device->m_vector));
+ }
+
+ // this must be a control word
+ else if ((data & CONTROL) == CONTROL_WORD)
+ {
+ // set the new mode
+ m_mode = data;
+ VPRINTF_CHANNEL(("CTC ch.%d mode = %02x\n", m_index, data));
+
+ // if we're being reset, clear out any pending timers for this channel
+ if ((data & RESET) == RESET_ACTIVE)
+ {
+ m_timer->adjust(attotime::never);
+ // note that we don't clear the interrupt state here!
+ }
+ }
+}
+
+
+//-------------------------------------------------
+// trigger - clock this channel and handle any
+// side-effects
+//-------------------------------------------------
+
+void z80ctc_device::ctc_channel::trigger(UINT8 data)
+{
+ // normalize data
+ data = data ? 1 : 0;
+
+ // see if the trigger value has changed
+ if (data != m_extclk)
+ {
+ m_extclk = data;
+
+ // see if this is the active edge of the trigger
+ if (((m_mode & EDGE) == EDGE_RISING && data) || ((m_mode & EDGE) == EDGE_FALLING && !data))
+ {
+ // if we're waiting for a trigger, start the timer
+ if ((m_mode & WAITING_FOR_TRIG) && (m_mode & MODE) == MODE_TIMER)
+ {
+ attotime curperiod = period();
+ VPRINTF_CHANNEL(("CTC period %s\n", curperiod.as_string()));
+ m_timer->adjust(curperiod, m_index, curperiod);
+ }
+
+ // we're no longer waiting
+ m_mode &= ~WAITING_FOR_TRIG;
+
+ // if we're clocking externally, decrement the count
+ if ((m_mode & MODE) == MODE_COUNTER)
+ {
+ // if we hit zero, do the same thing as for a timer interrupt
+ if (--m_down == 0)
+ timer_callback();
+ }
+ }
+ }
+}
+
+
+//-------------------------------------------------
+// trigger - clock this channel and handle any
+// side-effects
+//-------------------------------------------------
+
+void z80ctc_device::ctc_channel::timer_callback()
+{
+ // down counter has reached zero - see if we should interrupt
+ if ((m_mode & INTERRUPT) == INTERRUPT_ON)
+ {
+ m_int_state |= Z80_DAISY_INT;
+ VPRINTF_CHANNEL(("CTC timer ch%d\n", m_index));
+ m_device->interrupt_check();
+ }
+
+ // generate the clock pulse
+ switch (m_index)
+ {
+ case 0:
+ m_device->m_zc0_cb(1);
+ m_device->m_zc0_cb(0);
+ break;
+ case 1:
+ m_device->m_zc1_cb(1);
+ m_device->m_zc1_cb(0);
+ break;
+ case 2:
+ m_device->m_zc2_cb(1);
+ m_device->m_zc2_cb(0);
+ break;
+ case 3:
+ m_device->m_zc3_cb(1);
+ m_device->m_zc3_cb(0);
+ break;
+ }
+
+ // reset the down counter
+ m_down = m_tconst;
+}