// license:BSD-3-Clause
// copyright-holders:Olivier Galibert
/*********************************************************************
Implementation of the Apple SWIM3 floppy disk controller
*********************************************************************/
#include "emu.h"
#include "swim3.h"
DEFINE_DEVICE_TYPE(SWIM3, swim3_device, "swim3", "Apple SWIM3 (Sander/Wozniak Integrated Machine) version 3 floppy controller")
swim3_device::swim3_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock) :
applefdintf_device(mconfig, SWIM3, tag, owner, clock),
m_irq_cb(*this),
m_drq_cb(*this)
{
}
void swim3_device::device_start()
{
applefdintf_device::device_start();
m_timer = timer_alloc(FUNC(swim3_device::update), this);
save_item(NAME(m_mode));
save_item(NAME(m_setup));
save_item(NAME(m_param));
save_item(NAME(m_irq));
save_item(NAME(m_imask));
save_item(NAME(m_state));
save_item(NAME(m_step));
save_item(NAME(m_error));
save_item(NAME(m_cur_track));
save_item(NAME(m_cur_sector));
save_item(NAME(m_cur_format));
save_item(NAME(m_sect1));
save_item(NAME(m_xfer));
save_item(NAME(m_fifo));
save_item(NAME(m_fifo_pos));
save_item(NAME(m_drq_write));
}
void swim3_device::device_reset()
{
applefdintf_device::device_reset();
m_floppy = nullptr;
m_cur_live.state = L_IDLE;
m_cur_live.tm = attotime::never;
m_mode = 0x00;
m_setup = 0x00;
m_param = 0x77;
m_irq = 0;
m_imask = 0;
m_state = S_IDLE;
m_step = 0;
m_error = 0;
m_cur_track = 0;
m_cur_sector = 0;
m_cur_format = 0;
m_sect1 = 0xff;
m_xfer = 0;
m_fifo[0] = m_fifo[1] = 0;
m_fifo_pos = 0;
m_drq_write = false;
m_devsel_cb(0);
m_sel35_cb(true);
m_hdsel_cb(false);
}
void swim3_device::set_floppy(floppy_image_device *floppy)
{
if(m_floppy == floppy)
return;
if(m_floppy)
m_floppy->setup_index_pulse_cb(floppy_image_device::index_pulse_cb());
logerror("floppy %s\n", floppy ? floppy->tag() : "-");
m_floppy = floppy;
update_phases();
m_hdsel_cb((m_mode >> 5) & 1);
if(m_floppy)
m_floppy->setup_index_pulse_cb(floppy_image_device::index_pulse_cb(&swim3_device::index_callback, this));
}
floppy_image_device *swim3_device::get_floppy() const
{
return m_floppy;
}
void swim3_device::show_mode() const
{
logerror("mode%s%s hdsel=%c %c%s %c%c%s\n",
m_mode & 0x80 ? " step" : "",
m_mode & 0x40 ? " format" : "",
m_mode & 0x20 ? '1' : '0',
m_mode & 0x10 ? 'w' : 'r',
m_mode & 0x08 ? " go" : "",
m_mode & 0x04 ? 'b' : '-',
m_mode & 0x02 ? 'a' : '-',
m_mode & 0x01 ? " irq" : "");
}
u8 swim3_device::read(offs_t offset)
{
static const char *const names[] = {
"data", "timer", "error", "param", "phases", "setup", "?6", "handshake",
"interrupt", "step", "track", "sector", "format", "sect1", "xfer", "imask"
};
switch(offset) {
case 0x2: { // error
u8 r = m_error;
m_error = 0;
return r;
}
case 0x3: // param
return m_param;
case 0x4: // phases
return m_phases & 0xf;
case 0x5: // setup
return m_setup;
case 0x6: // mode
return m_mode;
case 0x7: { // handshake
u8 h = 0;
if(!m_floppy || m_floppy->wpt_r())
h |= 0x0c;
logerror("hand %02x\n", h);
return h;
};
case 0x8: {
u8 res = m_irq;
m_irq = 0;
update_irq();
return res;
}
case 0xa:
return m_cur_track;
case 0xb:
return m_cur_sector;
case 0xc:
return m_cur_format;
case 0xd:
return m_sect1;
case 0xe:
return m_xfer;
case 0xf:
return m_imask;
default:
logerror("read %s\n", names[offset & 15]);
break;
}
return 0xff;
}
void swim3_device::write(offs_t offset, u8 data)
{
u8 prev_mode = m_mode;
static const char *const names[] = {
"data", "timer", "error", "param", "phases", "setup", "mode0", "mode1",
"?8", "step", "track", "sector", "gap", "sect1", "xfer", "imask"
};
switch(offset) {
case 0x3: // param
m_param = data;
logerror("precompensation late=%x early=%x\n", m_param >> 4, m_param & 0xf);
break;
case 0x4: { // phases
m_phases = data | 0xf0;
update_phases();
break;
}
case 0x5: // setup
m_setup = data;
m_sel35_cb((m_setup >> 1) & 1);
logerror("setup write=%s %s nogcrconv=%s %s %s%s %s\n",
m_setup & 0x40 ? "gcr" : "mfm",
m_setup & 0x20 ? "ibm" : "apple",
m_setup & 0x10 ? "on" : "off",
m_setup & 0x08 ? "fclk/2" : "fclk",
m_setup & 0x04 ? "gcr" : "mfm",
m_setup & 0x02 ? " copy" : "",
m_setup & 0x01 ? "wrinvert" : "wrdirect");
break;
case 0x6: // mode clear
m_mode &= ~data;
show_mode();
break;
case 0x7: // mode set
m_mode |= data;
show_mode();
break;
case 0x9: // step
logerror("load step %02x\n", data);
m_step = data;
break;
case 0xc:
m_gap = data;
break;
case 0xd:
m_sect1 = data;
break;
case 0xe:
m_xfer = data;
break;
case 0xf:
m_imask = data;
logerror("imask%s%s%s%s%s\n",
m_imask & 0x10 ? " sense" : " -",
m_imask & 0x08 ? " sector" : " -",
m_imask & 0x04 ? " id" : " -",
m_imask & 0x02 ? " step" : " -",
m_imask & 0x01 ? " timer" : " -");
update_irq();
break;
default:
logerror("write %s, %02x\n", names[offset], data);
break;
}
if((m_mode ^ prev_mode) & 0x86)
m_devsel_cb((m_mode >> 1) & 3);
if((m_mode ^ prev_mode) & 0x20)
m_hdsel_cb((m_mode >> 5) & 1);
if((m_mode & 0x80) && m_state == S_IDLE) {
logerror("%s stepping start count=%02x floppy=%s\n", machine().time().to_string(), m_step, m_floppy ? m_floppy->tag() : "-");
m_state = S_STEP;
run(false, false);
}
if((m_mode & 0x08) && m_state == S_IDLE) {
logerror("%s read start %s %s s1=%02x xfer=%d floppy=%s\n", machine().time().to_string(), m_setup & 0x04 ? "gcr" : "mfm", m_setup & 0x08 ? "fclk/2" : "fclk", m_sect1, m_xfer, m_floppy ? m_floppy->tag() : "-");
m_state = S_ID;
run(false, false);
}
if(!(m_mode & 0x88) && m_state != S_IDLE) {
logerror("%s read/step stopped\n", machine().time().to_string());
m_drq_write = false;
live_abort();
m_state = S_IDLE;
}
}
void swim3_device::update_irq()
{
logerror("irq %02x m %02x -> %02x\n", m_irq, m_imask, m_irq & m_imask);
m_irq_cb((m_irq & m_imask) != 0);
}
void swim3_device::update_drq()
{
if(m_drq_write)
m_drq_cb(m_fifo_pos != 2);
else
m_drq_cb(m_fifo_pos != 0);
}
void swim3_device::index_callback(floppy_image_device *floppy, int state)
{
if(state) {
sync();
run(false, true);
}
}
TIMER_CALLBACK_MEMBER(swim3_device::update)
{
sync();
run(true, false);
}
void swim3_device::delay(int cycles)
{
m_timer->adjust(attotime::from_ticks(cycles, clock()));
}
void swim3_device::run(bool timeout, bool index)
{
for(;;) {
if(m_cur_live.state != L_IDLE) {
live_run();
if(m_cur_live.state != L_IDLE)
return;
}
switch(m_state) {
case S_IDLE:
return;
case S_STEP:
if(!m_step) {
m_state = S_STEP_DONE;
break;
}
m_phases ^= 8;
update_phases();
m_state = S_STEP_1;
delay(4);
break;
case S_STEP_1:
if(!timeout)
return;
m_phases ^= 8;
update_phases();
m_state = S_STEP_0;
delay(2502);
break;
case S_STEP_0:
if(!timeout)
return;
m_step --;
m_state = S_STEP;
break;
case S_STEP_DONE:
m_state = S_IDLE;
m_mode &= 0x7f;
m_irq |= 0x02;
update_irq();
break;
case S_ID:
live_start(m_setup & 0x04 ? L_GCR_SEARCH_ID : L_MFM_SEARCH_ID);
return;
}
}
}
void swim3_device::checkpoint()
{
m_cur_live.pll.commit(m_floppy, m_cur_live.tm);
m_checkpoint_live = m_cur_live;
}
void swim3_device::rollback()
{
m_cur_live = m_checkpoint_live;
}
void swim3_device::live_delay(int state)
{
m_cur_live.next_state = state;
m_timer->adjust(m_cur_live.tm - machine().time());
}
void swim3_device::sync()
{
if(m_cur_live.state != L_IDLE && !m_cur_live.tm.is_never()) {
if(m_cur_live.tm > machine().time()) {
if(0)
logerror("%s: Rolling back and replaying (%s)\n", machine().time().to_string(), m_cur_live.tm.to_string());
rollback();
live_run(machine().time());
m_cur_live.pll.commit(m_floppy, m_cur_live.tm);
} else {
if(0)
logerror("%s: Committing (%s)\n", machine().time().to_string(), m_cur_live.tm.to_string());
m_cur_live.pll.commit(m_floppy, m_cur_live.tm);
if(m_cur_live.next_state != -1) {
m_cur_live.state = m_cur_live.next_state;
m_cur_live.next_state = -1;
}
if(m_cur_live.state == L_IDLE) {
m_cur_live.pll.stop_writing(m_floppy, m_cur_live.tm);
m_cur_live.tm = attotime::never;
}
}
m_cur_live.next_state = -1;
checkpoint();
}
}
void swim3_device::live_abort()
{
if(!m_cur_live.tm.is_never() && m_cur_live.tm > machine().time()) {
rollback();
live_run(machine().time());
}
m_cur_live.pll.stop_writing(m_floppy, m_cur_live.tm);
m_cur_live.tm = attotime::never;
m_cur_live.state = L_IDLE;
m_cur_live.next_state = -1;
}
bool swim3_device::read_one_bit(const attotime &limit)
{
int bit = m_cur_live.pll.get_next_bit(m_cur_live.tm, m_floppy, limit);
if(bit < 0)
return true;
m_cur_live.shift_reg = (m_cur_live.shift_reg << 1) | bit;
m_cur_live.bit_counter++;
if(m_cur_live.data_separator_phase) {
m_cur_live.data_reg = (m_cur_live.data_reg << 1) | bit;
if((m_cur_live.crc ^ (bit ? 0x8000 : 0x0000)) & 0x8000)
m_cur_live.crc = (m_cur_live.crc << 1) ^ 0x1021;
else
m_cur_live.crc = m_cur_live.crc << 1;
}
m_cur_live.data_separator_phase = !m_cur_live.data_separator_phase;
return false;
}
bool swim3_device::write_one_bit(const attotime &limit)
{
bool bit = m_cur_live.shift_reg & 0x8000;
if(m_cur_live.pll.write_next_bit(bit, m_cur_live.tm, m_floppy, limit))
return true;
if(m_cur_live.bit_counter & 1) {
if((m_cur_live.crc ^ (bit ? 0x8000 : 0x0000)) & 0x8000)
m_cur_live.crc = (m_cur_live.crc << 1) ^ 0x1021;
else
m_cur_live.crc = m_cur_live.crc << 1;
}
m_cur_live.shift_reg = m_cur_live.shift_reg << 1;
m_cur_live.bit_counter--;
return false;
}
void swim3_device::live_start(int state, bool start_writing)
{
m_cur_live.tm = machine().time();
m_cur_live.state = state;
m_cur_live.next_state = -1;
m_cur_live.shift_reg = 0;
m_cur_live.crc = 0xffff;
m_cur_live.bit_counter = 0;
m_cur_live.data_separator_phase = false;
m_cur_live.data_reg = 0;
static const int cycles_per_cell[4] = { 16, 31, 31, 63 };
m_cur_live.pll.reset(m_cur_live.tm);
m_cur_live.pll.set_clock(attotime::from_ticks(cycles_per_cell[(m_setup >> 2) & 3], clock()));
if(start_writing)
m_cur_live.pll.start_writing(machine().time());
logerror("PLL %s clock %s\n", start_writing ? "write" : "read", attotime::from_ticks(cycles_per_cell[(m_setup >> 2) & 3], clock()).to_string());
m_checkpoint_live = m_cur_live;
live_run();
}
u8 swim3_device::dma_r()
{
if(m_fifo_pos == 0) {
m_error |= 0x04;
live_abort();
m_state = S_IDLE;
return 0;
}
u8 r = m_fifo[0];
m_fifo[0] = m_fifo[1];
m_fifo_pos--;
update_drq();
return r;
}
void swim3_device::fifo_push(u8 data)
{
if(m_fifo_pos == 2) {
m_error |= 0x01;
live_abort();
m_state = S_IDLE;
} else {
m_fifo[m_fifo_pos++] = data;
update_drq();
}
}
void swim3_device::live_run(attotime limit)
{
if(m_cur_live.state == L_IDLE || m_cur_live.next_state != -1)
return;
if(limit == attotime::never) {
if(m_floppy)
limit = m_floppy->time_next_index();
if(limit == attotime::never) {
// Happens when there's no disk or if the swim3 is not
// connected to a drive, hence no index pulse. Force a
// sync from time to time in that case, so that the main
// cpu timeout isn't too painful. Avoids looping into
// infinity looking for data too.
limit = machine().time() + attotime::from_msec(1);
m_timer->adjust(attotime::from_msec(1));
}
}
for(;;) {
switch(m_cur_live.state) {
case L_MFM_SEARCH_ID:
if(read_one_bit(limit))
return;
if((m_cur_live.bit_counter & 1) != (m_cur_live.shift_reg & 1)) {
if(m_cur_live.bit_counter < 64) {
m_cur_live.bit_counter = 0;
m_cur_live.data_separator_phase = false;
} else {
m_cur_live.bit_counter = 1;
m_cur_live.state = L_MFM_SCAN_ID;
break;
}
}
if(!(m_cur_live.bit_counter & 1))
m_cur_live.crc = 0xffff;
// logerror("pre counter %02d sr %04x data %02x crc %04x\n", m_cur_live.bit_counter, m_cur_live.shift_reg, m_cur_live.data_reg, m_cur_live.crc);
break;
case L_MFM_SCAN_ID:
if(read_one_bit(limit))
return;
if((m_cur_live.bit_counter == 16 || m_cur_live.bit_counter == 32 || m_cur_live.bit_counter == 48) && m_cur_live.shift_reg != 0x4489) {
m_cur_live.bit_counter = 0;
m_cur_live.state = L_MFM_SEARCH_ID;
break;
}
if(m_cur_live.bit_counter == 64 && m_cur_live.shift_reg != 0x5554) { // fe
m_cur_live.bit_counter = 0;
m_cur_live.state = L_MFM_SEARCH_ID;
break;
}
if(m_cur_live.bit_counter == 64) {
m_cur_live.bit_counter = 0;
live_delay(L_MFM_READ_ID);
return;
}
// logerror("post counter %02d sr %04x data %02x crc %04x\n", m_cur_live.bit_counter, m_cur_live.shift_reg, m_cur_live.data_reg, m_cur_live.crc);
break;
case L_MFM_READ_ID:
if(!m_cur_live.bit_counter)
m_cur_sector &= 0x7f;
if(read_one_bit(limit))
return;
if(!(m_cur_live.bit_counter & 0xf)) {
live_delay(L_MFM_READ_ID_BYTE);
return;
}
break;
case L_MFM_READ_ID_BYTE:
m_cur_live.state = L_MFM_READ_ID;
switch(m_cur_live.bit_counter >> 4) {
case 1:
m_cur_track = m_cur_live.data_reg & 0x7f;
break;
case 2:
m_cur_track |= (m_cur_live.data_reg & 1) << 7;
break;
case 3:
m_cur_sector = m_cur_live.data_reg & 0x3f;
break;
case 4:
m_cur_format = m_cur_live.data_reg;
break;
case 6:
m_cur_live.bit_counter = 0;
m_cur_live.state = L_MFM_SEARCH_ID;
if(m_cur_live.crc == 0) {
logerror("sector id found, track=%02d head=%d sector=%02d\n", m_cur_track & 0x7f, m_cur_track >> 7, m_cur_sector & 0x3f);
m_cur_sector |= 0x80;
m_irq |= 0x04;
update_irq();
if(!(m_sect1 & 0x80) && ((m_sect1 & 0x40) || (m_sect1 & 0x3f) == (m_cur_sector & 0x3f))) {
logerror("sector matches, reading data\n");
m_cur_live.state = L_MFM_SEARCH_DATA;
}
} else {
checkpoint();
m_error |= 0x40;
live_abort();
m_state = S_IDLE;
return;
}
checkpoint();
break;
}
break;
case L_MFM_SEARCH_DATA:
if(read_one_bit(limit))
return;
if((m_cur_live.bit_counter & 1) != (m_cur_live.shift_reg & 1)) {
if(m_cur_live.bit_counter < 64) {
m_cur_live.bit_counter = 0;
m_cur_live.data_separator_phase = false;
} else {
m_cur_live.bit_counter = 1;
m_cur_live.state = L_MFM_SCAN_DATA;
break;
}
}
if(!(m_cur_live.bit_counter & 1))
m_cur_live.crc = 0xffff;
// logerror("pre counter %02d sr %04x data %02x crc %04x\n", m_cur_live.bit_counter, m_cur_live.shift_reg, m_cur_live.data_reg, m_cur_live.crc);
break;
case L_MFM_SCAN_DATA:
if(read_one_bit(limit))
return;
if((m_cur_live.bit_counter == 16 || m_cur_live.bit_counter == 32 || m_cur_live.bit_counter == 48) && m_cur_live.shift_reg != 0x4489) {
m_cur_live.bit_counter = 0;
m_cur_live.state = L_MFM_SEARCH_DATA;
break;
}
if(m_cur_live.bit_counter == 64 && m_cur_live.shift_reg != 0x5545) { // fb
m_cur_live.bit_counter = 0;
m_cur_live.state = L_MFM_SEARCH_DATA;
break;
}
if(m_cur_live.bit_counter == 64) {
m_cur_live.bit_counter = 0;
live_delay(L_MFM_READ_DATA);
return;
}
// logerror("post counter %02d sr %04x data %02x crc %04x\n", m_cur_live.bit_counter, m_cur_live.shift_reg, m_cur_live.data_reg, m_cur_live.crc);
break;
case L_MFM_READ_DATA:
if(!m_cur_live.bit_counter)
m_cur_sector &= 0x7f;
if(read_one_bit(limit))
return;
if(!(m_cur_live.bit_counter & 0xf)) {
live_delay(L_MFM_READ_DATA_BYTE);
return;
}
break;
case L_MFM_READ_DATA_BYTE:
m_cur_live.state = L_MFM_READ_DATA;
if(m_cur_live.bit_counter <= 512*16) {
fifo_push(m_cur_live.data_reg);
if(m_error)
return;
}
if(m_cur_live.bit_counter == 514*16) {
if(m_cur_live.crc == 0) {
logerror("sector read done, crc ok\n");
m_xfer --;
if(m_xfer == 0) {
m_irq |= 0x08;
m_mode &= ~8;
live_abort();
m_state = S_IDLE;
update_irq();
return;
}
m_cur_live.state = L_MFM_SEARCH_DATA;
} else {
checkpoint();
m_error |= 0x80;
m_mode &= ~8;
live_abort();
m_state = S_IDLE;
return;
}
checkpoint();
break;
}
break;
case L_GCR_SEARCH_ID:
logerror("gcr search id\n");
exit(0);
}
}
}