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author | 2015-09-13 08:41:44 +0200 | |
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committer | 2015-09-13 08:41:44 +0200 | |
commit | f88cefad27a1737c76e09d99c9fb43e173506081 (patch) | |
tree | 2d8167d03579c46e226471747eb4407bd00ed6fa /src/devices/bus/ieee488/c2040fdc.c | |
parent | e92ac9e0fa8e99869894bea00589bbb526be30aa (diff) |
Move all devices into separate part of src tree (nw)
Diffstat (limited to 'src/devices/bus/ieee488/c2040fdc.c')
-rw-r--r-- | src/devices/bus/ieee488/c2040fdc.c | 623 |
1 files changed, 623 insertions, 0 deletions
diff --git a/src/devices/bus/ieee488/c2040fdc.c b/src/devices/bus/ieee488/c2040fdc.c new file mode 100644 index 00000000000..4dfccbde366 --- /dev/null +++ b/src/devices/bus/ieee488/c2040fdc.c @@ -0,0 +1,623 @@ +// license:BSD-3-Clause +// copyright-holders:Curt Coder +/********************************************************************** + + Commodore 2040 floppy disk controller emulation + +**********************************************************************/ + +/* + + TODO: + + - write protect + - separate read/write methods + +*/ + +#include "c2040fdc.h" + + + +//************************************************************************** +// MACROS / CONSTANTS +//************************************************************************** + +#define LOG 0 + +#define GCR_DECODE(_e, _i) \ + ((BIT(_e, 6) << 7) | (BIT(_i, 7) << 6) | (_e & 0x33) | (BIT(_e, 2) << 3) | (_i & 0x04)) + +#define GCR_ENCODE(_e, _i) \ + ((_e & 0xc0) << 2 | (_i & 0x80) | (_e & 0x3c) << 1 | (_i & 0x04) | (_e & 0x03)) + + + +//************************************************************************** +// DEVICE DEFINITIONS +//************************************************************************** + +const device_type C2040_FDC = &device_creator<c2040_fdc_t>; + + +//------------------------------------------------- +// ROM( c2040_fdc ) +//------------------------------------------------- + +ROM_START( c2040_fdc ) + ROM_REGION( 0x800, "gcr", 0) + ROM_LOAD( "901467.uk6", 0x000, 0x800, CRC(a23337eb) SHA1(97df576397608455616331f8e837cb3404363fa2) ) +ROM_END + + +//------------------------------------------------- +// rom_region - device-specific ROM region +//------------------------------------------------- + +const rom_entry *c2040_fdc_t::device_rom_region() const +{ + return ROM_NAME( c2040_fdc ); +} + + + +//************************************************************************** +// LIVE DEVICE +//************************************************************************** + +//------------------------------------------------- +// c2040_fdc_t - constructor +//------------------------------------------------- + +c2040_fdc_t::c2040_fdc_t(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock) : + device_t(mconfig, C2040_FDC, "C2040 FDC", tag, owner, clock, "c2040fdc", __FILE__), + m_write_sync(*this), + m_write_ready(*this), + m_write_error(*this), + m_gcr_rom(*this, "gcr"), + m_floppy0(NULL), + m_floppy1(NULL), + m_mtr0(1), + m_mtr1(1), + m_stp0(0), + m_stp1(0), + m_ds(0), + m_ds0(0), + m_ds1(0), + m_drv_sel(0), + m_mode_sel(0), + m_rw_sel(0), + m_period(attotime::from_hz(clock)) +{ + cur_live.tm = attotime::never; + cur_live.state = IDLE; + cur_live.next_state = -1; + cur_live.write_position = 0; + cur_live.write_start_time = attotime::never; + cur_live.drv_sel = m_drv_sel; +} + + +//------------------------------------------------- +// device_start - device-specific startup +//------------------------------------------------- + +void c2040_fdc_t::device_start() +{ + // resolve callbacks + m_write_sync.resolve_safe(); + m_write_ready.resolve_safe(); + m_write_error.resolve_safe(); + + // allocate timer + t_gen = timer_alloc(0); + + // register for state saving + save_item(NAME(m_mtr0)); + save_item(NAME(m_mtr1)); + save_item(NAME(m_stp0)); + save_item(NAME(m_stp1)); + save_item(NAME(m_ds)); + save_item(NAME(m_ds0)); + save_item(NAME(m_ds1)); + save_item(NAME(m_drv_sel)); + save_item(NAME(m_mode_sel)); + save_item(NAME(m_rw_sel)); +} + + +//------------------------------------------------- +// device_reset - device-specific reset +//------------------------------------------------- + +void c2040_fdc_t::device_reset() +{ + live_abort(); +} + + +//------------------------------------------------- +// device_timer - handler timer events +//------------------------------------------------- + +void c2040_fdc_t::device_timer(emu_timer &timer, device_timer_id id, int param, void *ptr) +{ + live_sync(); + live_run(); +} + +floppy_image_device* c2040_fdc_t::get_floppy() +{ + return cur_live.drv_sel ? m_floppy1 : m_floppy0; +} + +void c2040_fdc_t::live_start() +{ + cur_live.tm = machine().time(); + cur_live.state = RUNNING; + cur_live.next_state = -1; + + cur_live.shift_reg = 0; + cur_live.shift_reg_write = 0; + cur_live.cycle_counter = 0; + cur_live.cell_counter = 0; + cur_live.bit_counter = 0; + cur_live.ds = m_ds; + cur_live.drv_sel = m_drv_sel; + cur_live.mode_sel = m_mode_sel; + cur_live.rw_sel = m_rw_sel; + cur_live.pi = m_pi; + + checkpoint_live = cur_live; + + live_run(); +} + +void c2040_fdc_t::checkpoint() +{ + get_next_edge(machine().time()); + checkpoint_live = cur_live; +} + +void c2040_fdc_t::rollback() +{ + cur_live = checkpoint_live; + get_next_edge(cur_live.tm); +} + +void c2040_fdc_t::start_writing(const attotime &tm) +{ + cur_live.write_start_time = tm; + cur_live.write_position = 0; +} + +void c2040_fdc_t::stop_writing(const attotime &tm) +{ + commit(tm); + cur_live.write_start_time = attotime::never; +} + +bool c2040_fdc_t::write_next_bit(bool bit, const attotime &limit) +{ + if(cur_live.write_start_time.is_never()) { + cur_live.write_start_time = cur_live.tm; + cur_live.write_position = 0; + } + + attotime etime = cur_live.tm + m_period; + if(etime > limit) + return true; + + if(bit && cur_live.write_position < ARRAY_LENGTH(cur_live.write_buffer)) + cur_live.write_buffer[cur_live.write_position++] = cur_live.tm - m_period; + + if (LOG) logerror("%s write bit %u (%u)\n", cur_live.tm.as_string(), cur_live.bit_counter, bit); + + return false; +} + +void c2040_fdc_t::commit(const attotime &tm) +{ + if(cur_live.write_start_time.is_never() || tm == cur_live.write_start_time || !cur_live.write_position) + return; + + if (LOG) logerror("%s committing %u transitions since %s\n", tm.as_string(), cur_live.write_position, cur_live.write_start_time.as_string()); + + if(get_floppy()) + get_floppy()->write_flux(cur_live.write_start_time, tm, cur_live.write_position, cur_live.write_buffer); + + cur_live.write_start_time = tm; + cur_live.write_position = 0; +} + +void c2040_fdc_t::live_delay(int state) +{ + cur_live.next_state = state; + if(cur_live.tm != machine().time()) + t_gen->adjust(cur_live.tm - machine().time()); + else + live_sync(); +} + +void c2040_fdc_t::live_sync() +{ + if(!cur_live.tm.is_never()) { + if(cur_live.tm > machine().time()) { + rollback(); + live_run(machine().time()); + commit(cur_live.tm); + } else { + commit(cur_live.tm); + if(cur_live.next_state != -1) { + cur_live.state = cur_live.next_state; + cur_live.next_state = -1; + } + if(cur_live.state == IDLE) { + stop_writing(cur_live.tm); + cur_live.tm = attotime::never; + } + } + cur_live.next_state = -1; + checkpoint(); + } +} + +void c2040_fdc_t::live_abort() +{ + if(!cur_live.tm.is_never() && cur_live.tm > machine().time()) { + rollback(); + live_run(machine().time()); + } + + stop_writing(cur_live.tm); + + cur_live.tm = attotime::never; + cur_live.state = IDLE; + cur_live.next_state = -1; + cur_live.write_position = 0; + cur_live.write_start_time = attotime::never; + + cur_live.ready = 1; + cur_live.sync = 1; + cur_live.error = 1; +} + +void c2040_fdc_t::live_run(const attotime &limit) +{ + if(cur_live.state == IDLE || cur_live.next_state != -1) + return; + + for(;;) { + switch(cur_live.state) { + case RUNNING: { + bool syncpoint = false; + + if (cur_live.tm > limit) + return; + + int bit = get_next_bit(cur_live.tm, limit); + if(bit < 0) + return; + + int cell_counter = cur_live.cell_counter; + + if (bit) { + cur_live.cycle_counter = cur_live.ds; + cur_live.cell_counter = 0; + } else { + cur_live.cycle_counter++; + } + + if (cur_live.cycle_counter == 16) { + cur_live.cycle_counter = cur_live.ds; + + cur_live.cell_counter++; + cur_live.cell_counter &= 0xf; + } + + if (!BIT(cell_counter, 1) && BIT(cur_live.cell_counter, 1)) { + // read bit + cur_live.shift_reg <<= 1; + cur_live.shift_reg |= !(BIT(cur_live.cell_counter, 3) || BIT(cur_live.cell_counter, 2)); + cur_live.shift_reg &= 0x3ff; + + if (LOG) logerror("%s read bit %u (%u) >> %03x, rw=%u mode=%u\n", cur_live.tm.as_string(), cur_live.bit_counter, + !(BIT(cur_live.cell_counter, 3) || BIT(cur_live.cell_counter, 2)), cur_live.shift_reg, cur_live.rw_sel, cur_live.mode_sel); + + // write bit + if (!cur_live.rw_sel) { // TODO WPS + write_next_bit(BIT(cur_live.shift_reg_write, 9), limit); + } + + syncpoint = true; + } + + int sync = !((cur_live.shift_reg == 0x3ff) && cur_live.rw_sel); + + if (!sync) { + cur_live.bit_counter = 0; + } else if (!BIT(cell_counter, 1) && BIT(cur_live.cell_counter, 1) && cur_live.sync) { + cur_live.bit_counter++; + if (cur_live.bit_counter == 10) { + cur_live.bit_counter = 0; + } + } + + // update GCR + if (cur_live.rw_sel) { + cur_live.i = (cur_live.rw_sel << 10) | cur_live.shift_reg; + } else { + cur_live.i = (cur_live.rw_sel << 10) | ((cur_live.pi & 0xf0) << 1) | (cur_live.mode_sel << 4) | (cur_live.pi & 0x0f); + } + + cur_live.e = m_gcr_rom->base()[cur_live.i]; + + int ready = !(BIT(cell_counter, 1) && !BIT(cur_live.cell_counter, 1) && (cur_live.bit_counter == 9)); + + if (!ready) { + // load write shift register + cur_live.shift_reg_write = GCR_ENCODE(cur_live.e, cur_live.i); + + if (LOG) logerror("%s load write shift register %03x\n",cur_live.tm.as_string(),cur_live.shift_reg_write); + } else if (BIT(cell_counter, 1) && !BIT(cur_live.cell_counter, 1)) { + // clock write shift register + cur_live.shift_reg_write <<= 1; + cur_live.shift_reg_write &= 0x3ff; + + if (LOG) logerror("%s write shift << %03x\n",cur_live.tm.as_string(),cur_live.shift_reg_write); + } + + int error = !(BIT(cur_live.e, 3) || ready); + + if (ready != cur_live.ready) { + if (LOG) logerror("%s READY %u\n", cur_live.tm.as_string(),ready); + cur_live.ready = ready; + syncpoint = true; + } + + if (sync != cur_live.sync) { + if (LOG) logerror("%s SYNC %u\n", cur_live.tm.as_string(),sync); + cur_live.sync = sync; + syncpoint = true; + } + + if (error != cur_live.error) { + cur_live.error = error; + syncpoint = true; + } + + if (syncpoint) { + commit(cur_live.tm); + + cur_live.tm += m_period; + live_delay(RUNNING_SYNCPOINT); + return; + } + + cur_live.tm += m_period; + break; + } + + case RUNNING_SYNCPOINT: { + m_write_ready(cur_live.ready); + m_write_sync(cur_live.sync); + m_write_error(cur_live.error); + + cur_live.state = RUNNING; + checkpoint(); + break; + } + } + } +} + +void c2040_fdc_t::get_next_edge(const attotime &when) +{ + floppy_image_device *floppy = get_floppy(); + + cur_live.edge = floppy ? floppy->get_next_transition(when) : attotime::never; +} + +int c2040_fdc_t::get_next_bit(attotime &tm, const attotime &limit) +{ + attotime next = tm + m_period; + + int bit = (cur_live.edge.is_never() || cur_live.edge >= next) ? 0 : 1; + + if (bit) { + get_next_edge(next); + } + + return bit && cur_live.rw_sel; +} + +READ8_MEMBER( c2040_fdc_t::read ) +{ + UINT8 e = checkpoint_live.e; + offs_t i = checkpoint_live.i; + + UINT8 data = GCR_DECODE(e, i); + + if (LOG) logerror("%s %s VIA reads data %02x (%03x)\n", machine().time().as_string(), machine().describe_context(), data, checkpoint_live.shift_reg); + + return data; +} + +WRITE8_MEMBER( c2040_fdc_t::write ) +{ + if (m_pi != data) + { + live_sync(); + m_pi = cur_live.pi = data; + checkpoint(); + if (LOG) logerror("%s %s PI %02x\n", machine().time().as_string(), machine().describe_context(), data); + live_run(); + } +} + +WRITE_LINE_MEMBER( c2040_fdc_t::ds0_w ) +{ + m_ds0 = state; +} + +WRITE_LINE_MEMBER( c2040_fdc_t::ds1_w ) +{ + m_ds1 = state; + + ds_w(m_ds1 << 1 | m_ds0); +} + +WRITE_LINE_MEMBER( c2040_fdc_t::drv_sel_w ) +{ + if (m_drv_sel != state) + { + live_sync(); + m_drv_sel = cur_live.drv_sel = state; + checkpoint(); + if (LOG) logerror("%s %s DRV SEL %u\n", machine().time().as_string(), machine().describe_context(), state); + live_run(); + } +} + +WRITE_LINE_MEMBER( c2040_fdc_t::mode_sel_w ) +{ + if (m_mode_sel != state) + { + live_sync(); + m_mode_sel = cur_live.mode_sel = state; + checkpoint(); + if (LOG) logerror("%s %s MODE SEL %u\n", machine().time().as_string(), machine().describe_context(), state); + live_run(); + } +} + +WRITE_LINE_MEMBER( c2040_fdc_t::rw_sel_w ) +{ + if (m_rw_sel != state) + { + live_sync(); + m_rw_sel = cur_live.rw_sel = state; + checkpoint(); + if (LOG) logerror("%s %s RW SEL %u\n", machine().time().as_string(), machine().describe_context(), state); + if (m_rw_sel) { + stop_writing(machine().time()); + } else { + start_writing(machine().time()); + } + live_run(); + } +} + +WRITE_LINE_MEMBER( c2040_fdc_t::mtr0_w ) +{ + if (m_mtr0 != state) + { + live_sync(); + m_mtr0 = state; + if (LOG) logerror("%s %s MTR0 %u\n", machine().time().as_string(), machine().describe_context(), state); + m_floppy0->mon_w(state); + checkpoint(); + + if (!m_mtr0 || !m_mtr1) { + if(cur_live.state == IDLE) { + live_start(); + } + } else { + live_abort(); + } + + live_run(); + } +} + +WRITE_LINE_MEMBER( c2040_fdc_t::mtr1_w ) +{ + if (m_mtr1 != state) + { + live_sync(); + m_mtr1 = state; + if (LOG) logerror("%s %s MTR1 %u\n", machine().time().as_string(), machine().describe_context(), state); + if (m_floppy1) m_floppy1->mon_w(state); + checkpoint(); + + if (!m_mtr0 || !m_mtr1) { + if(cur_live.state == IDLE) { + live_start(); + } + } else { + live_abort(); + } + + live_run(); + } +} + +void c2040_fdc_t::stp_w(floppy_image_device *floppy, int mtr, int &old_stp, int stp) +{ + if (mtr) return; + + int tracks = 0; + + switch (old_stp) + { + case 0: if (stp == 1) tracks++; else if (stp == 3) tracks--; break; + case 1: if (stp == 2) tracks++; else if (stp == 0) tracks--; break; + case 2: if (stp == 3) tracks++; else if (stp == 1) tracks--; break; + case 3: if (stp == 0) tracks++; else if (stp == 2) tracks--; break; + } + + if (tracks == -1) + { + floppy->dir_w(1); + floppy->stp_w(1); + floppy->stp_w(0); + } + else if (tracks == 1) + { + floppy->dir_w(0); + floppy->stp_w(1); + floppy->stp_w(0); + } + + old_stp = stp; +} + +void c2040_fdc_t::stp0_w(int stp) +{ + if (m_stp0 != stp) + { + live_sync(); + this->stp_w(m_floppy0, m_mtr0, m_stp0, stp); + checkpoint(); + live_run(); + } +} + +void c2040_fdc_t::stp1_w(int stp) +{ + if (m_stp1 != stp) + { + live_sync(); + if (m_floppy1) this->stp_w(m_floppy1, m_mtr1, m_stp1, stp); + checkpoint(); + live_run(); + } +} + +void c2040_fdc_t::ds_w(int ds) +{ + if (m_ds != ds) + { + live_sync(); + m_ds = cur_live.ds = ds; + if (LOG) logerror("%s %s DS %u\n", machine().time().as_string(), machine().describe_context(), ds); + checkpoint(); + live_run(); + } +} + +void c2040_fdc_t::set_floppy(floppy_image_device *floppy0, floppy_image_device *floppy1) +{ + m_floppy0 = floppy0; + m_floppy1 = floppy1; +} |