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+// license:BSD-3-Clause
+// copyright-holders:Fabio Priuli
+/***********************************************************************************************************
+
+
+ NES/Famicom cartridge emulation for Disk System expansion
+
+
+ Here we emulate the RAM expansion + Disk Drive which form the
+ Famicom Disk System.
+
+ Based on info from NESDev wiki ( http://wiki.nesdev.com/w/index.php/Family_Computer_Disk_System )
+
+ TODO:
+ - convert floppy drive + fds format to modern code!
+ - add sound bits
+ - stop IRQ from using HOLD_LINE
+
+ ***********************************************************************************************************/
+
+
+#include "emu.h"
+#include "disksys.h"
+#include "cpu/m6502/m6502.h"
+#include "imagedev/flopdrv.h"
+#include "formats/nes_dsk.h"
+
+#ifdef NES_PCB_DEBUG
+ #define VERBOSE 1
+#else
+ #define VERBOSE 0
+#endif
+
+#define LOG_MMC(x) do { if (VERBOSE) logerror x; } while (0)
+
+
+//-----------------------------------------------
+//
+// Disk drive implementation
+//
+//-----------------------------------------------
+
+static const floppy_interface nes_floppy_interface =
+{
+ FLOPPY_STANDARD_5_25_DSHD,
+ LEGACY_FLOPPY_OPTIONS_NAME(nes_only),
+ "floppy_5_25"
+};
+
+static MACHINE_CONFIG_FRAGMENT( nes_disksys )
+ MCFG_LEGACY_FLOPPY_DRIVE_ADD(FLOPPY_0, nes_floppy_interface)
+MACHINE_CONFIG_END
+
+//-------------------------------------------------
+// machine_config_additions - device-specific
+// machine configurations
+//-------------------------------------------------
+
+machine_config_constructor nes_disksys_device::device_mconfig_additions() const
+{
+ return MACHINE_CONFIG_NAME( nes_disksys );
+}
+
+
+
+ROM_START( disksys )
+ ROM_REGION(0x2000, "drive", 0)
+ ROM_SYSTEM_BIOS( 0, "2c33a-01a", "Famicom Disk System Bios")
+ ROMX_LOAD( "rp2c33a-01a.bin", 0x0000, 0x2000, CRC(5e607dcf) SHA1(57fe1bdee955bb48d357e463ccbf129496930b62), ROM_BIOS(1)) // newer, Nintendo logo has no shadow
+ ROM_SYSTEM_BIOS( 1, "2c33-01", "Famicom Disk System Bios, older")
+ ROMX_LOAD( "rp2c33-01.bin", 0x0000, 0x2000, CRC(1c7ae5d5) SHA1(af5af53f66982e749643fdf8b2acbb7d4d3ed229), ROM_BIOS(2)) // older, Nintendo logo has shadow
+ROM_END
+
+//-------------------------------------------------
+// rom_region - device-specific ROM region
+//-------------------------------------------------
+
+const rom_entry *nes_disksys_device::device_rom_region() const
+{
+ return ROM_NAME( disksys );
+}
+
+
+void nes_disksys_device::load_proc(device_image_interface &image)
+{
+ nes_disksys_device *disk_sys = static_cast<nes_disksys_device *>(image.device().owner());
+ disk_sys->load_disk(image);
+}
+
+void nes_disksys_device::unload_proc(device_image_interface &image)
+{
+ nes_disksys_device *disk_sys = static_cast<nes_disksys_device *>(image.device().owner());
+ disk_sys->unload_disk(image);
+}
+
+
+//------------------------------------------------
+//
+// RAM expansion cart implementation
+//
+//------------------------------------------------
+
+const device_type NES_DISKSYS = &device_creator<nes_disksys_device>;
+
+
+nes_disksys_device::nes_disksys_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock)
+ : nes_nrom_device(mconfig, NES_DISKSYS, "FC RAM Expansion + Disk System PCB", tag, owner, clock, "fc_disksys", __FILE__),
+ m_fds_data(NULL),
+ m_disk(*this, FLOPPY_0),
+ m_fds_sides(0)
+{
+}
+
+
+void nes_disksys_device::device_start()
+{
+ common_start();
+
+ m_2c33_rom = (UINT8*)memregion("drive")->base();
+
+ m_disk->floppy_install_load_proc(nes_disksys_device::load_proc);
+ m_disk->floppy_install_unload_proc(nes_disksys_device::unload_proc);
+
+ irq_timer = timer_alloc(TIMER_IRQ);
+ irq_timer->adjust(attotime::zero, 0, machine().device<cpu_device>("maincpu")->cycles_to_attotime(1));
+
+ save_item(NAME(m_fds_motor_on));
+ save_item(NAME(m_fds_door_closed));
+ save_item(NAME(m_fds_current_side));
+ save_item(NAME(m_fds_head_position));
+ save_item(NAME(m_fds_status0));
+ save_item(NAME(m_read_mode));
+ save_item(NAME(m_drive_ready));
+ save_item(NAME(m_irq_enable));
+ save_item(NAME(m_irq_transfer));
+ save_item(NAME(m_irq_count));
+ save_item(NAME(m_irq_count_latch));
+
+ save_item(NAME(m_fds_last_side));
+ save_item(NAME(m_fds_count));
+}
+
+void nes_disksys_device::pcb_reset()
+{
+ // read accesses in 0x6000-0xffff are always handled by
+ // cutom code below, so no need to setup the prg...
+ chr8(0, CHRRAM);
+ set_nt_mirroring(PPU_MIRROR_VERT);
+
+ m_fds_motor_on = 0;
+ m_fds_door_closed = 0;
+ m_fds_current_side = 1;
+ m_fds_head_position = 0;
+ m_fds_status0 = 0;
+ m_read_mode = 0;
+ m_drive_ready = 0;
+ m_irq_count = 0;
+ m_irq_count_latch = 0;
+ m_irq_enable = 0;
+ m_irq_transfer = 0;
+
+ m_fds_count = 0;
+ m_fds_last_side = 0;
+}
+
+
+/*-------------------------------------------------
+ mapper specific handlers
+ -------------------------------------------------*/
+
+/*-------------------------------------------------
+
+ RAM is in 0x6000-0xdfff (32K)
+ ROM is in 0xe000-0xffff (8K)
+
+ registers + disk drive are accessed in
+ 0x4020-0x403f (read_ex/write_ex below)
+
+ -------------------------------------------------*/
+
+WRITE8_MEMBER(nes_disksys_device::write_h)
+{
+ LOG_MMC(("Famicom Disk System write_h, offset %04x, data: %02x\n", offset, data));
+
+ if (offset < 0x6000)
+ m_prgram[offset + 0x2000] = data;
+}
+
+READ8_MEMBER(nes_disksys_device::read_h)
+{
+ LOG_MMC(("Famicom Disk System read_h, offset: %04x\n", offset));
+
+ if (offset < 0x6000)
+ return m_prgram[offset + 0x2000];
+ else
+ return m_2c33_rom[offset & 0x1fff];
+}
+
+WRITE8_MEMBER(nes_disksys_device::write_m)
+{
+ LOG_MMC(("Famicom Disk System write_m, offset: %04x, data: %02x\n", offset, data));
+ m_prgram[offset] = data;
+}
+
+READ8_MEMBER(nes_disksys_device::read_m)
+{
+ LOG_MMC(("Famicom Disk System read_m, offset: %04x\n", offset));
+ return m_prgram[offset];
+}
+
+void nes_disksys_device::hblank_irq(int scanline, int vblank, int blanked)
+{
+ if (m_irq_transfer)
+ m_maincpu->set_input_line(M6502_IRQ_LINE, HOLD_LINE);
+}
+
+WRITE8_MEMBER(nes_disksys_device::write_ex)
+{
+ LOG_MMC(("Famicom Disk System write_ex, offset: %04x, data: %02x\n", offset, data));
+
+ if (offset >= 0x20 && offset < 0x60)
+ {
+ // wavetable
+ }
+
+ switch (offset)
+ {
+ case 0x00:
+ m_irq_count_latch = (m_irq_count_latch & 0xff00) | data;
+ break;
+ case 0x01:
+ m_irq_count_latch = (m_irq_count_latch & 0x00ff) | (data << 8);
+ break;
+ case 0x02:
+ m_irq_count = m_irq_count_latch;
+ m_irq_enable = BIT(data, 1);
+ break;
+ case 0x03:
+ // bit0 - Enable disk I/O registers
+ // bit1 - Enable sound I/O registers
+ break;
+ case 0x04:
+ // write data out to disk
+ // TEST!
+ if (m_fds_data && m_fds_current_side && !m_read_mode)
+ m_fds_data[(m_fds_current_side - 1) * 65500 + m_fds_head_position++] = data;
+ break;
+ case 0x05:
+ // $4025 - FDS Control
+ // bit0 - Drive Motor Control (0: Stop motor; 1: Turn on motor)
+ // bit1 - Transfer Reset (Set 1 to reset transfer timing to the initial state)
+ // bit2 - Read / Write mode (0: write; 1: read)
+ // bit3 - Mirroring (0: horizontal; 1: vertical)
+ // bit4 - CRC control (set during CRC calculation of transfer)
+ // bit5 - Always set to '1'
+ // bit6 - Read/Write Start (Set to 1 when the drive becomes ready for read/write)
+ // bit7 - Interrupt Transfer (0: Transfer without using IRQ; 1: Enable IRQ when
+ // the drive becomes ready)
+ m_fds_motor_on = BIT(data, 0);
+
+ if (BIT(data, 1))
+ m_fds_head_position = 0;
+
+ if (!(data & 0x40) && m_drive_ready && m_fds_head_position > 2)
+ m_fds_head_position -= 2; // ??? is this some sort of compensation??
+
+ m_read_mode = BIT(data, 2);
+ set_nt_mirroring(BIT(data, 3) ? PPU_MIRROR_HORZ : PPU_MIRROR_VERT);
+ m_drive_ready = data & 0x40;
+ m_irq_transfer = BIT(data, 7);
+ break;
+ case 0x06:
+ // external connector
+ break;
+ case 0x60: // $4080 - Volume envelope - read through $4090
+ case 0x62: // $4082 - Frequency low
+ case 0x63: // $4083 - Frequency high
+ case 0x64: // $4084 - Mod envelope - read through $4092
+ case 0x65: // $4085 - Mod counter
+ case 0x66: // $4086 - Mod frequency low
+ case 0x67: // $4087 - Mod frequency high
+ case 0x68: // $4088 - Mod table write
+ case 0x69: // $4089 - Wave write / master volume
+ case 0x6a: // $408a - Envelope speed
+ break;
+ }
+}
+
+READ8_MEMBER(nes_disksys_device::read_ex)
+{
+ LOG_MMC(("Famicom Disk System read_ex, offset: %04x\n", offset));
+ UINT8 ret = 0x00;
+
+ if (offset >= 0x20 && offset < 0x60)
+ {
+ // wavetable
+ }
+
+ switch (offset)
+ {
+ case 0x10:
+ // $4030 - disk status 0
+ // bit0 - Timer Interrupt (1: an IRQ occurred)
+ // bit1 - Byte transfer flag (Set to 1 every time 8 bits have been transfered between
+ // the RAM adaptor & disk drive through $4024/$4031; Reset to 0 when $4024,
+ // $4031, or $4030 has been serviced)
+ // bit4 - CRC control (0: CRC passed; 1: CRC error)
+ // bit6 - End of Head (1 when disk head is on the most inner track)
+ // bit7 - Disk Data Read/Write Enable (1 when disk is readable/writable)
+ ret = m_fds_status0 | 0x80;
+ // clear the disk IRQ detect flag
+ m_fds_status0 &= ~0x01;
+ break;
+ case 0x11:
+ // $4031 - data latch
+ // don't read data if disk is unloaded
+ if (!m_fds_data)
+ ret = 0;
+ else if (m_fds_current_side && m_read_mode)
+ {
+ ret = m_fds_data[(m_fds_current_side - 1) * 65500 + m_fds_head_position++];
+ if (m_fds_head_position == 65500)
+ {
+ printf("end of disk reached!\n");
+ m_fds_status0 |= 0x40;
+ m_fds_head_position -= 2;
+ }
+ }
+ else
+ ret = 0;
+ break;
+ case 0x12:
+ // $4032 - disk status 1:
+ // bit0 - Disk flag (0: Disk inserted; 1: Disk not inserted)
+ // bit1 - Ready flag (0: Disk ready; 1: Disk not ready)
+ // bit2 - Protect flag (0: Not write protected; 1: Write protected or disk ejected)
+ if (!m_fds_data)
+ ret = 1;
+ else if (m_fds_last_side != m_fds_current_side)
+ {
+ // If we've switched disks, report "no disk" for a few reads
+ ret = 1;
+ m_fds_count++;
+ if (m_fds_count == 50)
+ {
+ m_fds_last_side = m_fds_current_side;
+ m_fds_count = 0;
+ }
+ }
+ else
+ ret = (m_fds_current_side == 0) ? 1 : 0; // 0 if a disk is inserted
+ break;
+ case 0x13:
+ // $4033 - external connector (bits 0-6) + battery status (bit 7)
+ ret = 0x80;
+ break;
+ case 0x70: // $4090 - Volume gain - write through $4080
+ case 0x72: // $4092 - Mod gain - read through $4084
+ default:
+ ret = 0x00;
+ break;
+ }
+
+ return ret;
+}
+
+//-------------------------------------------------
+// device_timer - handler timer events
+//-------------------------------------------------
+
+void nes_disksys_device::device_timer(emu_timer &timer, device_timer_id id, int param, void *ptr)
+{
+ if (id == TIMER_IRQ)
+ {
+ if (m_irq_enable && m_irq_count)
+ {
+ m_irq_count--;
+ if (!m_irq_count)
+ {
+ m_maincpu->set_input_line(M6502_IRQ_LINE, HOLD_LINE);
+ m_irq_enable = 0;
+ m_fds_status0 |= 0x01;
+ m_irq_count_latch = 0; // used in Kaettekita Mario Bros
+ }
+ }
+ }
+}
+
+
+// Hacky helper to allow user to switch disk side with a simple key
+
+void nes_disksys_device::disk_flip_side()
+{
+ m_fds_current_side++;
+ if (m_fds_current_side > m_fds_sides)
+ m_fds_current_side = 0;
+
+ if (m_fds_current_side == 0)
+ popmessage("No disk inserted.");
+ else
+ popmessage("Disk set to side %d", m_fds_current_side);
+}
+
+
+
+// Disk Loading / Unloading
+
+void nes_disksys_device::load_disk(device_image_interface &image)
+{
+ int header = 0;
+ m_fds_sides = 0;
+
+ if (image.length() % 65500)
+ header = 0x10;
+
+ m_fds_sides = (image.length() - header) / 65500;
+
+ if (!m_fds_data)
+ m_fds_data = auto_alloc_array(machine(), UINT8, m_fds_sides * 65500);
+
+ // if there is an header, skip it
+ image.fseek(header, SEEK_SET);
+ image.fread(m_fds_data, 65500 * m_fds_sides);
+ return;
+}
+
+void nes_disksys_device::unload_disk(device_image_interface &image)
+{
+ /* TODO: should write out changes here as well */
+ m_fds_sides = 0;
+}