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https://github.com/holub/mame
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af846ce015
This is an attempt to make how the various signals on the CoCo cartridge slot (CART, NMI, HALT) a bit more standardized and less ad hoc, especially with the practice of Program Paks tying the CART line to Q. This should fix some outstanding bugs in how these signals were passed around when using the CoCo Multi-Pak interface.
370 lines
13 KiB
C++
370 lines
13 KiB
C++
// license:BSD-3-Clause
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// copyright-holders:Nathan Woods
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/***************************************************************************
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coco_multi.cpp
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Code for emulating CoCo's Multi-Pak Interface
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The Multi-Pak interface multiplexes all I/O lines from the Color
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Computer's expansion port to four identical ports. All I/O lines
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are continuously multiplexed except:
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Pin 36 - *SCS
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Pin 32 - *CTS
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Pin 8 - *CART
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These I/O lines are switched in one of two ways. First, is the front
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panel, four position switch. When adjusted the switch will direct the
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MPI to target these three I/O lines to the selected slot.
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Second, the MPI will listen to writes to $FF7F and respond accordingly:
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bit 0 --\___ Target *SCS to this slot number
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bit 1 --/
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bit 2 ------ Ignore
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bit 3 ------ Ignore
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bit 4 --\___ Target *CTS and *CART to this slot number
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bit 5 --/
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bit 6 ------ Ignore
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bit 7 ------ Ignore
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After writing to $FF7F, the position of the physical switch has no
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effect until reset.
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Reading is supported on $FF7F. It will reflect the position of the
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physical switch. Until data is written to $FF7F, then it will only
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reflect what has been written until a reset.
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A common modification users of the OS-9 operating system made was to
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tie all of the *CART pins together on the MPI motherboard. The *CART
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line is connected to the 6809's IRQ line. This allowed any hardware
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device in any slot to signal an IRQ to the CPU, no matter what the
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switch position was. OS-9 was designed from the very start to poll
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each device attached on every IRQ signal.
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Because of sloppy address decoding the original MPI also responds to
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$FF9F. No software is known to take advantage of this. After the
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introduction of the CoCo 3, which uses $FF9F internally, Tandy provided
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free upgrades to any MPI to fix this problem. This behavior is not
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emulated (yet).
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Slots seem to be one-counted (i.e. - 1-4, not 0-3) by convention
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***************************************************************************/
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#include "emu.h"
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#include "coco_multi.h"
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#include "coco_232.h"
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#include "coco_orch90.h"
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#include "coco_pak.h"
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#include "coco_fdc.h"
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#define SLOT1_TAG "slot1"
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#define SLOT2_TAG "slot2"
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#define SLOT3_TAG "slot3"
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#define SLOT4_TAG "slot4"
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/***************************************************************************
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IMPLEMENTATION
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***************************************************************************/
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static SLOT_INTERFACE_START(coco_cart_slot1_3)
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SLOT_INTERFACE("rs232", COCO_232)
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SLOT_INTERFACE("orch90", COCO_ORCH90)
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SLOT_INTERFACE("banked_16k", COCO_PAK_BANKED)
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SLOT_INTERFACE("pak", COCO_PAK)
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SLOT_INTERFACE_END
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static SLOT_INTERFACE_START(coco_cart_slot4)
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SLOT_INTERFACE("cc3hdb1", COCO3_HDB1)
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SLOT_INTERFACE("fdcv11", COCO_FDC_V11)
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SLOT_INTERFACE("rs232", COCO_232)
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SLOT_INTERFACE("orch90", COCO_ORCH90)
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SLOT_INTERFACE("banked_16k", COCO_PAK_BANKED)
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SLOT_INTERFACE("pak", COCO_PAK)
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SLOT_INTERFACE_END
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static MACHINE_CONFIG_FRAGMENT(coco_multi)
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MCFG_COCO_CARTRIDGE_ADD(SLOT1_TAG, coco_cart_slot1_3, nullptr)
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MCFG_COCO_CARTRIDGE_CART_CB(DEVWRITELINE(DEVICE_SELF, coco_multipak_device, multi_slot1_cart_w))
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MCFG_COCO_CARTRIDGE_NMI_CB(DEVWRITELINE(DEVICE_SELF, coco_multipak_device, multi_slot1_nmi_w))
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MCFG_COCO_CARTRIDGE_HALT_CB(DEVWRITELINE(DEVICE_SELF, coco_multipak_device, multi_slot1_halt_w))
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MCFG_COCO_CARTRIDGE_ADD(SLOT2_TAG, coco_cart_slot1_3, nullptr)
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MCFG_COCO_CARTRIDGE_CART_CB(DEVWRITELINE(DEVICE_SELF, coco_multipak_device, multi_slot2_cart_w))
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MCFG_COCO_CARTRIDGE_NMI_CB(DEVWRITELINE(DEVICE_SELF, coco_multipak_device, multi_slot2_nmi_w))
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MCFG_COCO_CARTRIDGE_HALT_CB(DEVWRITELINE(DEVICE_SELF, coco_multipak_device, multi_slot2_halt_w))
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MCFG_COCO_CARTRIDGE_ADD(SLOT3_TAG, coco_cart_slot1_3, nullptr)
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MCFG_COCO_CARTRIDGE_CART_CB(DEVWRITELINE(DEVICE_SELF, coco_multipak_device, multi_slot3_cart_w))
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MCFG_COCO_CARTRIDGE_NMI_CB(DEVWRITELINE(DEVICE_SELF, coco_multipak_device, multi_slot3_nmi_w))
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MCFG_COCO_CARTRIDGE_HALT_CB(DEVWRITELINE(DEVICE_SELF, coco_multipak_device, multi_slot3_halt_w))
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MCFG_COCO_CARTRIDGE_ADD(SLOT4_TAG, coco_cart_slot4, "fdcv11")
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MCFG_COCO_CARTRIDGE_CART_CB(DEVWRITELINE(DEVICE_SELF, coco_multipak_device, multi_slot4_cart_w))
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MCFG_COCO_CARTRIDGE_NMI_CB(DEVWRITELINE(DEVICE_SELF, coco_multipak_device, multi_slot4_nmi_w))
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MCFG_COCO_CARTRIDGE_HALT_CB(DEVWRITELINE(DEVICE_SELF, coco_multipak_device, multi_slot4_halt_w))
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MACHINE_CONFIG_END
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//**************************************************************************
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// GLOBAL VARIABLES
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//**************************************************************************
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const device_type COCO_MULTIPAK = device_creator<coco_multipak_device>;
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//**************************************************************************
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// LIVE DEVICE
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//**************************************************************************
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//-------------------------------------------------
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// coco_multipak_device - constructor
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//-------------------------------------------------
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coco_multipak_device::coco_multipak_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
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: device_t(mconfig, COCO_MULTIPAK, "CoCo Multi-Pak Interface", tag, owner, clock, "coco_multipak", __FILE__),
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device_cococart_interface( mconfig, *this ), m_select(0)
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{
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}
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//-------------------------------------------------
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// device_start - device-specific startup
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//-------------------------------------------------
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void coco_multipak_device::device_start()
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{
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// identify slots
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m_slots[0] = dynamic_cast<cococart_slot_device *>(subdevice(SLOT1_TAG));
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m_slots[1] = dynamic_cast<cococart_slot_device *>(subdevice(SLOT2_TAG));
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m_slots[2] = dynamic_cast<cococart_slot_device *>(subdevice(SLOT3_TAG));
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m_slots[3] = dynamic_cast<cococart_slot_device *>(subdevice(SLOT4_TAG));
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// install $FF7F handler
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write8_delegate wh = write8_delegate(FUNC(coco_multipak_device::ff7f_write), this);
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machine().device(":maincpu")->memory().space(AS_PROGRAM).install_write_handler(0xFF7F, 0xFF7F, wh);
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// initial state
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m_select = 0xFF;
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// save state
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save_item(NAME(m_select));
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}
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//-------------------------------------------------
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// device_reset - device-specific reset
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//-------------------------------------------------
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void coco_multipak_device::device_reset()
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{
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m_select = 0xFF;
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}
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//-------------------------------------------------
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// machine_config_additions - device-specific
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// machine configurations
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//-------------------------------------------------
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machine_config_constructor coco_multipak_device::device_mconfig_additions() const
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{
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return MACHINE_CONFIG_NAME( coco_multi );
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}
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//**************************************************************************
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// INTERNAL ACCESSORS
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//**************************************************************************
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cococart_slot_device &coco_multipak_device::owning_slot()
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{
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return *dynamic_cast<cococart_slot_device *>(owner());
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}
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//-------------------------------------------------
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// active_scs_slot_number
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//-------------------------------------------------
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int coco_multipak_device::active_scs_slot_number() const
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{
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return ((m_select >> 0) & 0x03) + 1;
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}
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//-------------------------------------------------
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// active_cts_slot_number
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//-------------------------------------------------
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int coco_multipak_device::active_cts_slot_number() const
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{
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return ((m_select >> 4) & 0x03) + 1;
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}
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//-------------------------------------------------
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// slot
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//-------------------------------------------------
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cococart_slot_device &coco_multipak_device::slot(int slot_number)
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{
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assert(slot_number >= 1 && slot_number <= 4);
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return *m_slots[slot_number - 1];
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}
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//-------------------------------------------------
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// active_scs_slot
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//-------------------------------------------------
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cococart_slot_device &coco_multipak_device::active_scs_slot()
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{
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int slot_number = active_scs_slot_number();
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return slot(slot_number);
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}
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//-------------------------------------------------
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// active_cts_slot
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//-------------------------------------------------
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cococart_slot_device &coco_multipak_device::active_cts_slot()
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{
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int slot_number = active_cts_slot_number();
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return slot(slot_number);
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}
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//**************************************************************************
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// METHODS
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//**************************************************************************
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//-------------------------------------------------
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// set_select
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//-------------------------------------------------
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void coco_multipak_device::set_select(uint8_t new_select)
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{
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// identify old value for CART, in case this needs to change
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cococart_slot_device::line_value old_cart = active_cts_slot().get_line_value(cococart_slot_device::line::CART);
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// change value
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uint8_t xorval = m_select ^ new_select;
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m_select = new_select;
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// did the cartridge base change?
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if (xorval & 0x03)
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cart_base_changed();
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// did the CART line change?
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cococart_slot_device::line_value new_cart = active_cts_slot().get_line_value(cococart_slot_device::line::CART);
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if (new_cart != old_cart)
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update_line(active_cts_slot_number(), cococart_slot_device::line::CART);
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}
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//-------------------------------------------------
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// ff7f_write
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//-------------------------------------------------
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WRITE8_MEMBER(coco_multipak_device::ff7f_write)
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{
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set_select(data);
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}
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//-------------------------------------------------
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// update_line
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//-------------------------------------------------
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void coco_multipak_device::update_line(int slot_number, cococart_slot_device::line line)
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{
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bool propagate;
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// one of our child devices set a line; we may need to propagate it upwards
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switch (line)
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{
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case cococart_slot_device::line::CART:
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// only propagate if this is coming from the slot specified
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propagate = slot_number == active_cts_slot_number();
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break;
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case cococart_slot_device::line::NMI:
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case cococart_slot_device::line::HALT:
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// always propagate these
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propagate = true;
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break;
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default:
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// do nothing
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propagate = false;
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break;
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}
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if (propagate)
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owning_slot().set_line_value(line, slot(slot_number).get_line_value(line));
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}
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//-------------------------------------------------
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// set_sound_enable
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//-------------------------------------------------
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void coco_multipak_device::set_sound_enable(bool sound_enable)
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{
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// the SOUND_ENABLE (SNDEN) line is different; it is controlled by the CPU
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for (cococart_slot_device *slot : m_slots)
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slot->set_line_value(cococart_slot_device::line::SOUND_ENABLE, sound_enable ? cococart_slot_device::line_value::ASSERT : cococart_slot_device::line_value::CLEAR);
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}
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//-------------------------------------------------
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// get_cart_base
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//-------------------------------------------------
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uint8_t* coco_multipak_device::get_cart_base()
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{
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return active_cts_slot().get_cart_base();
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}
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//-------------------------------------------------
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// read
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//-------------------------------------------------
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READ8_MEMBER(coco_multipak_device::read)
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{
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return active_scs_slot().read(space, offset);
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}
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//-------------------------------------------------
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// write
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//-------------------------------------------------
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WRITE8_MEMBER(coco_multipak_device::write)
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{
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active_scs_slot().write(space, offset, data);
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}
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//-------------------------------------------------
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// multiX_slotX_[cart|nmi|halt] trampolines
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//-------------------------------------------------
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WRITE_LINE_MEMBER(coco_multipak_device::multi_slot1_cart_w) { update_line(1, cococart_slot_device::line::CART); }
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WRITE_LINE_MEMBER(coco_multipak_device::multi_slot1_nmi_w) { update_line(1, cococart_slot_device::line::NMI); }
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WRITE_LINE_MEMBER(coco_multipak_device::multi_slot1_halt_w) { update_line(1, cococart_slot_device::line::HALT); }
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WRITE_LINE_MEMBER(coco_multipak_device::multi_slot2_cart_w) { update_line(2, cococart_slot_device::line::CART); }
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WRITE_LINE_MEMBER(coco_multipak_device::multi_slot2_nmi_w) { update_line(2, cococart_slot_device::line::NMI); }
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WRITE_LINE_MEMBER(coco_multipak_device::multi_slot2_halt_w) { update_line(2, cococart_slot_device::line::HALT); }
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WRITE_LINE_MEMBER(coco_multipak_device::multi_slot3_cart_w) { update_line(3, cococart_slot_device::line::CART); }
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WRITE_LINE_MEMBER(coco_multipak_device::multi_slot3_nmi_w) { update_line(3, cococart_slot_device::line::NMI); }
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WRITE_LINE_MEMBER(coco_multipak_device::multi_slot3_halt_w) { update_line(3, cococart_slot_device::line::HALT); }
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WRITE_LINE_MEMBER(coco_multipak_device::multi_slot4_cart_w) { update_line(4, cococart_slot_device::line::CART); }
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WRITE_LINE_MEMBER(coco_multipak_device::multi_slot4_nmi_w) { update_line(4, cococart_slot_device::line::NMI); }
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WRITE_LINE_MEMBER(coco_multipak_device::multi_slot4_halt_w) { update_line(4, cococart_slot_device::line::HALT); }
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