diff options
Diffstat (limited to 'src/devices/bus/bbc/internal/stl2m128.cpp')
-rw-r--r-- | src/devices/bus/bbc/internal/stl2m128.cpp | 248 |
1 files changed, 248 insertions, 0 deletions
diff --git a/src/devices/bus/bbc/internal/stl2m128.cpp b/src/devices/bus/bbc/internal/stl2m128.cpp new file mode 100644 index 00000000000..46b595aedfa --- /dev/null +++ b/src/devices/bus/bbc/internal/stl2m128.cpp @@ -0,0 +1,248 @@ +// license:BSD-3-Clause +// copyright-holders:Nigel Barnes +/********************************************************************** + + Solidisk Twomeg 128K Shadow and Sideways ROM/RAM board + +**********************************************************************/ + + +#include "emu.h" +#include "stl2m128.h" + + +//************************************************************************** +// DEVICE DEFINITIONS +//************************************************************************** + +DEFINE_DEVICE_TYPE(BBC_STL2M128, bbc_stl2m128_device, "bbc_stl2m128", "Solidisk Twomeg 128K RAM/ROM Expansion"); + + +//------------------------------------------------- +// INPUT_PORTS( stl2m128 ) +//------------------------------------------------- + +static INPUT_PORTS_START(stl2m128) + PORT_START("wp") + PORT_CONFNAME(0x01, 0x00, "Write Protect Sideways RAM") + PORT_CONFSETTING(0x00, DEF_STR(No)) + PORT_CONFSETTING(0x01, DEF_STR(Yes)) +INPUT_PORTS_END + +//------------------------------------------------- +// input_ports - device-specific input ports +//------------------------------------------------- + +ioport_constructor bbc_stl2m128_device::device_input_ports() const +{ + return INPUT_PORTS_NAME(stl2m128); +} + +//------------------------------------------------- +// ROM( stl2m128 ) +//------------------------------------------------- + +ROM_START(stl2m128) + ROM_REGION(0x4000, "rom", ROMREGION_ERASEFF) + // ROM image usually distributed on floppy, to load into RAM + ROM_LOAD("manger128-1.00.rom", 0x0000, 0x102a, CRC(dbe84acb) SHA1(d170632b88d0ab276a919b0076dca305094a39b2)) +ROM_END + + +//------------------------------------------------- +// device_add_mconfig - add device configuration +//------------------------------------------------- + +void bbc_stl2m128_device::device_add_mconfig(machine_config &config) +{ + BBC_ROMSLOT16(config, m_rom[4], bbc_rom_devices, "ram").set_fixed_ram(true); + BBC_ROMSLOT16(config, m_rom[5], bbc_rom_devices, "ram").set_fixed_ram(true); + BBC_ROMSLOT16(config, m_rom[6], bbc_rom_devices, "ram").set_fixed_ram(true); + BBC_ROMSLOT16(config, m_rom[7], bbc_rom_devices, "ram").set_fixed_ram(true); + BBC_ROMSLOT16(config, m_rom[8], bbc_rom_devices, nullptr); + BBC_ROMSLOT16(config, m_rom[9], bbc_rom_devices, nullptr); + BBC_ROMSLOT16(config, m_rom[10], bbc_rom_devices, nullptr); + BBC_ROMSLOT16(config, m_rom[11], bbc_rom_devices, nullptr); + BBC_ROMSLOT16(config, m_rom[12], bbc_rom_devices, "ram").set_fixed_ram(true); + BBC_ROMSLOT16(config, m_rom[13], bbc_rom_devices, "ram").set_fixed_ram(true); + BBC_ROMSLOT16(config, m_rom[14], bbc_rom_devices, "ram").set_fixed_ram(true); + BBC_ROMSLOT16(config, m_rom[15], bbc_rom_devices, "ram").set_fixed_ram(true); +} + +//------------------------------------------------- +// rom_region - device-specific ROM region +//------------------------------------------------- + +const tiny_rom_entry *bbc_stl2m128_device::device_rom_region() const +{ + return ROM_NAME(stl2m128); +} + + +//************************************************************************** +// LIVE DEVICE +//************************************************************************** + +//------------------------------------------------- +// bbc_stl2m128_device - constructor +//------------------------------------------------- + +bbc_stl2m128_device::bbc_stl2m128_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock) + : device_t(mconfig, BBC_STL2M128, tag, owner, clock) + , device_bbc_internal_interface(mconfig, *this) + , m_rom(*this, "romslot%u", 0U) + , m_wp(*this, "wp") +{ +} + + +//------------------------------------------------- +// device_start - device-specific startup +//------------------------------------------------- + +void bbc_stl2m128_device::device_start() +{ + m_ram = std::make_unique<uint8_t[]>(0x20000); + + /* copy rom image into ram bank c */ + memcpy(&m_ram[0x10000], memregion("rom")->base(), 0x4000); + + /* move internal roms to board */ + memmove(m_region_swr->base() + 0x20000, m_region_swr->base(), 0x10000); + memset(m_region_swr->base(), 0xff, 0x10000); + + /* register for save states */ + save_pointer(NAME(m_ram), 0x20000); + save_item(NAME(m_romsel)); + save_item(NAME(m_shadow)); +} + + +//************************************************************************** +// IMPLEMENTATION +//************************************************************************** + +void bbc_stl2m128_device::romsel_w(offs_t offset, uint8_t data) +{ + switch (offset & 0x0c) + { + case 0x00: + m_romsel = data & 0x0f; + break; + case 0x04: + m_shadow = data; + break; + } +} + +uint8_t bbc_stl2m128_device::ram_r(offs_t offset) +{ + uint8_t data = 0xff; + + if (BIT(m_shadow, 7) && offset >= 0x2000) + { + if (BIT(m_shadow, 1)) + { + /* banks E/F */ + data = m_ram[offset | 0x18000]; + } + else + { + /* banks C/D */ + data = m_ram[offset | 0x10000]; + } + } + else + { + data = m_mb_ram->pointer()[offset]; + } + + return data; +} + +void bbc_stl2m128_device::ram_w(offs_t offset, uint8_t data) +{ + if (BIT(m_shadow, 7) && offset >= 0x2000) + { + if (BIT(m_shadow, 1)) + { + /* banks E/F */ + m_ram[offset | 0x18000] = data; + } + else + { + /* banks C/D */ + m_ram[offset | 0x10000] = data; + } + } + else + { + m_mb_ram->pointer()[offset] = data; + } +} + +uint8_t bbc_stl2m128_device::paged_r(offs_t offset) +{ + uint8_t data = 0xff; + + switch (m_romsel) + { + case 0: case 1: case 2: case 3: + /* motherboard rom sockets */ + if (m_mb_rom[m_romsel] && m_mb_rom[m_romsel]->present()) + { + data = m_mb_rom[m_romsel]->read(offset); + } + else + { + data = m_region_swr->base()[offset + (m_romsel << 14)]; + } + break; + case 8: case 9: case 10: case 11: + /* expansion board rom sockets */ + if (m_rom[m_romsel] && m_rom[m_romsel]->present()) + { + data = m_rom[m_romsel]->read(offset); + } + else + { + data = m_region_swr->base()[offset + (m_romsel << 14)]; + } + break; + case 4: case 5: case 6: case 7: case 12: case 13: case 14: case 15: + /* expansion board ram sockets */ + data = m_ram[offset | ((m_romsel & 0x03) << 14) | ((m_romsel & 0x08) << 13)]; + break; + } + + + return data; +} + +void bbc_stl2m128_device::paged_w(offs_t offset, uint8_t data) +{ + switch (m_romsel) + { + case 0: case 1: case 2: case 3: + /* motherboard rom sockets */ + if (m_mb_rom[m_romsel]) + { + m_mb_rom[m_romsel]->write(offset, data); + } + break; + case 8: case 9: case 10: case 11: + /* expansion board rom sockets */ + if (m_rom[m_romsel]) + { + m_rom[m_romsel]->write(offset, data); + } + break; + case 4: case 5: case 6: case 7: case 12: case 13: case 14: case 15: + /* expansion board ram sockets */ + if (!m_wp->read()) + { + m_ram[offset | ((m_romsel & 0x03) << 14) | ((m_romsel & 0x08) << 13)] = data; + } + break; + } +} |