diff options
Diffstat (limited to 'src/devices/bus/bbc/internal/morleyaa.cpp')
-rw-r--r-- | src/devices/bus/bbc/internal/morleyaa.cpp | 307 |
1 files changed, 307 insertions, 0 deletions
diff --git a/src/devices/bus/bbc/internal/morleyaa.cpp b/src/devices/bus/bbc/internal/morleyaa.cpp new file mode 100644 index 00000000000..e01336c3b5c --- /dev/null +++ b/src/devices/bus/bbc/internal/morleyaa.cpp @@ -0,0 +1,307 @@ +// license:BSD-3-Clause +// copyright-holders:Nigel Barnes +/********************************************************************** + + Morley Electronics 'AA' Master ROM Expansion Board + +**********************************************************************/ + + +#include "emu.h" +#include "morleyaa.h" + + +//************************************************************************** +// DEVICE DEFINITIONS +//************************************************************************** + +DEFINE_DEVICE_TYPE(BBC_MORLEYAA, bbc_morleyaa_device, "bbc_morleyaa", "Morley Electronics 'AA' Master ROM Expansion Board"); + + +//------------------------------------------------- +// ROM( morleyaa ) +//------------------------------------------------- + +ROM_START(morleyaa) + ROM_REGION(0x4000, "aa_rom", 0) + ROM_LOAD("masterboard_200.rom", 0x0000, 0x4000, CRC(d93738ec) SHA1(c80f47e3f661b1636d21ff542c7a39a586008098)) +ROM_END + +//------------------------------------------------- +// device_add_mconfig - add device configuration +//------------------------------------------------- + +void bbc_morleyaa_device::device_add_mconfig(machine_config &config) +{ + /* TODO: romslot0-3 are unavailable when board is fitted, replaced by sockets on board */; + //config.device_remove(":romslot8"); + + /* 8 x 16K rom sockets */ + BBC_ROMSLOT16(config, m_rom[0], bbc_rom_devices, nullptr); + BBC_ROMSLOT16(config, m_rom[1], bbc_rom_devices, nullptr); + BBC_ROMSLOT16(config, m_rom[2], bbc_rom_devices, nullptr); + BBC_ROMSLOT16(config, m_rom[3], bbc_rom_devices, nullptr); + BBC_ROMSLOT16(config, m_rom[4], bbc_rom_devices, nullptr); + BBC_ROMSLOT16(config, m_rom[5], bbc_rom_devices, nullptr); + BBC_ROMSLOT16(config, m_rom[6], bbc_rom_devices, nullptr); + BBC_ROMSLOT16(config, m_rom[7], bbc_rom_devices, nullptr); + /* 4 x 32K rom sockets */ + BBC_ROMSLOT32(config, m_rom[8], bbc_rom_devices, nullptr); + BBC_ROMSLOT32(config, m_rom[9], bbc_rom_devices, nullptr); + BBC_ROMSLOT32(config, m_rom[10], bbc_rom_devices, nullptr); + BBC_ROMSLOT32(config, m_rom[11], bbc_rom_devices, nullptr); +} + + +//------------------------------------------------- +// rom_region - device-specific ROM region +//------------------------------------------------- + +const tiny_rom_entry *bbc_morleyaa_device::device_rom_region() const +{ + return ROM_NAME(morleyaa); +} + + +//************************************************************************** +// LIVE DEVICE +//************************************************************************** + +//------------------------------------------------- +// bbc_morleyaa_device - constructor +//------------------------------------------------- + +bbc_morleyaa_device::bbc_morleyaa_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock) + : device_t(mconfig, BBC_MORLEYAA, tag, owner, clock) + , device_bbc_internal_interface(mconfig, *this) + , m_aa_rom(*this, "aa_rom") + , m_rom(*this, "romslot%u", 0U) +{ +} + +//------------------------------------------------- +// device_start - device-specific startup +//------------------------------------------------- + +void bbc_morleyaa_device::device_start() +{ + /* move internal roms to board */ + memcpy(m_region_swr->base() + 0x20000, m_aa_rom->base(), 0x4000); + + /* register for save states */ + save_item(NAME(m_romsel)); + save_item(NAME(m_banksel)); +} + + +//************************************************************************** +// IMPLEMENTATION +//************************************************************************** + +uint8_t bbc_morleyaa_device::paged_r(offs_t offset) +{ + uint8_t data = 0xff; + + switch (m_romsel) + { + case 8: + data = m_aa_rom->base()[offset]; + break; + case 4: + if (m_banksel & 0x20) + { + /* motherboard ram selected */ + data = m_mb_rom[m_romsel & 0x0e]->read(offset | (m_romsel & 0x01) << 14); + } + else + { + switch (m_banksel & 0x07) + { + case 2: + data = m_rom[0]->read(offset); + break; + case 4: + data = m_rom[2]->read(offset); + break; + case 0: + data = m_rom[4]->read(offset); + break; + case 6: + data = m_rom[6]->read(offset); + break; + case 7: + data = m_rom[8]->read(offset); + break; + case 3: + data = m_rom[9]->read(offset); + break; + case 5: + data = m_rom[10]->read(offset); + break; + case 1: + data = m_rom[11]->read(offset); + break; + } + } + break; + case 5: + if (m_banksel & 0x20) + { + /* motherboard ram selected */ + data = m_mb_rom[m_romsel & 0x0e]->read(offset | (m_romsel & 0x01) << 14); + } + else + { + switch (m_banksel & 0x07) + { + case 2: + data = m_rom[1]->read(offset); + break; + case 4: + data = m_rom[3]->read(offset); + break; + case 0: + data = m_rom[5]->read(offset); + break; + case 6: + data = m_rom[7]->read(offset); + break; + case 7: + data = m_rom[8]->read(offset | 0x4000); + break; + case 3: + data = m_rom[9]->read(offset | 0x4000); + break; + case 5: + data = m_rom[10]->read(offset | 0x4000); + break; + case 1: + data = m_rom[11]->read(offset | 0x4000); + break; + } + } + break; + case 6: + if (m_banksel & 0x40) + { + /* motherboard ram selected */ + data = m_mb_rom[m_romsel & 0x0e]->read(offset | (m_romsel & 0x01) << 14); + } + else + { + switch (bitswap<8>(m_banksel, 2, 6, 5, 0, 1, 7, 3, 4) & 0x07) + { + case 2: + data = m_rom[0]->read(offset); + break; + case 4: + data = m_rom[2]->read(offset); + break; + case 0: + data = m_rom[4]->read(offset); + break; + case 6: + data = m_rom[6]->read(offset); + break; + case 7: + data = m_rom[8]->read(offset); + break; + case 3: + data = m_rom[9]->read(offset); + break; + case 5: + data = m_rom[10]->read(offset); + break; + case 1: + data = m_rom[11]->read(offset); + break; + } + } + break; + case 7: + if (m_banksel & 0x40) + { + /* motherboard ram selected */ + data = m_mb_rom[m_romsel & 0x0e]->read(offset | (m_romsel & 0x01) << 14); + } + else + { + switch (bitswap<8>(m_banksel, 2, 6, 5, 0, 1, 7, 3, 4) & 0x07) + { + case 2: + data = m_rom[1]->read(offset); + break; + case 4: + data = m_rom[3]->read(offset); + break; + case 0: + data = m_rom[5]->read(offset); + break; + case 6: + data = m_rom[7]->read(offset); + break; + case 7: + data = m_rom[8]->read(offset | 0x4000); + break; + case 3: + data = m_rom[9]->read(offset | 0x4000); + break; + case 5: + data = m_rom[10]->read(offset | 0x4000); + break; + case 1: + data = m_rom[11]->read(offset | 0x4000); + break; + } + } + break; + default: + /* 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; + } + + return data; +} + +void bbc_morleyaa_device::paged_w(offs_t offset, uint8_t data) +{ + switch (m_romsel) + { + case 8: + if (offset == 0x3f00) + { + /* bank latch at &BF00 */ + m_banksel = data; + } + break; + case 4: case 5: + if (m_banksel & 0x20) + { + /* motherboard ram selected */ + m_mb_rom[m_romsel & 0x0e]->write(offset | (m_romsel & 0x01) << 14, data); + } + break; + case 6: case 7: + if (m_banksel & 0x40) + { + /* motherboard ram selected */ + m_mb_rom[m_romsel & 0x0e]->write(offset | (m_romsel & 0x01) << 14, data); + } + break; + default: + /* motherboard rom sockets */ + if (m_mb_rom[m_romsel]) + { + m_mb_rom[m_romsel]->write(offset, data); + } + break; + } +} |