diff options
Diffstat (limited to 'src/devices/bus/wangpc/emb.c')
-rw-r--r-- | src/devices/bus/wangpc/emb.c | 175 |
1 files changed, 175 insertions, 0 deletions
diff --git a/src/devices/bus/wangpc/emb.c b/src/devices/bus/wangpc/emb.c new file mode 100644 index 00000000000..e53b8ea2308 --- /dev/null +++ b/src/devices/bus/wangpc/emb.c @@ -0,0 +1,175 @@ +// license:BSD-3-Clause +// copyright-holders:Curt Coder +/********************************************************************** + + Wang PC-PM031-B Extended Memory Board emulation + +**********************************************************************/ + +#include "emb.h" + + + +//************************************************************************** +// MACROS/CONSTANTS +//************************************************************************** + +#define LOG 0 + +#define OPTION_ID 0x3f + +#define RAM_SIZE 0x40000 + +#define A19_A18_A17 ((offset >> 16) & 0x07) +#define BASE(bank) ((m_option >> (bank * 4)) & 0x07) +#define ENABLE(bank) BIT(m_option, (bank * 4) + 3) +#define RAM_BANK(bank) m_ram[(bank * 0x10000) | (offset & 0xffff)] + + + +//************************************************************************** +// DEVICE DEFINITIONS +//************************************************************************** + +const device_type WANGPC_EMB = &device_creator<wangpc_emb_device>; + + + +//************************************************************************** +// LIVE DEVICE +//************************************************************************** + +//------------------------------------------------- +// wangpc_emb_device - constructor +//------------------------------------------------- + +wangpc_emb_device::wangpc_emb_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock) : + device_t(mconfig, WANGPC_EMB, "Wang PC-PM031-B", tag, owner, clock, "wangpc_emb", __FILE__), + device_wangpcbus_card_interface(mconfig, *this), + m_ram(*this, "ram") +{ +} + + +//------------------------------------------------- +// device_start - device-specific startup +//------------------------------------------------- + +void wangpc_emb_device::device_start() +{ + // allocate memory + m_ram.allocate(RAM_SIZE); + + // state saving + save_item(NAME(m_option)); + save_item(NAME(m_parity_error)); + save_item(NAME(m_parity_odd)); +} + + +//------------------------------------------------- +// device_reset - device-specific reset +//------------------------------------------------- + +void wangpc_emb_device::device_reset() +{ + m_option = 0; + m_parity_error = 0; + m_parity_odd = 1; +} + + +//------------------------------------------------- +// wangpcbus_mrdc_r - memory read +//------------------------------------------------- + +UINT16 wangpc_emb_device::wangpcbus_mrdc_r(address_space &space, offs_t offset, UINT16 mem_mask) +{ + UINT16 data = 0xffff; + + for (int bank = 0; bank < 4; bank++) + { + if (ENABLE(bank) && (A19_A18_A17 == BASE(bank))) + { + data &= RAM_BANK(bank); + } + } + + return data; +} + + +//------------------------------------------------- +// wangpcbus_amwc_w - memory write +//------------------------------------------------- + +void wangpc_emb_device::wangpcbus_amwc_w(address_space &space, offs_t offset, UINT16 mem_mask, UINT16 data) +{ + for (int bank = 0; bank < 4; bank++) + { + if (ENABLE(bank) && (A19_A18_A17 == BASE(bank))) + { + RAM_BANK(bank) = data; + } + } +} + + +//------------------------------------------------- +// wangpcbus_iorc_r - I/O read +//------------------------------------------------- + +UINT16 wangpc_emb_device::wangpcbus_iorc_r(address_space &space, offs_t offset, UINT16 mem_mask) +{ + UINT16 data = 0xffff; + + if (sad(offset)) + { + switch (offset & 0x7f) + { + case 0xc0/2: + data = m_option; + break; + + case 0xfe/2: + data = 0xfc00 | (m_parity_odd << 9) | (m_parity_error << 8) | OPTION_ID; + break; + } + + logerror("emb read %06x:%02x\n", offset*2, data); + } + + return data; +} + + +//------------------------------------------------- +// wangpcbus_aiowc_w - I/O write +//------------------------------------------------- + +void wangpc_emb_device::wangpcbus_aiowc_w(address_space &space, offs_t offset, UINT16 mem_mask, UINT16 data) +{ + if (sad(offset)) + { + logerror("emb write %06x:%02x\n", offset*2, data); + + switch (offset & 0x7f) + { + case 0xc0/2: + m_option = data; + break; + + case 0xce/2: + m_parity_error = 0; + break; + + case 0xfc/2: + device_reset(); + break; + + case 0xfe/2: + m_parity_odd = BIT(data, 9); + break; + } + } +} |