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// license:BSD-3-Clause
// copyright-holders:Olivier Galibert
/***************************************************************************
m6502mtu.cpp
M6502 with MTU external banking hardware
***************************************************************************/
#include "emu.h"
#include "m6502mtu.h"
DEFINE_DEVICE_TYPE(M6502MTU, m6502mtu_device, "m6502mtu", "M6502 with MTU banking")
m6502mtu_device::m6502mtu_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock) :
m6502_device(mconfig, M6502MTU, tag, owner, clock)
{
program_config.m_addr_width = 18;
sprogram_config.m_addr_width = 18;
}
void m6502mtu_device::device_start()
{
mintf = nullptr;
space(AS_PROGRAM).specific(cprogram);
space(has_space(AS_OPCODES) ? AS_OPCODES : AS_PROGRAM).specific(csprogram);
save_item(NAME(low_instruction));
save_item(NAME(interrupt_mode));
save_item(NAME(pbank));
save_item(NAME(dbank));
init();
}
void m6502mtu_device::device_reset()
{
m6502_device::device_reset();
pbank = 0;
dbank = 0;
low_instruction = false;
interrupt_mode = false;
}
void m6502mtu_device::prefetchd()
{
sync = true;
sync_w(ASSERT_LINE);
NPC = PC;
low_instruction = PC < 0x200;
IR = csprogram.read_byte(low_instruction || interrupt_mode ? PC : PC | pbank);
sync = false;
sync_w(CLEAR_LINE);
if((nmi_pending || ((irq_state || apu_irq_state) && !(P & F_I))) && !inhibit_interrupts) {
irq_taken = true;
IR = 0x00;
} else
PC++;
}
void m6502mtu_device::prefetchd_noirq()
{
sync = true;
sync_w(ASSERT_LINE);
NPC = PC;
low_instruction = PC < 0x200;
IR = csprogram.read_byte(low_instruction || interrupt_mode ? PC : PC | pbank);
sync = false;
sync_w(CLEAR_LINE);
PC++;
}
#include "cpu/m6502/m6502mtu.hxx"
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