bus.cpp

// (C) 2018-2024 by Folkert van Heusden
// Released under MIT license

#include "gen.h"
#include <ArduinoJson.h>
#include <assert.h>
#include <stdio.h>
#include <string.h>

#include "bus.h"
#include "cpu.h"
#include "dc11.h"
#include "kw11-l.h"
#include "log.h"
#include "memory.h"
#include "mmu.h"
#include "tm-11.h"
#include "tty.h"
#include "utils.h"

#if defined(ESP32)
#include <esp_debug_helpers.h>
#endif


bus::bus()
{
	mmu_ = new mmu();

	kw11_l_ = new kw11_l(this);

	reset();
}

bus::~bus()
{
	delete kw11_l_;
	delete c;
	delete tm11;
	delete rk05_;
	delete rl02_;
	delete tty_;
	delete mmu_;
	delete m;
	delete dc11_;
	delete rp06_;
}

JsonDocument bus::serialize() const
{
	JsonDocument j_out;

	if (m)
		j_out["memory"] = m->serialize();

	if (kw11_l_)
		j_out["kw11-l"] = kw11_l_->serialize();

	if (tty_)
		j_out["tty"]    = tty_->serialize();

	if (mmu_)
		j_out["mmu"]    = mmu_->serialize();

	if (c)
		j_out["cpu"]    = c->serialize();

	if (rl02_)
		j_out["rl02"]   = rl02_->serialize();

	if (rk05_)
		j_out["rk05"]   = rk05_->serialize();

	if (dc11_)
		j_out["dc11"]   = dc11_->serialize();

	if (rp06_)
		j_out["rp06"]   = rp06_->serialize();

	// TODO: tm11

	return j_out;
}

bus *bus::deserialize(const JsonDocument j, console *const cnsl, std::atomic_uint32_t *const event)
{
	bus *b = new bus();

	memory *m = nullptr;
	if (j.containsKey("memory")) {
		m = memory::deserialize(j["memory"]);
		b->add_ram(m);
	}

	if (j.containsKey("tty"))
		b->add_tty(tty::deserialize(j["tty"], b, cnsl));

	cpu *c = nullptr;
	if (j.containsKey("cpu")) {
		c = cpu::deserialize(j["cpu"], b, event);
		b->add_cpu(c);
	}

	if (j.containsKey("mmu"))
		b->add_mmu(mmu::deserialize(j["mmu"], m, c));

	if (j.containsKey("rl02"))
		b->add_rl02(rl02::deserialize(j["rl02"], b));

	if (j.containsKey("rk05"))
		b->add_rk05(rk05::deserialize(j["rk05"], b));

	if (j.containsKey("kw11-l"))
		b->add_KW11_L(kw11_l::deserialize(j["kw11-l"], b, cnsl));

	if (j.containsKey("dc11"))
		b->add_DC11(dc11::deserialize(j["dc11"], b));

	if (j.containsKey("rp06"))
		b->add_RP06(rp06::deserialize(j["rp06"], b));

	// TODO: tm11

	return b;
}

void bus::show_state(console *const cnsl) const
{
	cnsl->put_string_lf(format("Microprogram break register: %06o", microprogram_break_register));
	cnsl->put_string_lf(format("Console switches: %06o", console_switches));
	cnsl->put_string_lf(format("Console LEDs: %06o", console_leds));
}

void bus::set_memory_size(const int n_pages)
{
	uint32_t n_bytes = n_pages * 8192l;

	delete m;
	m = new memory(n_bytes);

	mmu_->begin(m, c);

	TRACE("Memory is now %u kB in size", n_bytes / 1024);
}

void bus::reset()
{
	if (m)
		m->reset();
	if (mmu_)
		mmu_->reset();
	if (c)
		c->reset();
	if (tm11)
		tm11->reset();
	if (rk05_)
		rk05_->reset();
	if (rl02_)
		rl02_->reset();
	if (tty_)
		tty_->reset();
	if (kw11_l_)
		kw11_l_->reset();
	if (dc11_)
		dc11_->reset();
	if (rp06_)
		rp06_->reset();
}

void bus::add_RP06(rp06 *const rp06_)
{
	delete this->rp06_;
	this->rp06_ = rp06_;
}

void bus::add_KW11_L(kw11_l *const kw11_l_)
{
	delete this->kw11_l_;
	this->kw11_l_ = kw11_l_;
}

void bus::add_ram(memory *const m)
{
	delete this->m;
	this->m = m;

	mmu_->begin(m, c);
}

void bus::add_mmu(mmu *const mmu_)
{
	delete this->mmu_;
	this->mmu_ = mmu_;

	mmu_->begin(m, c);
}

void bus::add_cpu(cpu *const c)
{
	delete this->c;
	this->c = c;

	if (mmu_)
		mmu_->begin(m, c);
}

void bus::add_tm11(tm_11 *const tm11)
{
	delete this->tm11;
	this->tm11= tm11;
} 

void bus::add_rk05(rk05 *const rk05_)
{
	delete this->rk05_;
	this->rk05_ = rk05_;
} 

void bus::add_rl02(rl02 *const rl02_)
{
	delete this->rl02_;
	this->rl02_ = rl02_;
}

void bus::add_tty(tty *const tty_)
{
	delete this->tty_;
	this->tty_ = tty_;
}

void bus::add_DC11(dc11 *const dc11_)
{
	delete this->dc11_;
	this->dc11_ = dc11_;
}

void bus::del_DC11()
{
	delete dc11_;
	dc11_ = nullptr;
}

void bus::init()
{
	mmu_->setMMR0(0);
	mmu_->setMMR3(0);
}

uint16_t bus::read(const uint16_t addr_in, const word_mode_t word_mode, const rm_selection_t mode_selection, const d_i_space_t space)
{
	int  run_mode     = mode_selection == rm_cur ? c->getPSW_runmode() : c->getPSW_prev_runmode();

	uint32_t m_offset = mmu_->calculate_physical_address(run_mode, addr_in, false, space);

	uint32_t io_base  = mmu_->get_io_base();
	bool     is_io    = m_offset >= io_base;

	if (is_io) {
		uint16_t a = m_offset - io_base + 0160000;  // TODO

		//// REGISTERS ////
		if (a >= ADDR_KERNEL_R && a <= ADDR_KERNEL_R + 5) { // kernel R0-R5
			uint16_t temp = c->get_register(a - ADDR_KERNEL_R) & (word_mode == wm_byte ? 0xff : 0xffff);
			TRACE("READ-I/O kernel R%d: %06o", a - ADDR_KERNEL_R, temp);
			return temp;
		}
		if (a >= ADDR_USER_R && a <= ADDR_USER_R + 5) { // user R0-R5
			uint16_t temp = c->get_register(a - ADDR_USER_R) & (word_mode == wm_byte ? 0xff : 0xffff);
			TRACE("READ-I/O user R%d: %06o", a - ADDR_USER_R, temp);
			return temp;
		}
		if (a == ADDR_KERNEL_SP) { // kernel SP
			uint16_t temp = c->getStackPointer(0) & (word_mode == wm_byte ? 0xff : 0xffff);
			TRACE("READ-I/O kernel SP: %06o", temp);
			return temp;
		}
		if (a == ADDR_PC) { // PC
			uint16_t temp = c->getPC() & (word_mode == wm_byte ? 0xff : 0xffff);
			TRACE("READ-I/O PC: %06o", temp);
			return temp;
		}
		if (a == ADDR_SV_SP) { // supervisor SP
			uint16_t temp = c->getStackPointer(1) & (word_mode == wm_byte ? 0xff : 0xffff);
			TRACE("READ-I/O supervisor SP: %06o", temp);
			return temp;
		}
		if (a == ADDR_USER_SP) { // user SP
			uint16_t temp = c->getStackPointer(3) & (word_mode == wm_byte ? 0xff : 0xffff);
			TRACE("READ-I/O user SP: %06o", temp);
			return temp;
		}
		///^ registers ^///

		if ((a & 1) && word_mode == wm_word) [[unlikely]] {
			TRACE("READ-I/O odd address %06o UNHANDLED", a);
			mmu_->trap_if_odd(addr_in, run_mode, space, false);
			throw 0;
			return 0;
		}

		if (a == ADDR_CPU_ERR) { // cpu error register
			uint16_t temp = mmu_->getCPUERR() & 0xff;
			TRACE("READ-I/O CPU error: %03o", temp);
			return temp;
		}

		if (a == ADDR_MAINT) { // MAINT
			uint16_t temp = 1; // POWER OK
			TRACE("READ-I/O MAINT: %o", temp);
			return temp;
		}

		if (a == ADDR_CONSW) { // console switch & display register
			uint16_t temp = console_switches;
			TRACE("READ-I/O console switch: %o", temp);
			return temp;
		}

		if (a == ADDR_PIR || a == ADDR_PIR + 1) { // PIR
			uint16_t temp = 0;

			uint16_t PIR  = mmu_->getPIR();

			if (word_mode == wm_word)
				temp = PIR;
			else
				temp = a == ADDR_PIR ? PIR & 255 : PIR >> 8;

			TRACE("READ-I/O PIR: %o", temp);
			return temp;
		}

		if (a == ADDR_SYSTEM_ID) {
			uint16_t temp = 011064;
			TRACE("READ-I/O system id: %o", temp);
			return temp;
		}

		if (a == ADDR_LFC) // line frequency clock and status register
			return kw11_l_->read_word(a);

		if (a == ADDR_LP11CSR) { // printer, CSR register, LP11
			uint16_t temp = 0x80;
			TRACE("READ-I/O LP11 CSR: %o", temp);
			return temp;
		}

		/// MMU ///
		if ((a >= ADDR_PDR_SV_START && a < ADDR_PAR_SV_END) ||
				(a >= ADDR_PDR_K_START && a < ADDR_PAR_K_END) ||
				(a >= ADDR_PDR_U_START && a < ADDR_PAR_U_END)) {
			if (word_mode == wm_word)
				return mmu_->read_word(a);

			return mmu_->read_byte(a);
		}
		///////////

		if (a >= 0177740 && a <= 0177753) { // cache control register and others
			TRACE("READ-I/O cache control register/others (%06o): %o", a, 0);
			// TODO
			return 0;
		}

		if (a >= 0170200 && a <= 0170377) { // unibus map
			TRACE("READ-I/O unibus map (%06o): %o", a, 0);
			// TODO
			return 0;
		}

		if (a >= 0172100 && a <= 0172137) {  // MM11-LP parity
			TRACE("READ-I/O MM11-LP parity (%06o): %o", a, 1);
			return 1;
		}

		if (word_mode == wm_byte) {
			if (a == ADDR_PSW) { // PSW
				uint8_t temp = c->getPSW();
				TRACE("READ-I/O PSW LSB: %03o", temp);
				return temp;
			}

			if (a == ADDR_PSW + 1) {
				uint8_t temp = c->getPSW() >> 8;
				TRACE("READ-I/O PSW MSB: %03o", temp);
				return temp;
			}
			if (a == ADDR_STACKLIM) { // stack limit register
				uint8_t temp = c->getStackLimitRegister();
				TRACE("READ-I/O stack limit register (low): %03o", temp);
				return temp;
			}
			if (a == ADDR_STACKLIM + 1) { // stack limit register
				uint8_t temp = c->getStackLimitRegister() >> 8;
				TRACE("READ-I/O stack limit register (high): %03o", temp);
				return temp;
			}

			if (a == ADDR_MICROPROG_BREAK_REG) {  // microprogram break register
				uint8_t temp = microprogram_break_register;
				TRACE("READ-I/O microprogram break register (low): %03o", temp);
				return temp;
			}
			if (a == ADDR_MICROPROG_BREAK_REG + 1) {  // microprogram break register
				uint8_t temp = microprogram_break_register >> 8;
				TRACE("READ-I/O microprogram break register (high): %03o", temp);
				return temp;
			}

			if (a == ADDR_MMR0) {
				uint8_t temp = mmu_->getMMR0();
				TRACE("READ-I/O MMR0 LO: %03o", temp);
				return temp;
			}
			if (a == ADDR_MMR0 + 1) {
				uint8_t temp = mmu_->getMMR0() >> 8;
				TRACE("READ-I/O MMR0 HI: %03o", temp);
				return temp;
			}
		}
		else {
			if (a == ADDR_MMR0) {
				uint16_t temp = mmu_->getMMR0();
				TRACE("READ-I/O MMR0: %06o", temp);
				return temp;
			}

			if (a == ADDR_MMR1) { // MMR1
				uint16_t temp = mmu_->getMMR1();
				TRACE("READ-I/O MMR1: %06o", temp);
				return temp;
			}

			if (a == ADDR_MMR2) { // MMR2
				uint16_t temp = mmu_->getMMR2();
				TRACE("READ-I/O MMR2: %06o", temp);
				return temp;
			}

			if (a == ADDR_MMR3) { // MMR3
				uint16_t temp = mmu_->getMMR3();
				TRACE("READ-I/O MMR3: %06o", temp);
				return temp;
			}

			if (a == ADDR_PSW) { // PSW
				uint16_t temp = c->getPSW();
				TRACE("READ-I/O PSW: %06o", temp);
				return temp;
			}

			if (a == ADDR_STACKLIM) { // stack limit register
				uint16_t temp = c->getStackLimitRegister();
				TRACE("READ-I/O stack limit register: %06o", temp);
				return temp;
			}

			if (a == ADDR_CPU_ERR) { // cpu error register
				uint16_t temp = mmu_->getCPUERR();
				TRACE("READ-I/O CPUERR: %06o", temp);
				return temp;
			}

			if (a == ADDR_MICROPROG_BREAK_REG) {  // microprogram break register
				uint16_t temp = microprogram_break_register;
				TRACE("READ-I/O microprogram break register: %06o", temp);
				return temp;
			}
		}

		if (tm11 && a >= TM_11_BASE && a < TM_11_END)
			return word_mode == wm_byte ? tm11->read_byte(a) : tm11->read_word(a);

		if (rk05_ && a >= RK05_BASE && a < RK05_END)
			return word_mode == wm_byte ? rk05_->read_byte(a) : rk05_->read_word(a);

		if (rl02_ && a >= RL02_BASE && a < RL02_END)
			return word_mode == wm_byte ? rl02_->read_byte(a) : rl02_->read_word(a);

		if (tty_ && a >= PDP11TTY_BASE && a < PDP11TTY_END)
			return word_mode == wm_byte ? tty_->read_byte(a) : tty_->read_word(a);

		if (dc11_ && a >= DC11_BASE && a < DC11_END)
			return word_mode == wm_byte ? dc11_->read_byte(a) : dc11_->read_word(a);

		if (rp06_ && a >= RP06_BASE && a < RP06_END)
			return word_mode == wm_byte ? rp06_->read_byte(a) : rp06_->read_word(a);

		// LO size register field must be all 1s, so subtract 1
		uint32_t system_size = m->get_memory_size() / 64 - 1;

		if (a == ADDR_SYSSIZE + 2) {  // system size HI
			uint16_t temp = system_size >> 16;
			TRACE("READ-I/O accessing system size HI: %06o", temp);
			return temp;
		}

		if (a == ADDR_SYSSIZE) {  // system size LO
			uint16_t temp = system_size;
			TRACE("READ-I/O accessing system size LO: %06o", temp);
			return temp;
		}

		TRACE("READ-I/O UNHANDLED read %08o (%c), (base: %o)", m_offset, word_mode == wm_byte ? 'B' : ' ', mmu_->get_io_base());

		c->trap(004);  // no such i/o
		throw 1;

		return -1;
	}

	if ((addr_in & 1) && word_mode == wm_word) {
		TRACE("READ from %06o - odd address!", addr_in);
		mmu_->trap_if_odd(addr_in, run_mode, space, false);
		throw 2;
		return 0;
	}

	if (m_offset >= m->get_memory_size()) {
		c->trap(004);  // no such RAM
		throw 1;
	}

	uint16_t temp = 0;
	if (word_mode == wm_byte)
		temp = m->read_byte(m_offset);
	else
		temp = m->read_word(m_offset);

	TRACE("READ from %06o/%07o %c %c: %06o (%s)", addr_in, m_offset, space == d_space ? 'D' : 'I', word_mode == wm_byte ? 'B' : 'W', temp, mode_selection == rm_prev ? "prev" : "cur");

	return temp;
}

bool bus::is_psw(const uint16_t addr, const int run_mode, const d_i_space_t space) const
{
	auto meta = mmu_->calculate_physical_address(run_mode, addr);

	if (space == d_space && meta.physical_data_is_psw)
		return true;

	if (space == i_space && meta.physical_instruction_is_psw)
		return true;

	return false;
}

bool bus::write(const uint16_t addr_in, const word_mode_t word_mode, uint16_t value, const rm_selection_t mode_selection, const d_i_space_t space)
{
	int           run_mode = mode_selection == rm_cur ? c->getPSW_runmode() : c->getPSW_prev_runmode();

	const uint8_t apf      = addr_in >> 13; // active page field

	bool          is_data  = space == d_space;
	bool          d        = is_data && mmu_->get_use_data_space(run_mode);

	if (mmu_->is_enabled() && (addr_in & 1) == 0 /* TODO remove this? */ && addr_in != ADDR_MMR0)
		mmu_->set_page_written_to(run_mode, d, apf);

	uint32_t m_offset = mmu_->calculate_physical_address(run_mode, addr_in, true, space);

	uint32_t io_base  = mmu_->get_io_base();
	bool     is_io    = m_offset >= io_base;

	if (is_io) {
		uint16_t a = m_offset - io_base + 0160000;  // TODO

		if (word_mode == wm_byte) {
			if (a == ADDR_PSW || a == ADDR_PSW + 1) { // PSW
				TRACE("WRITE-I/O PSW %s: %03o", a & 1 ? "MSB" : "LSB", value);

				uint16_t vtemp = c->getPSW();

				update_word(&vtemp, a & 1, value);

				vtemp &= ~16;  // cannot set T bit via this

				c->setPSW(vtemp, false);

				return true;
			}

			if (a == ADDR_STACKLIM || a == ADDR_STACKLIM + 1) { // stack limit register
				TRACE("WRITE-I/O stack limit register %s: %03o", a & 1 ? "MSB" : "LSB", value);

				uint16_t v = c->getStackLimitRegister();

				update_word(&v, a & 1, value);

				v |= 0377;

				c->setStackLimitRegister(v);

				return false;
			}

			if (a == ADDR_MICROPROG_BREAK_REG || a == ADDR_MICROPROG_BREAK_REG + 1) {  // microprogram break register
				TRACE("WRITE-I/O micropram break register %s: %03o", a & 1 ? "MSB" : "LSB", value);

				update_word(&microprogram_break_register, a & 1, value);

				return false;
			}

			if (a == ADDR_MMR0 || a == ADDR_MMR0 + 1) { // MMR0
				TRACE("WRITE-I/O MMR0 register %s: %03o", a & 1 ? "MSB" : "LSB", value);

				uint16_t temp = mmu_->getMMR0();
				update_word(&temp, a & 1, value);
				mmu_->setMMR0(temp);

				return false;
			}
		}
		else {
			if (a == ADDR_PSW) { // PSW
				TRACE("WRITE-I/O PSW: %06o", value);
				c->setPSW(value & ~16, false);
				return { true };
			}

			if (a == ADDR_STACKLIM) { // stack limit register
				TRACE("WRITE-I/O stack limit register: %06o", value);
				c->setStackLimitRegister(value & 0xff00);
				return false;
			}

			if (a >= ADDR_KERNEL_R && a <= ADDR_KERNEL_R + 5) { // kernel R0-R5
				int reg = a - ADDR_KERNEL_R;
				TRACE("WRITE-I/O kernel R%d: %06o", reg, value);
				c->set_register(reg, value);
				return false;
			}
			if (a >= ADDR_USER_R && a <= ADDR_USER_R + 5) { // user R0-R5
				int reg = a - ADDR_USER_R;
				TRACE("WRITE-I/O user R%d: %06o", reg, value);
				c->set_register(reg, value);
				return false;
			}
			if (a == ADDR_KERNEL_SP) { // kernel SP
				TRACE("WRITE-I/O kernel SP: %06o", value);
				c->setStackPointer(0, value);
				return false;
			}
			if (a == ADDR_PC) { // PC
				TRACE("WRITE-I/O PC: %06o", value);
				c->setPC(value);
				return false;
			}
			if (a == ADDR_SV_SP) { // supervisor SP
				TRACE("WRITE-I/O supervisor sp: %06o", value);
				c->setStackPointer(1, value);
				return false;
			}
			if (a == ADDR_USER_SP) { // user SP
				TRACE("WRITE-I/O user sp: %06o", value);
				c->setStackPointer(3, value);
				return false;
			}

			if (a == ADDR_MICROPROG_BREAK_REG) {  // microprogram break register
				TRACE("WRITE-I/O microprogram break register: %06o", value);
				microprogram_break_register = value & 0xff; // only 8b on 11/70?
				return false;
			}
		}

		if (a == ADDR_CPU_ERR) { // cpu error register
			TRACE("WRITE-I/O CPUERR: %06o", value);
			mmu_->setCPUERR(0);
			return false;
		}

		if (a == ADDR_MMR3) { // MMR3
			TRACE("WRITE-I/O set MMR3: %06o", value);
			mmu_->setMMR3(value);
			return false;
		}

		if (a == ADDR_MMR0) { // MMR0
			TRACE("WRITE-I/O set MMR0: %06o", value);
			mmu_->setMMR0(value);
			return false;
		}

		if (a == ADDR_PIR) { // PIR
			TRACE("WRITE-I/O set PIR: %06o", value);

			value &= 0177000;

			int bits = value >> 9;

			while(bits) {
				value += 042;  // bit 1...3 and 5...7
				bits >>= 1;
			}

			mmu_->setPIR(value);

			return false;
		}

		if (a == ADDR_LFC) { // line frequency clock and status register
			kw11_l_->write_word(a, value);

			return false;
		}

		if (tm11 && a >= TM_11_BASE && a < TM_11_END) {
			TRACE("WRITE-I/O TM11 register %d: %06o", (a - TM_11_BASE) / 2, value);
			word_mode == wm_byte ? tm11->write_byte(a, value) : tm11->write_word(a, value);
			return false;
		}

		if (rk05_ && a >= RK05_BASE && a < RK05_END) {
			TRACE("WRITE-I/O RK05 register %d: %06o", (a - RK05_BASE) / 2, value);
			word_mode == wm_byte ? rk05_->write_byte(a, value) : rk05_->write_word(a, value);
			return false;
		}

		if (rl02_ && a >= RL02_BASE && a < RL02_END) {
			TRACE("WRITE-I/O RL02 register %d: %06o", (a - RL02_BASE) / 2, value);
			word_mode == wm_byte ? rl02_->write_byte(a, value) : rl02_->write_word(a, value);
			return false;
		}

		if (tty_ && a >= PDP11TTY_BASE && a < PDP11TTY_END) {
			TRACE("WRITE-I/O TTY register %d: %06o", (a - PDP11TTY_BASE) / 2, value);
			word_mode == wm_byte ? tty_->write_byte(a, value) : tty_->write_word(a, value);
			return false;
		}

		if (dc11_ && a >= DC11_BASE && a < DC11_END) {
			word_mode == wm_byte ? dc11_->write_byte(a, value) : dc11_->write_word(a, value);
			return false;
		}

		if (rp06_ && a >= RP06_BASE && a < RP06_END) {
			word_mode == wm_byte ? rp06_->write_byte(a, value) : rp06_->write_word(a, value);
			return false;
		}

		if (a >= 0172100 && a <= 0172137) {  // MM11-LP parity
			TRACE("WRITE-I/O MM11-LP parity (%06o): %o", a, value);
			return false;
		}

		/// MMU ///
		if ((a >= ADDR_PDR_SV_START && a < ADDR_PAR_SV_END) ||
				(a >= ADDR_PDR_K_START && a < ADDR_PAR_K_END) ||
				(a >= ADDR_PDR_U_START && a < ADDR_PAR_U_END)) {
			if (word_mode == wm_word)
				mmu_->write_word(a, value);
			else
				mmu_->write_byte(a, value);

			return false;
		}
		///////////

		if (a >= 0177740 && a <= 0177753) { // cache control register and others
			// TODO
			return false;
		}

		if (a >= 0170200 && a <= 0170377) { // unibus map
			TRACE("writing %06o to unibus map (%06o)", value, a);
			// TODO
			return false;
		}

		if (a == ADDR_CONSW) {  // switch register
			console_leds = value;
			return false;
		}

		if (a == ADDR_SYSSIZE || a == ADDR_SYSSIZE + 2)  // system size (is read-only)
			return false;

		if (a == ADDR_SYSTEM_ID)  // is r/o
			return false;

		///////////

		TRACE("WRITE-I/O UNHANDLED %08o(%c): %06o (base: %o)", m_offset, word_mode == wm_byte ? 'B' : 'W', value, mmu_->get_io_base());

		if (word_mode == wm_word && (a & 1)) [[unlikely]] {
			TRACE("WRITE-I/O to %08o (value: %06o) - odd address!", m_offset, value);

			mmu_->trap_if_odd(a, run_mode, space, true);

			throw 8;
		}

		c->trap(004);  // no such i/o

		throw 9;
	}

	if ( (addr_in & 1) && word_mode == wm_word) [[unlikely]] {
		TRACE("WRITE to %06o (value: %06o) - odd address!", addr_in, value);

		mmu_->trap_if_odd(addr_in, run_mode, space, true);

		throw 10;
	}

	TRACE("WRITE to %06o/%07o %c %c: %06o", addr_in, m_offset, space == d_space ? 'D' : 'I', word_mode == wm_byte ? 'B' : 'W', value);

	if (m_offset >= m->get_memory_size()) {
		c->trap(004);  // no such RAM
		throw 1;
	}

	if (word_mode == wm_byte)
		m->write_byte(m_offset, value);
	else
		m->write_word(m_offset, value);

	return false;
}

void bus::write_physical(const uint32_t a, const uint16_t value)
{
	TRACE("physicalWRITE %06o to %o", value, a);

	if (a >= m->get_memory_size()) {
		TRACE("physicalWRITE to %o: trap 004", a);
		c->trap(004);
		throw 12;
	}
	else {
		m->write_word(a, value);
	}
}

uint16_t bus::read_physical(const uint32_t a)
{
	if (a >= m->get_memory_size()) {
		TRACE("physicalREAD from %o: trap 004", a);
		c->trap(004);
		throw 13;
	}

	uint16_t value = m->read_word(a);

	TRACE("physicalREAD %06o from %o", value, a);

	return value;
}

uint16_t bus::read_word(const uint16_t a, const d_i_space_t s)
{
	return read(a, wm_word, rm_cur, s);
}

std::optional<uint16_t> bus::peek_word(const int run_mode, const uint16_t a)
{
	auto meta = mmu_->calculate_physical_address(run_mode, a);

	uint32_t io_base  = mmu_->get_io_base();
	if (meta.physical_instruction >= io_base)
		return { };

	return m->read_word(meta.physical_instruction);
}

void bus::write_word(const uint16_t a, const uint16_t value, const d_i_space_t s)
{
	write(a, wm_word, value, rm_cur, s);
}

uint8_t bus::read_unibus_byte(const uint32_t a)
{
	uint8_t v = 0;
	if (a < m->get_memory_size())
		v = m->read_byte(a);
	TRACE("read_unibus_byte[%08o]=%03o", a, v);
	return v;
}

void bus::write_unibus_byte(const uint32_t a, const uint8_t v)
{
	TRACE("write_unibus_byte[%08o]=%03o", a, v);
	if (a < m->get_memory_size())
		m->write_byte(a, v);
}