src/io.js - emulators/v86 - Rivoreo Source Code Repositories

 "use strict";

 /**
  * The ISA IO bus
  * Devices register their ports here
  *
  * @constructor
  * @param {CPU} cpu
  */
 function IO(cpu)
 {
     /** @const */
     this.ports = [];

     /** @const @type {CPU} */
     this.cpu = cpu;

     for(var i = 0; i < 0x10000; i++)
     {
         this.ports[i] = this.create_empty_entry();
     }

     var memory_size = cpu.memory_size;

     for(var i = 0; (i << MMAP_BLOCK_BITS) < memory_size; i++)
     {
         // avoid sparse arrays
         cpu.memory_map_read8[i] = cpu.memory_map_write8[i] = undefined;
         cpu.memory_map_read32[i] = cpu.memory_map_write32[i] = undefined;
     }

     this.mmap_register(memory_size, 0x100000000 - memory_size,
         function(addr) {
             // read outside of the memory size
             dbg_log("Read from unmapped memory space, addr=" + h(addr >>> 0, 8), LOG_IO);
             return 0xFF;
         },
         function(addr, value) {
             // write outside of the memory size
             dbg_log("Write to unmapped memory space, addr=" + h(addr >>> 0, 8) + " value=" + h(value, 2), LOG_IO);
         },
         function(addr) {
             dbg_log("Read from unmapped memory space, addr=" + h(addr >>> 0, 8), LOG_IO);
             return -1;
         },
         function(addr, value) {
             dbg_log("Write to unmapped memory space, addr=" + h(addr >>> 0, 8) + " value=" + h(value >>> 0, 8), LOG_IO);
         }
     );
 }

 IO.prototype.create_empty_entry = function()
 {
     return {
         read8: this.empty_port_read8,
         read16: this.empty_port_read16,
         read32: this.empty_port_read32,

         write8: this.empty_port_write,
         write16: this.empty_port_write,
         write32: this.empty_port_write,

         device: undefined,
     };
 };

 IO.prototype.empty_port_read8 = function()
 {
     return 0xFF;
 };

 IO.prototype.empty_port_read16 = function()
 {
     return 0xFFFF;
 };

 IO.prototype.empty_port_read32 = function()
 {
     return -1;
 };

 IO.prototype.empty_port_write = function(x)
 {
 };


 /**
  * @param {number} port_addr
  * @param {Object} device
  * @param {function():number=} r8
  * @param {function():number=} r16
  * @param {function():number=} r32
  */
 IO.prototype.register_read = function(port_addr, device, r8, r16, r32)
 {
     dbg_assert(typeof port_addr === "number");
     dbg_assert(typeof device === "object");
     dbg_assert(!r8 || typeof r8 === "function");
     dbg_assert(!r16 || typeof r16 === "function");
     dbg_assert(!r32 || typeof r32 === "function");
     dbg_assert(r8 || r16 || r32);

     if(DEBUG)
     {
         var fail = function(n) {
             dbg_assert(false, "Overlapped read" + n + " " + h(port_addr, 4) + " (" + device.name + ")");
             return -1 >>> (32 - n) | 0;
         };
         if(!r8) r8 = fail.bind(this, 8);
         if(!r16) r16 = fail.bind(this, 16);
         if(!r32) r32 = fail.bind(this, 32);
     }

     if(r8) this.ports[port_addr].read8 = r8;
     if(r16) this.ports[port_addr].read16 = r16;
     if(r32) this.ports[port_addr].read32 = r32;
     this.ports[port_addr].device = device;
 };

 /**
  * @param {number} port_addr
  * @param {Object} device
  * @param {function(number)=} w8
  * @param {function(number)=} w16
  * @param {function(number)=} w32
  */
 IO.prototype.register_write = function(port_addr, device, w8, w16, w32)
 {
     dbg_assert(typeof port_addr === "number");
     dbg_assert(typeof device === "object");
     dbg_assert(!w8 || typeof w8 === "function");
     dbg_assert(!w16 || typeof w16 === "function");
     dbg_assert(!w32 || typeof w32 === "function");
     dbg_assert(w8 || w16 || w32);

     if(DEBUG)
     {
         var fail = function(n) {
             dbg_assert(false, "Overlapped write" + n + " " + h(port_addr) + " (" + device.name + ")");
         };
         if(!w8) w8 = fail.bind(this, 8);
         if(!w16) w16 = fail.bind(this, 16);
         if(!w32) w32 = fail.bind(this, 32);
     }

     if(w8) this.ports[port_addr].write8 = w8;
     if(w16) this.ports[port_addr].write16 = w16;
     if(w32) this.ports[port_addr].write32 = w32;
     this.ports[port_addr].device = device;
 };

 /**
  * > Any two consecutive 8-bit ports can be treated as a 16-bit port;
  * > and four consecutive 8-bit ports can be treated as a 32-bit port
  * > http://css.csail.mit.edu/6.858/2012/readings/i386/s08_01.htm
  *
  * This info is not correct for all ports, but handled by the following functions
  *
  * Register the write of 2 or 4 consecutive 8-bit ports, 1 or 2 16-bit
  * ports and 0 or 1 32-bit ports
  *
  * @param {number} port_addr
  * @param {!Object} device
  * @param {function():number} r8_1
  * @param {function():number} r8_2
  * @param {function():number=} r8_3
  * @param {function():number=} r8_4
  */
 IO.prototype.register_read_consecutive = function(port_addr, device, r8_1, r8_2, r8_3, r8_4)
 {
     dbg_assert(arguments.length === 4 || arguments.length === 6);

     function r16_1()
     {
         return r8_1.call(this) |
                 r8_2.call(this) << 8;
     }
     function r16_2()
     {
         return r8_3.call(this) |
                 r8_4.call(this) << 8;
     }
     function r32()
     {
         return r8_1.call(this) |
                 r8_2.call(this) << 8 |
                 r8_3.call(this) << 16 |
                 r8_4.call(this) << 24;
     }

     if(r8_3 && r8_4)
     {
         this.register_read(port_addr, device, r8_1, r16_1, r32);
         this.register_read(port_addr + 1, device, r8_2);
         this.register_read(port_addr + 2, device, r8_3, r16_2);
         this.register_read(port_addr + 3, device, r8_4);
     }
     else
     {
         this.register_read(port_addr, device, r8_1, r16_1);
         this.register_read(port_addr + 1, device, r8_2);
     }
 };

 /**
  * @param {number} port_addr
  * @param {!Object} device
  * @param {function(number)} w8_1
  * @param {function(number)} w8_2
  * @param {function(number)=} w8_3
  * @param {function(number)=} w8_4
  */
 IO.prototype.register_write_consecutive = function(port_addr, device, w8_1, w8_2, w8_3, w8_4)
 {
     dbg_assert(arguments.length === 4 || arguments.length === 6);

     function w16_1(data)
     {
         w8_1.call(this, data & 0xFF);
         w8_2.call(this, data >> 8 & 0xFF);
     }
     function w16_2(data)
     {
         w8_3.call(this, data & 0xFF);
         w8_4.call(this, data >> 8 & 0xFF);
     }
     function w32(data)
     {
         w8_1.call(this, data & 0xFF);
         w8_2.call(this, data >> 8 & 0xFF);
         w8_3.call(this, data >> 16 & 0xFF);
         w8_4.call(this, data >>> 24);
     }

     if(w8_3 && w8_4)
     {
         this.register_write(port_addr,     device, w8_1, w16_1, w32);
         this.register_write(port_addr + 1, device, w8_2);
         this.register_write(port_addr + 2, device, w8_3, w16_2);
         this.register_write(port_addr + 3, device, w8_4);
     }
     else
     {
         this.register_write(port_addr,     device, w8_1, w16_1);
         this.register_write(port_addr + 1, device, w8_2);
     }
 };

 IO.prototype.in_mmap_range = function(start, count)
 {
     start >>>= 0;
     count >>>= 0;

     var end = start + count;

     if(end >= this.cpu.memory_size)
     {
         return true;
     }

     //dbg_log("in_mmap_range start=" + start + " count=" + count);
     start &= ~(MMAP_BLOCK_SIZE - 1);

     while(start < end)
     {
         if(this.cpu.in_mapped_range(start))
         {
             return true;
         }

         start += MMAP_BLOCK_SIZE;
     }

     return false;
 };

 IO.prototype.mmap_read32_shim = function(addr)
 {
     var aligned_addr = addr >>> MMAP_BLOCK_BITS;
     var fn = this.cpu.memory_map_read8[aligned_addr];

     return fn(addr) | fn(addr + 1) << 8 |
             fn(addr + 2) << 16 | fn(addr + 3) << 24;
 };

 IO.prototype.mmap_write32_shim = function(addr, value)
 {
     var aligned_addr = addr >>> MMAP_BLOCK_BITS;
     var fn = this.cpu.memory_map_write8[aligned_addr];

     fn(addr, value & 0xFF);
     fn(addr + 1, value >> 8 & 0xFF);
     fn(addr + 2, value >> 16 & 0xFF);
     fn(addr + 3, value >>> 24);
 };

 /**
  * @param {number} addr
  * @param {number} size
  * @param {*} read_func8
  * @param {*} write_func8
  * @param {*=} read_func32
  * @param {*=} write_func32
  */
 IO.prototype.mmap_register = function(addr, size, read_func8, write_func8, read_func32, write_func32)
 {
     dbg_log("mmap_register addr=" + h(addr >>> 0, 8) + " size=" + h(size, 8), LOG_IO);

     dbg_assert((addr & MMAP_BLOCK_SIZE - 1) === 0);
     dbg_assert(size && (size & MMAP_BLOCK_SIZE - 1) === 0);

     if(!read_func32)
         read_func32 = this.mmap_read32_shim.bind(this);

     if(!write_func32)
         write_func32 = this.mmap_write32_shim.bind(this);

     var aligned_addr = addr >>> MMAP_BLOCK_BITS;

     for(; size > 0; aligned_addr++)
     {
         this.cpu.memory_map_read8[aligned_addr] = read_func8;
         this.cpu.memory_map_write8[aligned_addr] = write_func8;
         this.cpu.memory_map_read32[aligned_addr] = read_func32;
         this.cpu.memory_map_write32[aligned_addr] = write_func32;

         size -= MMAP_BLOCK_SIZE;
     }
 };


 IO.prototype.port_write8 = function(port_addr, data)
 {
     var entry = this.ports[port_addr];

     if(entry.write8 === this.empty_port_write || LOG_ALL_IO)
     {
         dbg_log(
             "write8 port #" + h(port_addr, 4) + " <- " + h(data, 2) + this.get_port_description(port_addr),
             LOG_IO
         );
     }
     return entry.write8.call(entry.device, data);
 };

 IO.prototype.port_write16 = function(port_addr, data)
 {
     var entry = this.ports[port_addr];

     if(entry.write16 === this.empty_port_write || LOG_ALL_IO)
     {
         dbg_log(
             "write16 port #" + h(port_addr, 4) + " <- " + h(data, 4) + this.get_port_description(port_addr),
             LOG_IO
         );
     }
     return entry.write16.call(entry.device, data);
 };

 IO.prototype.port_write32 = function(port_addr, data)
 {
     var entry = this.ports[port_addr];

     if(entry.write32 === this.empty_port_write || LOG_ALL_IO)
     {
         dbg_log(
             "write32 port #" + h(port_addr, 4) + " <- " + h(data >>> 0, 8) + this.get_port_description(port_addr),
             LOG_IO
         );
     }
     return entry.write32.call(entry.device, data);
 };

 IO.prototype.port_read8 = function(port_addr)
 {
     var entry = this.ports[port_addr];

     if(entry.read8 === this.empty_port_read8 || LOG_ALL_IO)
     {
         dbg_log(
             "read8 port  #" + h(port_addr, 4) + this.get_port_description(port_addr),
             LOG_IO
         );
     }
     var value = entry.read8.call(entry.device);
     dbg_assert(value < 0x100, "8 bit port returned large value: " + h(port_addr));
     return value;
 };

 IO.prototype.port_read16 = function(port_addr)
 {
     var entry = this.ports[port_addr];

     if(entry.read16 === this.empty_port_read16 || LOG_ALL_IO)
     {
         dbg_log(
             "read16 port  #" + h(port_addr, 4) + this.get_port_description(port_addr),
             LOG_IO
         );
     }
     var value = entry.read16.call(entry.device);
     dbg_assert(value < 0x10000 && value >= 0, "16 bit port returned large value: " + h(port_addr));
     return value;
 };

 IO.prototype.port_read32 = function(port_addr)
 {
     var entry = this.ports[port_addr];

     if(entry.read32 === this.empty_port_read32 || LOG_ALL_IO)
     {
         dbg_log(
             "read32 port  #" + h(port_addr, 4) + this.get_port_description(port_addr),
             LOG_IO
         );
     }
     var value = entry.read32.call(entry.device);
     dbg_assert((value | 0) === value);
     return value;
 };

 // via seabios ioport.h
 var debug_port_list = {
     0x0004: "PORT_DMA_ADDR_2",
     0x0005: "PORT_DMA_CNT_2",
     0x000a: "PORT_DMA1_MASK_REG",
     0x000b: "PORT_DMA1_MODE_REG",
     0x000c: "PORT_DMA1_CLEAR_FF_REG",
     0x000d: "PORT_DMA1_MASTER_CLEAR",
     0x0020: "PORT_PIC1_CMD",
     0x0021: "PORT_PIC1_DATA",
     0x0040: "PORT_PIT_COUNTER0",
     0x0041: "PORT_PIT_COUNTER1",
     0x0042: "PORT_PIT_COUNTER2",
     0x0043: "PORT_PIT_MODE",
     0x0060: "PORT_PS2_DATA",
     0x0061: "PORT_PS2_CTRLB",
     0x0064: "PORT_PS2_STATUS",
     0x0070: "PORT_CMOS_INDEX",
     0x0071: "PORT_CMOS_DATA",
     0x0080: "PORT_DIAG",
     0x0081: "PORT_DMA_PAGE_2",
     0x0092: "PORT_A20",
     0x00a0: "PORT_PIC2_CMD",
     0x00a1: "PORT_PIC2_DATA",
     0x00b2: "PORT_SMI_CMD",
     0x00b3: "PORT_SMI_STATUS",
     0x00d4: "PORT_DMA2_MASK_REG",
     0x00d6: "PORT_DMA2_MODE_REG",
     0x00da: "PORT_DMA2_MASTER_CLEAR",
     0x00f0: "PORT_MATH_CLEAR",
     0x0170: "PORT_ATA2_CMD_BASE",
     0x01f0: "PORT_ATA1_CMD_BASE",
     0x0278: "PORT_LPT2",
     0x02e8: "PORT_SERIAL4",
     0x02f8: "PORT_SERIAL2",
     0x0374: "PORT_ATA2_CTRL_BASE",
     0x0378: "PORT_LPT1",
     0x03e8: "PORT_SERIAL3",
     //0x03f4: "PORT_ATA1_CTRL_BASE",
     0x03f0: "PORT_FD_BASE",
     0x03f2: "PORT_FD_DOR",
     0x03f4: "PORT_FD_STATUS",
     0x03f5: "PORT_FD_DATA",
     0x03f6: "PORT_HD_DATA",
     0x03f7: "PORT_FD_DIR",
     0x03f8: "PORT_SERIAL1",
     0x0cf8: "PORT_PCI_CMD",
     0x0cf9: "PORT_PCI_REBOOT",
     0x0cfc: "PORT_PCI_DATA",
     0x0402: "PORT_BIOS_DEBUG",
     0x0510: "PORT_QEMU_CFG_CTL",
     0x0511: "PORT_QEMU_CFG_DATA",
     0xb000: "PORT_ACPI_PM_BASE",
     0xb100: "PORT_SMB_BASE",
     0x8900: "PORT_BIOS_APM"
 };

 IO.prototype.get_port_description = function(addr)
 {
     if(debug_port_list[addr])
     {
         return "  (" + debug_port_list[addr] + ")";
     }
     else
     {
         return "";
     }
 };
	"use strict";

	/**
	* The ISA IO bus
	* Devices register their ports here
	*
	* @constructor
	* @param {CPU} cpu
	*/
	function IO(cpu)
	{
	/** @const */
	this.ports = [];

	/** @const @type {CPU} */
	this.cpu = cpu;

	for(var i = 0; i < 0x10000; i++)
	{
	this.ports[i] = this.create_empty_entry();
	}

	var memory_size = cpu.memory_size;

	for(var i = 0; (i << MMAP_BLOCK_BITS) < memory_size; i++)
	{
	// avoid sparse arrays
	cpu.memory_map_read8[i] = cpu.memory_map_write8[i] = undefined;
	cpu.memory_map_read32[i] = cpu.memory_map_write32[i] = undefined;
	}

	this.mmap_register(memory_size, 0x100000000 - memory_size,
	function(addr) {
	// read outside of the memory size
	dbg_log("Read from unmapped memory space, addr=" + h(addr >>> 0, 8), LOG_IO);
	return 0xFF;
	},
	function(addr, value) {
	// write outside of the memory size
	dbg_log("Write to unmapped memory space, addr=" + h(addr >>> 0, 8) + " value=" + h(value, 2), LOG_IO);
	},
	function(addr) {
	dbg_log("Read from unmapped memory space, addr=" + h(addr >>> 0, 8), LOG_IO);
	return -1;
	},
	function(addr, value) {
	dbg_log("Write to unmapped memory space, addr=" + h(addr >>> 0, 8) + " value=" + h(value >>> 0, 8), LOG_IO);
	}
	);
	}

	IO.prototype.create_empty_entry = function()
	{
	return {
	read8: this.empty_port_read8,
	read16: this.empty_port_read16,
	read32: this.empty_port_read32,

	write8: this.empty_port_write,
	write16: this.empty_port_write,
	write32: this.empty_port_write,

	device: undefined,
	};
	};

	IO.prototype.empty_port_read8 = function()
	{
	return 0xFF;
	};

	IO.prototype.empty_port_read16 = function()
	{
	return 0xFFFF;
	};

	IO.prototype.empty_port_read32 = function()
	{
	return -1;
	};

	IO.prototype.empty_port_write = function(x)
	{
	};


	/**
	* @param {number} port_addr
	* @param {Object} device
	* @param {function():number=} r8
	* @param {function():number=} r16
	* @param {function():number=} r32
	*/
	IO.prototype.register_read = function(port_addr, device, r8, r16, r32)
	{
	dbg_assert(typeof port_addr === "number");
	dbg_assert(typeof device === "object");
	dbg_assert(!r8 \|\| typeof r8 === "function");
	dbg_assert(!r16 \|\| typeof r16 === "function");
	dbg_assert(!r32 \|\| typeof r32 === "function");
	dbg_assert(r8 \|\| r16 \|\| r32);

	if(DEBUG)
	{
	var fail = function(n) {
	dbg_assert(false, "Overlapped read" + n + " " + h(port_addr, 4) + " (" + device.name + ")");
	return -1 >>> (32 - n) \| 0;
	};
	if(!r8) r8 = fail.bind(this, 8);
	if(!r16) r16 = fail.bind(this, 16);
	if(!r32) r32 = fail.bind(this, 32);
	}

	if(r8) this.ports[port_addr].read8 = r8;
	if(r16) this.ports[port_addr].read16 = r16;
	if(r32) this.ports[port_addr].read32 = r32;
	this.ports[port_addr].device = device;
	};

	/**
	* @param {number} port_addr
	* @param {Object} device
	* @param {function(number)=} w8
	* @param {function(number)=} w16
	* @param {function(number)=} w32
	*/
	IO.prototype.register_write = function(port_addr, device, w8, w16, w32)
	{
	dbg_assert(typeof port_addr === "number");
	dbg_assert(typeof device === "object");
	dbg_assert(!w8 \|\| typeof w8 === "function");
	dbg_assert(!w16 \|\| typeof w16 === "function");
	dbg_assert(!w32 \|\| typeof w32 === "function");
	dbg_assert(w8 \|\| w16 \|\| w32);

	if(DEBUG)
	{
	var fail = function(n) {
	dbg_assert(false, "Overlapped write" + n + " " + h(port_addr) + " (" + device.name + ")");
	};
	if(!w8) w8 = fail.bind(this, 8);
	if(!w16) w16 = fail.bind(this, 16);
	if(!w32) w32 = fail.bind(this, 32);
	}

	if(w8) this.ports[port_addr].write8 = w8;
	if(w16) this.ports[port_addr].write16 = w16;
	if(w32) this.ports[port_addr].write32 = w32;
	this.ports[port_addr].device = device;
	};

	/**
	* > Any two consecutive 8-bit ports can be treated as a 16-bit port;
	* > and four consecutive 8-bit ports can be treated as a 32-bit port
	* > http://css.csail.mit.edu/6.858/2012/readings/i386/s08_01.htm
	*
	* This info is not correct for all ports, but handled by the following functions
	*
	* Register the write of 2 or 4 consecutive 8-bit ports, 1 or 2 16-bit
	* ports and 0 or 1 32-bit ports
	*
	* @param {number} port_addr
	* @param {!Object} device
	* @param {function():number} r8_1
	* @param {function():number} r8_2
	* @param {function():number=} r8_3
	* @param {function():number=} r8_4
	*/
	IO.prototype.register_read_consecutive = function(port_addr, device, r8_1, r8_2, r8_3, r8_4)
	{
	dbg_assert(arguments.length === 4 \|\| arguments.length === 6);

	function r16_1()
	{
	return r8_1.call(this) \|
	r8_2.call(this) << 8;
	}
	function r16_2()
	{
	return r8_3.call(this) \|
	r8_4.call(this) << 8;
	}
	function r32()
	{
	return r8_1.call(this) \|
	r8_2.call(this) << 8 \|
	r8_3.call(this) << 16 \|
	r8_4.call(this) << 24;
	}

	if(r8_3 && r8_4)
	{
	this.register_read(port_addr, device, r8_1, r16_1, r32);
	this.register_read(port_addr + 1, device, r8_2);
	this.register_read(port_addr + 2, device, r8_3, r16_2);
	this.register_read(port_addr + 3, device, r8_4);
	}
	else
	{
	this.register_read(port_addr, device, r8_1, r16_1);
	this.register_read(port_addr + 1, device, r8_2);
	}
	};

	/**
	* @param {number} port_addr
	* @param {!Object} device
	* @param {function(number)} w8_1
	* @param {function(number)} w8_2
	* @param {function(number)=} w8_3
	* @param {function(number)=} w8_4
	*/
	IO.prototype.register_write_consecutive = function(port_addr, device, w8_1, w8_2, w8_3, w8_4)
	{
	dbg_assert(arguments.length === 4 \|\| arguments.length === 6);

	function w16_1(data)
	{
	w8_1.call(this, data & 0xFF);
	w8_2.call(this, data >> 8 & 0xFF);
	}
	function w16_2(data)
	{
	w8_3.call(this, data & 0xFF);
	w8_4.call(this, data >> 8 & 0xFF);
	}
	function w32(data)
	{
	w8_1.call(this, data & 0xFF);
	w8_2.call(this, data >> 8 & 0xFF);
	w8_3.call(this, data >> 16 & 0xFF);
	w8_4.call(this, data >>> 24);
	}

	if(w8_3 && w8_4)
	{
	this.register_write(port_addr, device, w8_1, w16_1, w32);
	this.register_write(port_addr + 1, device, w8_2);
	this.register_write(port_addr + 2, device, w8_3, w16_2);
	this.register_write(port_addr + 3, device, w8_4);
	}
	else
	{
	this.register_write(port_addr, device, w8_1, w16_1);
	this.register_write(port_addr + 1, device, w8_2);
	}
	};

	IO.prototype.in_mmap_range = function(start, count)
	{
	start >>>= 0;
	count >>>= 0;

	var end = start + count;

	if(end >= this.cpu.memory_size)
	{
	return true;
	}

	//dbg_log("in_mmap_range start=" + start + " count=" + count);
	start &= ~(MMAP_BLOCK_SIZE - 1);

	while(start < end)
	{
	if(this.cpu.in_mapped_range(start))
	{
	return true;
	}

	start += MMAP_BLOCK_SIZE;
	}

	return false;
	};

	IO.prototype.mmap_read32_shim = function(addr)
	{
	var aligned_addr = addr >>> MMAP_BLOCK_BITS;
	var fn = this.cpu.memory_map_read8[aligned_addr];

	return fn(addr) \| fn(addr + 1) << 8 \|
	fn(addr + 2) << 16 \| fn(addr + 3) << 24;
	};

	IO.prototype.mmap_write32_shim = function(addr, value)
	{
	var aligned_addr = addr >>> MMAP_BLOCK_BITS;
	var fn = this.cpu.memory_map_write8[aligned_addr];

	fn(addr, value & 0xFF);
	fn(addr + 1, value >> 8 & 0xFF);
	fn(addr + 2, value >> 16 & 0xFF);
	fn(addr + 3, value >>> 24);
	};

	/**
	* @param {number} addr
	* @param {number} size
	* @param {*} read_func8
	* @param {*} write_func8
	* @param {*=} read_func32
	* @param {*=} write_func32
	*/
	IO.prototype.mmap_register = function(addr, size, read_func8, write_func8, read_func32, write_func32)
	{
	dbg_log("mmap_register addr=" + h(addr >>> 0, 8) + " size=" + h(size, 8), LOG_IO);

	dbg_assert((addr & MMAP_BLOCK_SIZE - 1) === 0);
	dbg_assert(size && (size & MMAP_BLOCK_SIZE - 1) === 0);

	if(!read_func32)
	read_func32 = this.mmap_read32_shim.bind(this);

	if(!write_func32)
	write_func32 = this.mmap_write32_shim.bind(this);

	var aligned_addr = addr >>> MMAP_BLOCK_BITS;

	for(; size > 0; aligned_addr++)
	{
	this.cpu.memory_map_read8[aligned_addr] = read_func8;
	this.cpu.memory_map_write8[aligned_addr] = write_func8;
	this.cpu.memory_map_read32[aligned_addr] = read_func32;
	this.cpu.memory_map_write32[aligned_addr] = write_func32;

	size -= MMAP_BLOCK_SIZE;
	}
	};


	IO.prototype.port_write8 = function(port_addr, data)
	{
	var entry = this.ports[port_addr];

	if(entry.write8 === this.empty_port_write \|\| LOG_ALL_IO)
	{
	dbg_log(
	"write8 port #" + h(port_addr, 4) + " <- " + h(data, 2) + this.get_port_description(port_addr),
	LOG_IO
	);
	}
	return entry.write8.call(entry.device, data);
	};

	IO.prototype.port_write16 = function(port_addr, data)
	{
	var entry = this.ports[port_addr];

	if(entry.write16 === this.empty_port_write \|\| LOG_ALL_IO)
	{
	dbg_log(
	"write16 port #" + h(port_addr, 4) + " <- " + h(data, 4) + this.get_port_description(port_addr),
	LOG_IO
	);
	}
	return entry.write16.call(entry.device, data);
	};

	IO.prototype.port_write32 = function(port_addr, data)
	{
	var entry = this.ports[port_addr];

	if(entry.write32 === this.empty_port_write \|\| LOG_ALL_IO)
	{
	dbg_log(
	"write32 port #" + h(port_addr, 4) + " <- " + h(data >>> 0, 8) + this.get_port_description(port_addr),
	LOG_IO
	);
	}
	return entry.write32.call(entry.device, data);
	};

	IO.prototype.port_read8 = function(port_addr)
	{
	var entry = this.ports[port_addr];

	if(entry.read8 === this.empty_port_read8 \|\| LOG_ALL_IO)
	{
	dbg_log(
	"read8 port #" + h(port_addr, 4) + this.get_port_description(port_addr),
	LOG_IO
	);
	}
	var value = entry.read8.call(entry.device);
	dbg_assert(value < 0x100, "8 bit port returned large value: " + h(port_addr));
	return value;
	};

	IO.prototype.port_read16 = function(port_addr)
	{
	var entry = this.ports[port_addr];

	if(entry.read16 === this.empty_port_read16 \|\| LOG_ALL_IO)
	{
	dbg_log(
	"read16 port #" + h(port_addr, 4) + this.get_port_description(port_addr),
	LOG_IO
	);
	}
	var value = entry.read16.call(entry.device);
	dbg_assert(value < 0x10000 && value >= 0, "16 bit port returned large value: " + h(port_addr));
	return value;
	};

	IO.prototype.port_read32 = function(port_addr)
	{
	var entry = this.ports[port_addr];

	if(entry.read32 === this.empty_port_read32 \|\| LOG_ALL_IO)
	{
	dbg_log(
	"read32 port #" + h(port_addr, 4) + this.get_port_description(port_addr),
	LOG_IO
	);
	}
	var value = entry.read32.call(entry.device);
	dbg_assert((value \| 0) === value);
	return value;
	};

	// via seabios ioport.h
	var debug_port_list = {
	0x0004: "PORT_DMA_ADDR_2",
	0x0005: "PORT_DMA_CNT_2",
	0x000a: "PORT_DMA1_MASK_REG",
	0x000b: "PORT_DMA1_MODE_REG",
	0x000c: "PORT_DMA1_CLEAR_FF_REG",
	0x000d: "PORT_DMA1_MASTER_CLEAR",
	0x0020: "PORT_PIC1_CMD",
	0x0021: "PORT_PIC1_DATA",
	0x0040: "PORT_PIT_COUNTER0",
	0x0041: "PORT_PIT_COUNTER1",
	0x0042: "PORT_PIT_COUNTER2",
	0x0043: "PORT_PIT_MODE",
	0x0060: "PORT_PS2_DATA",
	0x0061: "PORT_PS2_CTRLB",
	0x0064: "PORT_PS2_STATUS",
	0x0070: "PORT_CMOS_INDEX",
	0x0071: "PORT_CMOS_DATA",
	0x0080: "PORT_DIAG",
	0x0081: "PORT_DMA_PAGE_2",
	0x0092: "PORT_A20",
	0x00a0: "PORT_PIC2_CMD",
	0x00a1: "PORT_PIC2_DATA",
	0x00b2: "PORT_SMI_CMD",
	0x00b3: "PORT_SMI_STATUS",
	0x00d4: "PORT_DMA2_MASK_REG",
	0x00d6: "PORT_DMA2_MODE_REG",
	0x00da: "PORT_DMA2_MASTER_CLEAR",
	0x00f0: "PORT_MATH_CLEAR",
	0x0170: "PORT_ATA2_CMD_BASE",
	0x01f0: "PORT_ATA1_CMD_BASE",
	0x0278: "PORT_LPT2",
	0x02e8: "PORT_SERIAL4",
	0x02f8: "PORT_SERIAL2",
	0x0374: "PORT_ATA2_CTRL_BASE",
	0x0378: "PORT_LPT1",
	0x03e8: "PORT_SERIAL3",
	//0x03f4: "PORT_ATA1_CTRL_BASE",
	0x03f0: "PORT_FD_BASE",
	0x03f2: "PORT_FD_DOR",
	0x03f4: "PORT_FD_STATUS",
	0x03f5: "PORT_FD_DATA",
	0x03f6: "PORT_HD_DATA",
	0x03f7: "PORT_FD_DIR",
	0x03f8: "PORT_SERIAL1",
	0x0cf8: "PORT_PCI_CMD",
	0x0cf9: "PORT_PCI_REBOOT",
	0x0cfc: "PORT_PCI_DATA",
	0x0402: "PORT_BIOS_DEBUG",
	0x0510: "PORT_QEMU_CFG_CTL",
	0x0511: "PORT_QEMU_CFG_DATA",
	0xb000: "PORT_ACPI_PM_BASE",
	0xb100: "PORT_SMB_BASE",
	0x8900: "PORT_BIOS_APM"
	};

	IO.prototype.get_port_description = function(addr)
	{
	if(debug_port_list[addr])
	{
	return " (" + debug_port_list[addr] + ")";
	}
	else
	{
	return "";
	}
	};