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a20 implementation (disabled by default)

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copy 2016-01-23 00:13:21 +01:00
parent fd14f0232d
commit 5afaf634d7
1 changed files with 21 additions and 0 deletions
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21
src/memory.js
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@ -1,5 +1,15 @@
"use strict";
/** @const */
var A20_MASK = ~(1 << 20);
/** @const */
var A20_MASK16 = ~(1 << 20 - 1);
/** @const */
var A20_MASK32 = ~(1 << 20 - 2);
/** @const */
var USE_A20 = false;
/**
* @constructor
* @param {number} memory_size
@ -40,6 +50,8 @@ function Memory(memory_size, no_alloc)
this.mem16 = new Uint16Array(buffer);
this.mem32s = new Int32Array(buffer);
}
this.a20_enabled = true;
};
Memory.prototype.get_state = function()
@ -133,6 +145,7 @@ Memory.prototype.mmap_write32 = function(addr, value)
Memory.prototype.read8 = function(addr)
{
this.debug_read(addr, 1);
if(USE_A20 && !this.a20_enabled) addr &= A20_MASK;
if(this.memory_map_registered[addr >>> MMAP_BLOCK_BITS])
{
@ -150,6 +163,7 @@ Memory.prototype.read8 = function(addr)
Memory.prototype.read16 = function(addr)
{
this.debug_read(addr, 2);
if(USE_A20 && !this.a20_enabled) addr &= A20_MASK;
if(this.memory_map_registered[addr >>> MMAP_BLOCK_BITS])
{
@ -168,6 +182,7 @@ Memory.prototype.read_aligned16 = function(addr)
{
dbg_assert(addr >= 0 && addr < 0x80000000);
this.debug_read(addr << 1, 2);
if(USE_A20 && !this.a20_enabled) addr &= A20_MASK16;
if(this.memory_map_registered[addr >>> MMAP_BLOCK_BITS - 1])
{
@ -185,6 +200,7 @@ Memory.prototype.read_aligned16 = function(addr)
Memory.prototype.read32s = function(addr)
{
this.debug_read(addr, 4);
if(USE_A20 && !this.a20_enabled) addr &= A20_MASK;
if(this.memory_map_registered[addr >>> MMAP_BLOCK_BITS])
{
@ -222,6 +238,7 @@ Memory.prototype.read_aligned32 = function(addr)
Memory.prototype.write8 = function(addr, value)
{
this.debug_write(addr, 1, value);
if(USE_A20 && !this.a20_enabled) addr &= A20_MASK;
var page = addr >>> MMAP_BLOCK_BITS;
@ -244,6 +261,7 @@ Memory.prototype.write8 = function(addr, value)
Memory.prototype.write16 = function(addr, value)
{
this.debug_write(addr, 2, value);
if(USE_A20 && !this.a20_enabled) addr &= A20_MASK;
var page = addr >>> MMAP_BLOCK_BITS;
@ -272,6 +290,7 @@ Memory.prototype.write_aligned16 = function(addr, value)
{
dbg_assert(addr >= 0 && addr < 0x80000000);
this.debug_write(addr << 1, 2, value);
if(USE_A20 && !this.a20_enabled) addr &= A20_MASK16;
var page = addr >>> MMAP_BLOCK_BITS - 1;
@ -294,6 +313,7 @@ Memory.prototype.write_aligned16 = function(addr, value)
Memory.prototype.write32 = function(addr, value)
{
this.debug_write(addr, 4, value);
if(USE_A20 && !this.a20_enabled) addr &= A20_MASK;
var page = addr >>> MMAP_BLOCK_BITS;
@ -320,6 +340,7 @@ Memory.prototype.write_aligned32 = function(addr, value)
{
dbg_assert(addr >= 0 && addr < 0x40000000);
this.debug_write(addr << 2, 4, value);
if(USE_A20 && !this.a20_enabled) addr &= A20_MASK32;
var page = addr >>> MMAP_BLOCK_BITS - 2;