Main paging handler.
Imported-from: https://svn.code.sf.net/p/dosbox/code-0/dosbox/trunk@1119
This commit is contained in:
Sjoerd van der Berg
parent
a1993a714c
commit
93c6c0c803
1 changed files with 250 additions and 0 deletions
250
src/cpu/paging.cpp
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src/cpu/paging.cpp
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/*
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* Copyright (C) 2002-2003 The DOSBox Team
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Library General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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#include <stdlib.h>
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#include <assert.h>
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#include <string.h>
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#include "dosbox.h"
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#include "mem.h"
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#include "paging.h"
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#include "../hardware/vga.h"
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#define LINK_TOTAL (64*1024)
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static PageLink link_list[LINK_TOTAL];
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struct PagingBlock paging;
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class PageDirChange : public PageChange {
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public:
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PageDirChange(PageDirectory * mydir) { dir=mydir;}
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void Changed(PageLink * link,Bitu start,Bitu end) {
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start>>=2;end>>=2;
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for (;start<=end;start++) {
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dir->InvalidateTable(start);
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}
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}
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private:
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PageDirectory * dir;
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};
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class PageTableChange : public PageChange {
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public:
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PageTableChange(PageDirectory * mydir) { dir=mydir;}
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void Changed(PageLink * link,Bitu start,Bitu end) {
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start>>=2;end>>=2;
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for (;start<=end;start++) {
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dir->InvalidateLink(link->data.table,start);
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}
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}
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private:
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PageDirectory * dir;
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};
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PageDirectory::PageDirectory() {
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entry_init.data.dir=this;
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entry_init.type=ENTRY_INIT;
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link_init.read=0;
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link_init.write=0;
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link_init.entry=&entry_init;
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table_change = new PageTableChange(this);
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dir_change = new PageDirChange(this);
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}
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PageDirectory::~PageDirectory() {
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delete table_change;
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delete dir_change;
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}
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void PageDirectory::ClearDirectory(void) {
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Bitu i;
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for (i=0;i<1024*1024;i++) links[i]=&link_init;
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for (i=0;i<1024;i++) {
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tables[i]=0;
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}
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}
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void PageDirectory::SetBase(PhysPt page) {
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base_page=page;
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ClearDirectory();
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/* Setup handler for PageDirectory changes */
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link_dir=MEM_LinkPage(base_page,0);
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if (!link_dir) E_Exit("PageDirectory setup on illegal address");
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link_dir->data.dir=this;
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link_dir->change=dir_change;
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MEM_CheckLinks(link_dir->entry);
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}
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void PageDirectory::LinkPage(Bitu lin_page,Bitu phys_page) {
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if (links[lin_page] != &link_init) MEM_UnlinkPage(links[lin_page]);
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PageLink * link=MEM_LinkPage(phys_page,lin_page*4096);
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if (link) links[lin_page]=link;
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else links[lin_page]=&link_init;
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}
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bool PageDirectory::InitPage(Bitu lin_address) {
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Bitu lin_page=lin_address >> 12;
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Bitu table=lin_page >> 10;
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Bitu index=lin_page & 0x3ff;
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/* Check if there already is table linked */
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if (!tables[table]) {
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X86PageEntry table_entry;
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table_entry.load=phys_page_readd(base_page,0);
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if (!table_entry.block.p) {
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LOG(LOG_PAGING,LOG_ERROR)("NP TABLE");
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return false;
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}
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PageLink * link=MEM_LinkPage(table_entry.block.base,table_entry.block.base);
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if (!link) return false;
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link->data.table=table;
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link->change=table_change;
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MEM_CheckLinks(link->entry);
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tables[table]=link;
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}
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X86PageEntry entry;
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entry.load=phys_page_readd(tables[table]->lin_base,index);
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if (!entry.block.p) {
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LOG(LOG_PAGING,LOG_ERROR)("NP PAGE");
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return false;
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}
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PageLink * link=MEM_LinkPage(entry.block.base,lin_page*4096);
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if (!link) return false;
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links[lin_page]=link;
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return true;
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}
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bool PageDirectory::InitPageLinear(Bitu lin_address) {
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Bitu phys_page=lin_address >> 12;
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PageLink * link=MEM_LinkPage(phys_page,phys_page*4096);
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if (link) {
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/* Set the page entry in our table */
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links[phys_page]=link;
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return true;
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}
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return false;
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}
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void PageDirectory::InvalidateTable(Bitu table) {
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if (tables[table]) {
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MEM_UnlinkPage(tables[table]);
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tables[table]=0;
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for (Bitu i=(table*1024);i<(table+1)*1024;i++) {
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if (links[i]!=&link_init) {
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MEM_UnlinkPage(links[i]);
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links[i]=&link_init;
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}
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}
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}
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}
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void PageDirectory::InvalidateLink(Bitu table,Bitu index) {
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Bitu i=(table*1024)+index;
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if (links[i]!=&link_init) {
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MEM_UnlinkPage(links[i]);
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links[i]=&link_init;
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}
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}
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Bitu PAGING_GetDirBase(void) {
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return paging.cr3;
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}
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void PAGING_SetDirBase(Bitu cr3) {
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paging.cr3=cr3;
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Bitu base_page=cr3 >> 12;
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LOG_MSG("CR3:%X Base %X",cr3,base_page);
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if (paging.enabled) {
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/* Check if we already have this one cached */
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PageDirectory * dir=paging.cache;
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while (dir) {
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if (dir->base_page==base_page) {
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paging.dir=dir;
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return;
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}
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dir=dir->next;
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}
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/* Couldn't find cached directory, make a new one */
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dir=new PageDirectory();
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dir->next=paging.cache;
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paging.cache=dir;
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dir->SetBase(base_page);
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paging.dir=dir;
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}
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}
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void PAGING_Enable(bool enabled) {
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/* If paging is disable we work from a default paging table */
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if (paging.enabled==enabled) return;
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paging.enabled=enabled;
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if (!enabled) {
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LOG_MSG("Paging disabled");
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paging.dir=MEM_DefaultDirectory();
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} else {
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LOG_MSG("Paging enabled");
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PAGING_SetDirBase(paging.cr3);
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}
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}
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bool PAGING_Enabled(void) {
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return paging.enabled;
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}
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void PAGING_FreePageLink(PageLink * link) {
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MEM_UnlinkPage(link);
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PAGING_AddFreePageLink(link);
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}
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void PAGING_LinkPage(PageDirectory * dir,Bitu lin_page,Bitu phys_page) {
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PageLink * link=MEM_LinkPage(phys_page,lin_page*4096);
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/* Only replace if we can */
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if (link) {
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PAGING_FreePageLink(dir->links[lin_page]);
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dir->links[lin_page]=link;
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}
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}
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void PAGING_AddFreePageLink(PageLink * link) {
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link->read=0;
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link->write=0;
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link->change=0;
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link->next=paging.free_link;
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link->entry=0;
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paging.free_link=link;
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}
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PageLink * PAGING_GetFreePageLink(void) {
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PageLink * ret;
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if (paging.free_link) ret=paging.free_link;
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else E_Exit("PAGING:Ran out of PageEntries");
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paging.free_link=ret->next;
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ret->next=0;
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return ret;
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}
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void PAGING_Init(Section * sec) {
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Bitu i;
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/* Setup the free pages tables for fast page allocation */
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paging.cache=0;
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paging.free_link=0;
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for (i=0;i<LINK_TOTAL;i++) PAGING_AddFreePageLink(&link_list[i]);
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/* Setup default Page Directory, force it to update */
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paging.enabled=true;PAGING_Enable(false);
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}
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