scummvm/sword2/memory.cpp
Jonathan Gray f020d28b5e bs2
svn-id: r9211
2003-07-28 01:44:38 +00:00

545 lines
19 KiB
C++

/* Copyright (C) 1994-2003 Revolution Software Ltd
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* $Header$
*/
//memory manager - "remember, it's not good to leave memory locked for a moment longer than necessary" Tony
// "actually, in a sequential system theoretically you never need to lock any memory!" Chris ;)
//
// This is a very simple implementation but I see little advantage to being any cleverer
// with the coding - i could have put the mem blocks before the defined blocks instead
// of in an array and then used pointers to child/parent blocks. But why bother? I've Kept it simple.
// When it needs updating or customising it will be accessable to anyone who looks at it.
// *doesn't have a purgeable/age consituant yet - if anyone wants this then I'll add it in.
// MemMan v1.1
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include "driver/driver96.h"
#include "console.h"
#include "debug.h"
#include "memory.h"
#include "resman.h"
uint32 total_blocks;
uint32 base_mem_block;
uint32 total_free_memory;
uint8 *free_memman; //address of init malloc to be freed later
//#define MEMDEBUG 1
mem mem_list[MAX_mem_blocks]; //list of defined memory handles - each representing a block of memory.
int32 VirtualDefrag( uint32 size ); // Used to determine if the required size can be obtained if the defragger is allowed to run.
int32 suggestedStart = 0; // Start position of the Defragger as indicated by its sister VirtualDefrag.
//------------------------------------------------------------------------------------
//------------------------------------------------------------------------------------
void Close_memory_manager(void) //Tony2Oct96
{
//unlock our supposedly locked in memory
VirtualUnlock(free_memman, total_free_memory);
free(free_memman);
}
//------------------------------------------------------------------------------------
void Init_memory_manager(void) //Tony9April96
{
uint32 j;
uint8 *memory_base;
//BOOL res;
MEMORYSTATUS memo;
//find out how much actual physical RAM this computer has
GlobalMemoryStatus(&memo);
//now decide how much to grab - 8MB computer are super critical
if (memo.dwTotalPhys<=(8000*1024)) //if 8MB or less :-O
total_free_memory=4500*1024; //4.5MB
else if (memo.dwTotalPhys<=(12000*1024)) //if 8MB or less :-O
total_free_memory=8000*1024; //8MB
else if (memo.dwTotalPhys<=(16000*1024)) //if 16MB or less :-)
total_free_memory=10000*1024; //10MB
else //:-)) loads of RAM
total_free_memory=12000*1024; //12MB
Zdebug("MEM = %d", memo.dwTotalPhys);
Zdebug("Sword 2 grabbed %dk", total_free_memory/1024);
//malloc memory and adjust for long boundaries
memory_base = (uint8 *) malloc(total_free_memory);
if (!memory_base) //could not grab the memory
{
Zdebug("couldn't malloc %d in Init_memory_manager", total_free_memory);
ExitWithReport("Init_memory_manager() couldn't malloc %d bytes [line=%d file=%s]",total_free_memory,__LINE__,__FILE__);
}
free_memman = memory_base; //the original malloc address
//force to long word boundary
memory_base+=3;
memory_base = (uint8 *)((uint32)memory_base & 0xfffffffc); // ** was (int)memory_base
// total_free_memory-=3; //play safe
//set all but first handle to unused
for (j=1;j<MAX_mem_blocks;j++)
mem_list[j].state=MEM_null;
total_blocks=1; //total used (free, locked or floating)
mem_list[0].ad = memory_base;
mem_list[0].state= MEM_free;
mem_list[0].age=0;
mem_list[0].size=total_free_memory;
mem_list[0].parent=-1; //we are base - for now
mem_list[0].child=-1; //we are the end as well
mem_list[0].uid=UID_memman; //init id
base_mem_block=0; //for now
//supposedly this will stop the memory swapping out?? Well, as much as we're allowed
// res=VirtualLock(free_memman, total_free_memory);
// if (res!=TRUE)
// Zdebug(" *VirtualLock failed");
}
//------------------------------------------------------------------------------------
mem *Talloc(uint32 size, uint32 type, uint32 unique_id) //Tony10Apr96
{
//allocate a block of memory - locked or float
// returns 0 if fails to allocate the memory
// or a pointer to a mem structure
int32 nu_block;
uint32 spawn=0;
uint32 slack;
//we must first round the size UP to a dword, so subsequent blocks will start dword alligned
size+=3; //move up
size &= 0xfffffffc; //and back down to boundary
//find a free block large enough
if ( (nu_block = Defrag_mem(size))==-1) //the defragger returns when its made a big enough block. This is a good time to defrag as we're probably not
{ //doing anything super time-critical at the moment
return(0); //error - couldn't find a big enough space
}
//an exact fit?
if (mem_list[nu_block].size==size) //no new block is required as the fit is perfect
{
mem_list[nu_block].state=type; //locked or float
mem_list[nu_block].size=size; //set to the required size
mem_list[nu_block].uid=unique_id; //an identifier
#ifdef MEMDEBUG
Mem_debug();
#endif //MEMDEBUG
return(&mem_list[nu_block]);
}
// nu_block is the free block to split, forming our locked/float block with a new free block in any remaining space
//if our child is free then is can expand downwards to eat up our chopped space
//this is good because it doesn't create an extra bloc so keeping the block count down
//why?
//imagine you Talloc 1000k, then free it. Now keep allocating 10 bytes less and freeing again
//you end up with thousands of new free mini blocks. this way avoids that as the free child keeps growing downwards
if ((mem_list[nu_block].child != -1) && (mem_list[mem_list[nu_block].child].state==MEM_free)) //our child is free
{
slack=mem_list[nu_block].size-size; //the spare memory is the blocks current size minus the amount we're taking
mem_list[nu_block].state=type; //locked or float
mem_list[nu_block].size=size; //set to the required size
mem_list[nu_block].uid=unique_id; //an identifier
mem_list[mem_list[nu_block].child].ad = mem_list[nu_block].ad+size; //child starts after us
mem_list[mem_list[nu_block].child].size += slack; //childs size increases
return(&mem_list[nu_block]);
}
// otherwise we spawn a new block after us and before our child - our child being a proper block that we cannot change
// we remain a child of our parent
// we spawn a new child and it inherits our current child
//find a NULL slot for a new block
while((mem_list[spawn].state!=MEM_null)&&(spawn!=MAX_mem_blocks))
spawn++;
if (spawn==MAX_mem_blocks) //run out of blocks - stop the program. this is a major blow up and we need to alert the developer
{
Mem_debug(); //Lets get a printout of this
ExitWithReport("ERROR: ran out of mem blocks in Talloc() [file=%s line=%u]",__FILE__,__LINE__);
}
mem_list[spawn].state=MEM_free; //new block is free
mem_list[spawn].uid=UID_memman; //a memman created bloc
mem_list[spawn].size= mem_list[nu_block].size-size; //size of the existing parent free block minus the size of the new space Talloc'ed.
//IOW the remaining memory is given to the new free block
mem_list[spawn].ad = mem_list[nu_block].ad+size; //we start 1 byte after the newly allocated block
mem_list[spawn].parent=nu_block; //the spawned child gets it parent - the newly allocated block
mem_list[spawn].child=mem_list[nu_block].child; //the new child inherits the parents old child (we are its new child "Waaaa")
if (mem_list[spawn].child!=-1) //is the spawn the end block?
mem_list[mem_list[spawn].child].parent= spawn; //the child of the new free-spawn needs to know its new parent
mem_list[nu_block].state=type; //locked or float
mem_list[nu_block].size=size; //set to the required size
mem_list[nu_block].uid=unique_id; //an identifier
mem_list[nu_block].child=spawn; //the new blocks new child is the newly formed free block
total_blocks++; //we've brought a new block into the world. Ahhh!
#ifdef MEMDEBUG
Mem_debug();
#endif //MEMDEBUG
return(&mem_list[nu_block]);
}
//------------------------------------------------------------------------------------
void Free_mem(mem *block) //Tony10Apr96
{
//kill a block of memory - which was presumably floating or locked
//once you've done this the memory may be recycled
block->state=MEM_free;
block->uid=UID_memman; //belongs to the memory manager again
#ifdef MEMDEBUG
Mem_debug();
#endif //MEMDEBUG
}
//------------------------------------------------------------------------------------
void Float_mem(mem *block) //Tony10Apr96
{
//set a block to float
//wont be trashed but will move around in memory
block->state=MEM_float;
#ifdef MEMDEBUG
Mem_debug();
#endif //MEMDEBUG
}
//------------------------------------------------------------------------------------
void Lock_mem(mem *block) //Tony11Apr96
{
//set a block to lock
//wont be moved - don't lock memory for any longer than necessary unless you know the locked memory is at the bottom of the heap
block->state=MEM_locked; //can't move now - this block is now crying out to be floated or free'd again
#ifdef MEMDEBUG
Mem_debug();
#endif //MEMDEBUG
}
//------------------------------------------------------------------------------------
int32 Defrag_mem(uint32 req_size) //Tony10Apr96
{
//moves floating blocks down and/or merges free blocks until a large enough space is found
//or there is nothing left to do and a big enough block cannot be found
//we stop when we find/create a large enough block - this is enough defragging.
int32 cur_block; //block 0 remains the parent block
int32 original_parent,child, end_child;
uint32 j;
uint32 *a;
uint32 *b;
// cur_block=base_mem_block; //the mother of all parents
cur_block = suggestedStart;
do
{
if (mem_list[cur_block].state==MEM_free) //is current block a free block?
{
if (mem_list[cur_block].size>=req_size)
{
return(cur_block); //this block is big enough - return its id
}
if (mem_list[cur_block].child==-1) //the child is the end block - stop if the next block along is the end block
return(-1); //no luck, couldn't find a big enough block
// current free block is too small, but if its child is *also* free then merge the two together
if (mem_list[mem_list[cur_block].child].state==MEM_free)
{
// ok, we nuke the child and inherit its child
child=mem_list[cur_block].child;
mem_list[cur_block].size+= mem_list[child].size; //our size grows by the size of our child
mem_list[cur_block].child = mem_list[child].child; //our new child is our old childs, child
if (mem_list[child].child!=-1) //not if the chld we're nuking is the end child (it has no child)
mem_list[mem_list[child].child].parent=cur_block; //the (nuked) old childs childs parent is now us
mem_list[child].state=MEM_null; //clean up the nuked child, so it can be used again
total_blocks--;
}
// current free block is too small, but if its child is a float then we move the floating memory block down and the free up
// but, parent/child relationships must be such that the memory is all continuous between blocks. ie. a childs memory always
// begins 1 byte after its parent finishes. However, the positions in the memory list may become truly random, but, any particular
// block of locked or floating memory must retain its position within the mem_list - the float stays a float because the handle/pointer has been passed back
// what this means is that when the physical memory of the foat moves down (and the free up) the child becomes the parent and the parent the child
// but, remember, the parent had a parent and the child another child - these swap over too as the parent/child swap takes place - phew.
else if (mem_list[mem_list[cur_block].child].state==MEM_float)
{
child=mem_list[cur_block].child; //our child is currently floating
// memcpy(mem_list[cur_block].ad, mem_list[child].ad, mem_list[child].size); //move the higher float down over the free block
a=(uint32*) mem_list[cur_block].ad;
b=(uint32*) mem_list[child].ad;
for (j=0;j<mem_list[child].size/4;j++)
*(a++)=*(b++);
// both *ad's change
mem_list[child].ad = mem_list[cur_block].ad; //the float is now where the free was
mem_list[cur_block].ad += mem_list[child].size; //and the free goes up by the size of the float (which has come down)
// the status of the mem_list blocks must remain the same, so...
original_parent= mem_list[cur_block].parent; //our child gets this when we become its child and it our parent
mem_list[cur_block].parent=child; //the free's child becomes its parent
mem_list[cur_block].child= mem_list[child].child; //the new child inherits its previous childs child
end_child=mem_list[child].child; //save this - see next line
mem_list[child].child=cur_block; //the floats parent becomes its child
mem_list[child].parent= original_parent;
if (end_child!=-1) //if the child had a child
mem_list[end_child].parent=cur_block; //then its parent is now the new child
if (original_parent==-1) //the base block was the true base parent
base_mem_block=child; //then the child that has moved down becomes the base block as it sits at the lowest possible memory location
else
mem_list[original_parent].child=child; //otherwise the parent of the current free block - that is now the child - gets a new child,
//that child being previously the child of the child of the original parent
}
else //if (mem_list[mem_list[cur_block].child].state==MEM_lock) //the child of current is locked - move to it
cur_block=mem_list[cur_block].child; //move to next one along - either locked or END
}
else
{
cur_block=mem_list[cur_block].child; //move to next one along, the current must be floating, locked, or a NULL slot
}
}
while(cur_block!=-1); //while the block we've just done is not the final block
return(-1); //no luck, couldn't find a big enough block
}
//------------------------------------------------------------------------------------
void Mem_debug(void) //Tony11Apr96
{
//gets called with Talloc, Mem_free, Mem_lock & Mem_float if MEMDEBUG has been #defined
//otherwise can be called at any time anywhere else
int j;
char inf[][20]=
{
{"MEM_null"},
{"MEM_free"},
{"MEM_locked"},
{"MEM_float"}
};
Zdebug("\nbase %d total %d", base_mem_block, total_blocks);
//first in mem list order
for (j=0;j<MAX_mem_blocks;j++)
{
if (mem_list[j].state==MEM_null)
Zdebug("%d- NULL", j);
else
Zdebug("%d- state %s, ad %d, size %d, p %d, c %d, id %d", j,
inf[mem_list[j].state],
mem_list[j].ad, mem_list[j].size, mem_list[j].parent, mem_list[j].child, mem_list[j].uid);
}
//now in child/parent order
j=base_mem_block;
do
{
Zdebug(" %d- state %s, ad %d, size %d, p %d, c %d", j,
inf[mem_list[j].state],
mem_list[j].ad, mem_list[j].size, mem_list[j].parent, mem_list[j].child, mem_list[j].uid);
j=mem_list[j].child;
}
while (j!=-1);
}
//------------------------------------------------------------------------------------
//------------------------------------------------------------------------------------
//------------------------------------------------------------------------------------
mem *Twalloc(uint32 size, uint32 type, uint32 unique_id) //tony12Feb97
{
//the high level Talloc
//can ask the resman to remove old resources to make space - will either do it or halt the system
mem *membloc;
int j;
uint32 free=0;
while( VirtualDefrag(size) )
{
if (!res_man.Help_the_aged_out()) //trash the oldest closed resource
{
Zdebug("Twalloc ran out of memory! %d %d %d\n", size, type, unique_id);
ExitWithReport("Twalloc ran out of memory!");
}
}
membloc = Talloc(size, type, unique_id);
if (membloc == 0)
{
Zdebug("Talloc failed to get memory VirtualDefrag said was there");
ExitWithReport("Talloc failed to get memory VirtualDefrag said was there");
}
j=base_mem_block;
do
{
if (mem_list[j].state==MEM_free)
free+=mem_list[j].size;
j=mem_list[j].child;
}
while (j!=-1);
return(membloc); //return the pointer to the memory
}
#define MAX_WASTAGE 51200 // Maximum allowed wasted memory.
int32 VirtualDefrag( uint32 size ) // Chris - 07 April '97
{
//
// Virutually defrags memory...
//
// Used to determine if there is potentially are large enough free block available is the
// real defragger was allowed to run.
//
// The idea being that Twalloc will call this and help_the_aged_out until we indicate that
// it is possible to obtain a large enough free block. This way the defragger need only
// run once to yield the required block size.
//
// The reason for its current slowness is that the defragger is potentially called several
// times, each time shifting upto 20Megs around, to obtain the required free block.
//
int32 cur_block;
uint32 currentBubbleSize = 0;
cur_block=base_mem_block;
suggestedStart = base_mem_block;
do
{
if (mem_list[cur_block].state == MEM_free)
{
// Add a little intelligence. At the start the oldest resources are at the bottom of the
// tube. However there will be some air at the top. Thus bubbles will be
// created at the bottom and float to the top. If we ignore the top gap
// then a large enough bubble will form lower down the tube. Thus less memory
// will need to be shifted.
if (mem_list[cur_block].child != -1)
currentBubbleSize += mem_list[cur_block].size;
else if (mem_list[cur_block].size > MAX_WASTAGE)
currentBubbleSize += mem_list[cur_block].size;
if (currentBubbleSize >= size)
return 0;
}
else if (mem_list[cur_block].state == MEM_locked)
{
currentBubbleSize = 0;
suggestedStart = mem_list[cur_block].child; // Any free block of the correct size will be above this locked block.
}
cur_block = mem_list[cur_block].child;
}
while(cur_block != -1);
return(1);
}
//------------------------------------------------------------------------------------
//------------------------------------------------------------------------------------
//------------------------------------------------------------------------------------
//------------------------------------------------------------------------------------
//------------------------------------------------------------------------------------