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First post, by superfury

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Would a linked list (entry ptr, next ptr, prev ptr in 8 records, initialized linearly) provide a speedup compared to an array-sort LRU method of sorting and placing increasing numbers in the entries themselves?

The TLB has 8 sorted entries, with 4 way association(so 8x4 sets to sort, one at a time)?

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Older UniPCemu PC/Android/PSP releases

Reply 1 of 4, by superfury

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Just took a look at https://www.quora.com/Why-is-doubly-linked-li … e-GeeksforGeeks .

After understanding the principles of how it works(in a rough sense; it's pretty simple when you think about it), I started coding myself and came up with this(in UniPCemu's paging code algorithm):

https://bitbucket.org/superfury/unipcemu/src/ … ing.c?at=master

The core of the new TLB LRU algorithm is:

typedef struct
{
uint_32 data; //80386 4-way associative TLB results!
uint_32 TAG; //All TAGs used with the respective TLB!
} TLBEntry;

typedef struct
{
TLBEntry *entry; //What entry are we?
byte index; //What index is said entry?
void *prev, *next; //Previous and next pointers!
byte allocated; //Are we allocated?
} TLB_ptr;

typedef struct
{
TLBEntry TLB[4][8]; //All TLB entries to use!
TLB_ptr TLB_listnodes[4][8]; //All nodes for all TLB entries!
TLB_ptr *TLB_freelist_head[4], *TLB_freelist_tail[4]; //Head and tail of the free list!
TLB_ptr *TLB_usedlist_head[4], *TLB_usedlist_tail[4]; //Head and tail of the used list!
} CPU_TLB; //A TLB to use for the CPU!
void PagingTLB_initlists()
{
byte set; //What set?
byte index; //What index?
TLB_ptr *us; //What is the current entry!
for (set = 0; set < 4; ++set) //process all sets!
{
//Allocate a list from the available entry space, with all items in ascending order in a linked list and index!
CPU[activeCPU].Paging_TLB.TLB_freelist_head[set] = CPU[activeCPU].Paging_TLB.TLB_freelist_tail[set] = NULL; //Nothing!
CPU[activeCPU].Paging_TLB.TLB_usedlist_head[set] = CPU[activeCPU].Paging_TLB.TLB_usedlist_tail[set] = NULL; //Nothing!
for (index = 7; ((index&0xFF)!=0xFF); --index) //process all indexes!
{
CPU[activeCPU].Paging_TLB.TLB_listnodes[set][index].entry = &CPU[activeCPU].Paging_TLB.TLB[set][index]; //What entry(constant value)!
CPU[activeCPU].Paging_TLB.TLB_listnodes[set][index].index = index; //What index are we(for lookups)?
CPU[activeCPU].Paging_TLB.TLB_listnodes[set][index].allocated = 0; //We're in the free list!
us = &CPU[activeCPU].Paging_TLB.TLB_listnodes[set][index]; //What entry are we?
us->prev = NULL; //We start out as the head for the added items here, so never anything before us!
us->next = NULL; //We start out as the head, so next is automatically filled!
if (CPU[activeCPU].Paging_TLB.TLB_freelist_head[set]) //Head already set?
{
CPU[activeCPU].Paging_TLB.TLB_freelist_head[set]->prev = us; //We're the previous for the current head!
us->next = CPU[activeCPU].Paging_TLB.TLB_freelist_head[set]; //Our next is the head!
}
CPU[activeCPU].Paging_TLB.TLB_freelist_head[set] = us; //We're the new head!
if (CPU[activeCPU].Paging_TLB.TLB_freelist_tail[set] == NULL) //No tail yet?
{
CPU[activeCPU].Paging_TLB.TLB_freelist_tail[set] = CPU[activeCPU].Paging_TLB.TLB_freelist_head[set]; //Tail=Head when starting out!
}
}
}
}

//Move a TLB entry index from an old list to a new list!
void Paging_moveListItem(TLB_ptr *listitem, TLB_ptr **newlist_head, TLB_ptr **newlist_tail, TLB_ptr **oldlist_head, TLB_ptr **oldlist_tail)
{
//First, remove us from the old head list!
if (listitem->prev) //Do we have anything before us?
{
((TLB_ptr *)listitem->prev)->next = listitem->next; //Remove us from the previous item of the list!
}
else //We're the head, so remove us from the list!
{
*oldlist_head = listitem->next; //Remove us from the head of the list and assign the new head!
}

if (listitem->next) //Did we have a next item?
{
((TLB_ptr *)listitem->next)->prev = listitem->prev; //Remove us from the next item of the list!
}
else //We're the tail?
{
*oldlist_tail = listitem->prev; //Remove us from the tail of the list and assign the new tail!
}

listitem->next = NULL; //We don't have a next!
listitem->prev = NULL; //We don't have a previous!

/* Now, we're removed from the old list and a newly unmapped item! */

//Now, insert us into the start of the new list!
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	if (*newlist_head) //Anything in the new list already?
{
(*newlist_head)->prev = listitem; //We're at the start of the new list, so point the head to us, us to the head and make us the new head!
listitem->next = *newlist_head; //Our next is the old head!
*newlist_head = listitem; //We're the new head!
}
else //We're the new list?
{
*newlist_head = listitem; //We're the new head!
*newlist_tail = listitem; //We're the new tail!
}
}

TLB_ptr *allocTLB(sbyte set) //Allocate a TLB entry!
{
TLB_ptr *result;
if (CPU[activeCPU].Paging_TLB.TLB_freelist_head) //Anything available?
{
result = CPU[activeCPU].Paging_TLB.TLB_freelist_head[set]; //What item are we allocating, take it from the free list!
//Now take the item from the pool and move it to the used list!
CPU[activeCPU].Paging_TLB.TLB_freelist_head[set]->allocated = 1; //We're allocated now!
Paging_moveListItem(CPU[activeCPU].Paging_TLB.TLB_freelist_head[set], //What item to take!
&CPU[activeCPU].Paging_TLB.TLB_usedlist_head[set], //destination head
&CPU[activeCPU].Paging_TLB.TLB_usedlist_tail[set], //destination tail
&CPU[activeCPU].Paging_TLB.TLB_freelist_head[set], //source head
&CPU[activeCPU].Paging_TLB.TLB_freelist_tail[set]); //source tail
return result; //Give the result!
}
return NULL; //Nothing to allocate!
}

void freeTLB(sbyte set, byte TLB_index) //Make an entry available again!
{
TLB_ptr *listitem;
listitem = &CPU[activeCPU].Paging_TLB.TLB_listnodes[set][TLB_index]; //Our entry!
if (listitem->allocated) //Are we allocated at all?
{
listitem->allocated = 0; //Mark us as freed!
Paging_moveListItem(listitem, //What item to take!
&CPU[activeCPU].Paging_TLB.TLB_freelist_head[set], //destination head
&CPU[activeCPU].Paging_TLB.TLB_freelist_tail[set], //destination tail
&CPU[activeCPU].Paging_TLB.TLB_usedlist_head[set], //source head
&CPU[activeCPU].Paging_TLB.TLB_usedlist_tail[set]); //source tail
}
}

void Paging_setNewestTLB(sbyte set, byte TLB_index) //Tick an TLB entry for making it the most recently used!
{
TLB_ptr *listitem;
listitem = &CPU[activeCPU].Paging_TLB.TLB_listnodes[set][TLB_index]; //Our entry!
if (listitem->allocated) //Are we allocated at all?
{
Paging_moveListItem(listitem,
&CPU[activeCPU].Paging_TLB.TLB_usedlist_head[set],
&CPU[activeCPU].Paging_TLB.TLB_usedlist_tail[set],
&CPU[activeCPU].Paging_TLB.TLB_usedlist_head[set],
&CPU[activeCPU].Paging_TLB.TLB_usedlist_tail[set]); //Move us to the start of the TLB used list to mark us as the most recently accessed!
}
else //We're not allocated, but marked as newest? Allocate us!
{
listitem = &CPU[activeCPU].Paging_TLB.TLB_listnodes[set][TLB_index]; //Our entry!
//Now take the item from the pool and move it to the used list!
listitem->allocated = 1; //We're allocated now!
Paging_moveListItem(listitem, //What item to take!
&CPU[activeCPU].Paging_TLB.TLB_usedlist_head[set], //destination head
&CPU[activeCPU].Paging_TLB.TLB_usedlist_tail[set], //destination tail
&CPU[activeCPU].Paging_TLB.TLB_freelist_head[set], //source head
&CPU[activeCPU].Paging_TLB.TLB_freelist_tail[set]); //source tail
}
}

byte Paging_oldestTLB(sbyte set) //Find a TLB to be used/overwritten!
{
TLB_ptr *entry;
if (CPU[activeCPU].Paging_TLB.TLB_freelist_head[set]) //Anything not allocated yet?
{
if (entry = allocTLB(set)) //Allocated from the free list?
{
return entry->index; //Give the index of the resulting entry that's been allocated!
}
}
else //Allocate from the tail(LRU), since everything is allocated!
{
if (CPU[activeCPU].Paging_TLB.TLB_usedlist_tail[set]) //Gotten a tail? We're used, so take the LRU!
{
entry = CPU[activeCPU].Paging_TLB.TLB_usedlist_tail[set]; //What entry to take: the LRU!
Paging_setNewestTLB(set, entry->index); //This is the newest TLB now!
return entry->index; //What index is the LRU!
}
}
return 7;
}

Then the write/read/init TLB functions use it like this(barely adjusted):

void Paging_writeTLB(sbyte TLB_set, uint_32 logicaladdress, byte W, byte U, byte D, uint_32 result)
{
byte effectiveentry;
uint_32 TAG,TAGMASKED;
if (TLB_set < 0) TLB_set = Paging_TLBSet(logicaladdress); //Auto set?
TAG = Paging_generateTAG(logicaladdress, W, U, D); //Generate a TAG!
byte entry;
TAGMASKED = (TAG&0xFFFFF001); //Masked tag for fast lookup! Match P/U/W/address only! Thus dirty updates the existing entry, while other bit changing create a new entry!
effectiveentry = 0;
entry = 8; //Init for entry search not found!
do
{
if (CPU[activeCPU].Paging_TLB.TLB_listnodes[TLB_set][effectiveentry].allocated) //Allocated entry?
{
if ((CPU[activeCPU].Paging_TLB.TLB[TLB_set][effectiveentry].TAG & 0xFFFFF001) == TAGMASKED) //Match for our own entry?
{
entry = effectiveentry; //Reuse our own entry!
break; //Stop searching: reuse the effective entry!
}
}
} while (++effectiveentry < 8); //Check all entries!
if (entry == 8) //Not found? Take the LRU!
{
entry = Paging_oldestTLB(TLB_set); //Get the oldest/unused TLB!
}
else //We're the newest TLB now!
{
Paging_setNewestTLB(TLB_set, entry); //We're the newest TLB now!
}
CPU[activeCPU].Paging_TLB.TLB[TLB_set][entry].data = result; //The result for the lookup!
CPU[activeCPU].Paging_TLB.TLB[TLB_set][entry].TAG = TAG; //The TAG to find it by!
}

//RWDirtyMask: mask for ignoring set bits in the tag, use them otherwise!
byte Paging_readTLB(sbyte TLB_set, uint_32 logicaladdress, byte W, byte U, byte D, uint_32 WDMask, uint_32 *result, byte updateAges)
{
INLINEREGISTER uint_32 TAG, TAGMask;
INLINEREGISTER byte entry = 0;
INLINEREGISTER TLBEntry *curentry;
if (TLB_set < 0) TLB_set = Paging_TLBSet(logicaladdress); //Auto set?
TAG = Paging_generateTAG(logicaladdress,W,U,D); //Generate a TAG!
TAGMask = ~WDMask; //Store for fast usage to mask the tag bits unused off!
if (likely(WDMask)) //Used?
{
TAG &= TAGMask; //Ignoring these bits, so mask them off when comparing!
}
curentry = &CPU[activeCPU].Paging_TLB.TLB[TLB_set][0]; //What TLB entry to apply?
do //Check all entries!
{
if (likely(((curentry->TAG&TAGMask)==TAG) && (CPU[activeCPU].Paging_TLB.TLB_listnodes[TLB_set][entry].allocated))) //Found?
{
*result = curentry->data; //Give the stored data!
Paging_setNewestTLB(TLB_set, entry); //Set us as the newest TLB!
return 1; //Found!
}
++curentry; //Next entry!
} while (likely(++entry<8));
return 0; //Not found!
}

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void Paging_Invalidate(uint_32 logicaladdress) //Invalidate a single address!
{
INLINEREGISTER byte TLB_set;
INLINEREGISTER byte entry;
for (TLB_set = 0; TLB_set < 4; ++TLB_set) //Process all possible sets!
{
for (entry = 0; entry < 8; ++entry) //Check all entries!
{
if (Paging_matchTLBaddress(logicaladdress, CPU[activeCPU].Paging_TLB.TLB[TLB_set][entry].TAG)) //Matched?
{
CPU[activeCPU].Paging_TLB.TLB[TLB_set][entry].TAG = 0; //Clear the entry to unused!
freeTLB(TLB_set, entry); //Free this entry from the TLB!
}
}
}
}

void Paging_clearTLB()
{
memset(&CPU[activeCPU].Paging_TLB,0,sizeof(CPU[activeCPU].Paging_TLB)); //Reset fully and clear the TLB!
PagingTLB_initlists(); //Initialize the TLB lists to become empty!
}

I still see Windows NT booting like always, so it can't be that wrong? What are your opinions?

UniPCemu Git repository
UniPCemu for Android, Windows and PSP on itch.io
Older UniPCemu PC/Android/PSP releases

Reply 2 of 4, by superfury

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Hmmmm.... Interesting.... When running Simcity 2000 with paging deliberately enabled(with "set dos4gvm=maxmem#4096 virtualsize#32768 swapname#d:\swapfile.swp"), I see it crashing in protected mode over and over again on a FFFFh opcode? Interesting, since it runs fine in normal mode(without paging afaik).

UniPCemu Git repository
UniPCemu for Android, Windows and PSP on itch.io
Older UniPCemu PC/Android/PSP releases

Reply 3 of 4, by superfury

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Now trying to run Prime95 under MS-DOS to check for bugs. So far up to DMA controllers pass(Cache memory hangs it seems).

UniPCemu Git repository
UniPCemu for Android, Windows and PSP on itch.io
Older UniPCemu PC/Android/PSP releases

Reply 4 of 4, by superfury

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Managed to optimize it a bit by inlining the code and ignoring moving entries from the head to the head of the same queue(so in effect nothing happens, just wasted instructions).

TLB entry allocation/free/LRU/MRU handling:

OPTINLINE void PagingTLB_initlists()
{
byte set; //What set?
byte index; //What index?
TLB_ptr *us; //What is the current entry!
for (set = 0; set < 4; ++set) //process all sets!
{
//Allocate a list-to-entry-mapping from the available entry space, with all items in ascending order in a linked list and index!
for (index = 0; (index<8); ++index) //process all indexes!
{
CPU[activeCPU].Paging_TLB.TLB_listnodes[set][index].entry = &CPU[activeCPU].Paging_TLB.TLB[set][index]; //What entry(constant value)!
CPU[activeCPU].Paging_TLB.TLB_listnodes[set][index].index = index; //What index are we(for lookups)?
}
}
}

OPTINLINE void PagingTLB_clearlists()
{
byte set; //What set?
byte index; //What index?
TLB_ptr *us; //What is the current entry!
for (set = 0; set < 4; ++set) //process all sets!
{
//Allocate a list from the available entry space, with all items in ascending order in a linked list and index!
CPU[activeCPU].Paging_TLB.TLB_freelist_head[set] = CPU[activeCPU].Paging_TLB.TLB_freelist_tail[set] = NULL; //Nothing!
CPU[activeCPU].Paging_TLB.TLB_usedlist_head[set] = CPU[activeCPU].Paging_TLB.TLB_usedlist_tail[set] = NULL; //Nothing!
for (index = 7; ((index&0xFF)!=0xFF); --index) //process all indexes!
{
CPU[activeCPU].Paging_TLB.TLB_listnodes[set][index].allocated = 0; //We're in the free list!
us = &CPU[activeCPU].Paging_TLB.TLB_listnodes[set][index]; //What entry are we?
us->prev = NULL; //We start out as the head for the added items here, so never anything before us!
us->next = NULL; //We start out as the head, so next is automatically filled!
if (likely(CPU[activeCPU].Paging_TLB.TLB_freelist_head[set])) //Head already set?
{
CPU[activeCPU].Paging_TLB.TLB_freelist_head[set]->prev = us; //We're the previous for the current head!
us->next = CPU[activeCPU].Paging_TLB.TLB_freelist_head[set]; //Our next is the head!
}
CPU[activeCPU].Paging_TLB.TLB_freelist_head[set] = us; //We're the new head!
if (unlikely(CPU[activeCPU].Paging_TLB.TLB_freelist_tail[set] == NULL)) //No tail yet?
{
CPU[activeCPU].Paging_TLB.TLB_freelist_tail[set] = CPU[activeCPU].Paging_TLB.TLB_freelist_head[set]; //Tail=Head when starting out!
}
}
}
}

//Move a TLB entry index from an old list to a new list!
OPTINLINE void Paging_moveListItem(TLB_ptr *listitem, TLB_ptr **newlist_head, TLB_ptr **newlist_tail, TLB_ptr **oldlist_head, TLB_ptr **oldlist_tail)
{
if (likely(*newlist_head == listitem)) return; //Don't do anything when it's already at the correct spot!

//First, remove us from the old head list!
if (listitem->prev) //Do we have anything before us?
{
((TLB_ptr *)listitem->prev)->next = listitem->next; //Remove us from the previous item of the list!
}
else //We're the head, so remove us from the list!
{
*oldlist_head = listitem->next; //Remove us from the head of the list and assign the new head!
}
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if (listitem->next) //Did we have a next item?
{
((TLB_ptr *)listitem->next)->prev = listitem->prev; //Remove us from the next item of the list!
}
else //We're the tail?
{
*oldlist_tail = listitem->prev; //Remove us from the tail of the list and assign the new tail!
}

listitem->next = NULL; //We don't have a next!
listitem->prev = NULL; //We don't have a previous!

/* Now, we're removed from the old list and a newly unmapped item! */

//Now, insert us into the start of the new list!
if (*newlist_head) //Anything in the new list already?
{
(*newlist_head)->prev = listitem; //We're at the start of the new list, so point the head to us, us to the head and make us the new head!
listitem->next = *newlist_head; //Our next is the old head!
*newlist_head = listitem; //We're the new head!
}
else //We're the new list?
{
*newlist_head = listitem; //We're the new head!
*newlist_tail = listitem; //We're the new tail!
}
}

OPTINLINE TLB_ptr *allocTLB(sbyte set) //Allocate a TLB entry!
{
TLB_ptr *result;
if (CPU[activeCPU].Paging_TLB.TLB_freelist_head) //Anything available?
{
result = CPU[activeCPU].Paging_TLB.TLB_freelist_head[set]; //What item are we allocating, take it from the free list!
//Now take the item from the pool and move it to the used list!
CPU[activeCPU].Paging_TLB.TLB_freelist_head[set]->allocated = 1; //We're allocated now!
Paging_moveListItem(CPU[activeCPU].Paging_TLB.TLB_freelist_head[set], //What item to take!
&CPU[activeCPU].Paging_TLB.TLB_usedlist_head[set], //destination head
&CPU[activeCPU].Paging_TLB.TLB_usedlist_tail[set], //destination tail
&CPU[activeCPU].Paging_TLB.TLB_freelist_head[set], //source head
&CPU[activeCPU].Paging_TLB.TLB_freelist_tail[set]); //source tail
return result; //Give the result!
}
return NULL; //Nothing to allocate!
}

OPTINLINE void freeTLB(sbyte set, byte TLB_index) //Make an entry available again!
{
TLB_ptr *listitem;
listitem = &CPU[activeCPU].Paging_TLB.TLB_listnodes[set][TLB_index]; //Our entry!
if (listitem->allocated) //Are we allocated at all?
{
listitem->allocated = 0; //Mark us as freed!
Paging_moveListItem(listitem, //What item to take!
&CPU[activeCPU].Paging_TLB.TLB_freelist_head[set], //destination head
&CPU[activeCPU].Paging_TLB.TLB_freelist_tail[set], //destination tail
&CPU[activeCPU].Paging_TLB.TLB_usedlist_head[set], //source head
&CPU[activeCPU].Paging_TLB.TLB_usedlist_tail[set]); //source tail
}
}

OPTINLINE void Paging_setNewestTLB(sbyte set, byte TLB_index) //Tick an TLB entry for making it the most recently used!
{
TLB_ptr *listitem;
listitem = &CPU[activeCPU].Paging_TLB.TLB_listnodes[set][TLB_index]; //Our entry!
if (listitem->allocated) //Are we allocated at all?
{
Paging_moveListItem(listitem,
&CPU[activeCPU].Paging_TLB.TLB_usedlist_head[set],
&CPU[activeCPU].Paging_TLB.TLB_usedlist_tail[set],
&CPU[activeCPU].Paging_TLB.TLB_usedlist_head[set],
&CPU[activeCPU].Paging_TLB.TLB_usedlist_tail[set]); //Move us to the start of the TLB used list to mark us as the most recently accessed!
}
else //We're not allocated, but marked as newest? Allocate us!
{
//Now take the item from the pool and move it to the used list!
listitem->allocated = 1; //We're allocated now!
Paging_moveListItem(listitem, //What item to take!
&CPU[activeCPU].Paging_TLB.TLB_usedlist_head[set], //destination head
&CPU[activeCPU].Paging_TLB.TLB_usedlist_tail[set], //destination tail
&CPU[activeCPU].Paging_TLB.TLB_freelist_head[set], //source head
&CPU[activeCPU].Paging_TLB.TLB_freelist_tail[set]); //source tail
}
}

OPTINLINE byte Paging_oldestTLB(sbyte set) //Find a TLB to be used/overwritten!
{
TLB_ptr *entry;
if (CPU[activeCPU].Paging_TLB.TLB_freelist_head[set]) //Anything not allocated yet?
{
if (entry = allocTLB(set)) //Allocated from the free list?
{
return entry->index; //Give the index of the resulting entry that's been allocated!
}
}
else //Allocate from the tail(LRU), since everything is allocated!
{
if (CPU[activeCPU].Paging_TLB.TLB_usedlist_tail[set]) //Gotten a tail? We're used, so take the LRU!
{
entry = CPU[activeCPU].Paging_TLB.TLB_usedlist_tail[set]; //What entry to take: the LRU!
Paging_setNewestTLB(set, entry->index); //This is the newest TLB now!
return entry->index; //What index is the LRU!
}
}
return 7; //Safety: return the final entry! Shouldn't happen under normal circumstances.
}

TLB reads/writes/initialization/clearing:

void Paging_writeTLB(sbyte TLB_set, uint_32 logicaladdress, byte W, byte U, byte D, uint_32 result)
{
byte effectiveentry;
uint_32 TAG,TAGMASKED;
if (TLB_set < 0) TLB_set = Paging_TLBSet(logicaladdress); //Auto set?
TAG = Paging_generateTAG(logicaladdress, W, U, D); //Generate a TAG!
byte entry;
TAGMASKED = (TAG&0xFFFFF001); //Masked tag for fast lookup! Match P/U/W/address only! Thus dirty updates the existing entry, while other bit changing create a new entry!
effectiveentry = 0;
entry = 8; //Init for entry search not found!
do
{
if (CPU[activeCPU].Paging_TLB.TLB_listnodes[TLB_set][effectiveentry].allocated) //Allocated entry?
{
if ((CPU[activeCPU].Paging_TLB.TLB[TLB_set][effectiveentry].TAG & 0xFFFFF001) == TAGMASKED) //Match for our own entry?
{
entry = effectiveentry; //Reuse our own entry!
break; //Stop searching: reuse the effective entry!
}
}
} while (++effectiveentry < 8); //Check all entries!
if (entry == 8) //Not found? Take the LRU!
{
entry = Paging_oldestTLB(TLB_set); //Get the oldest/unused TLB!
}
else //We're the newest TLB now!
{
Paging_setNewestTLB(TLB_set, entry); //We're the newest TLB now!
}
CPU[activeCPU].Paging_TLB.TLB[TLB_set][entry].data = result; //The result for the lookup!
CPU[activeCPU].Paging_TLB.TLB[TLB_set][entry].TAG = TAG; //The TAG to find it by!
}

//RWDirtyMask: mask for ignoring set bits in the tag, use them otherwise!
byte Paging_readTLB(sbyte TLB_set, uint_32 logicaladdress, byte W, byte U, byte D, uint_32 WDMask, uint_32 *result, byte updateAges)
{
INLINEREGISTER uint_32 TAG, TAGMask;
INLINEREGISTER byte entry = 0;
INLINEREGISTER TLBEntry *curentry;
if (TLB_set < 0) TLB_set = Paging_TLBSet(logicaladdress); //Auto set?
TAG = Paging_generateTAG(logicaladdress,W,U,D); //Generate a TAG!
TAGMask = ~WDMask; //Store for fast usage to mask the tag bits unused off!
if (likely(WDMask)) //Used?
{
TAG &= TAGMask; //Ignoring these bits, so mask them off when comparing!
}
curentry = &CPU[activeCPU].Paging_TLB.TLB[TLB_set][0]; //What TLB entry to apply?
do //Check all entries!
{
if (likely(((curentry->TAG&TAGMask)==TAG) && (CPU[activeCPU].Paging_TLB.TLB_listnodes[TLB_set][entry].allocated))) //Found?
{
*result = curentry->data; //Give the stored data!
Paging_setNewestTLB(TLB_set, entry); //Set us as the newest TLB!
return 1; //Found!
}
++curentry; //Next entry!
} while (likely(++entry<8));
return 0; //Not found!
}

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void Paging_Invalidate(uint_32 logicaladdress) //Invalidate a single address!
{
INLINEREGISTER byte TLB_set;
INLINEREGISTER byte entry;
for (TLB_set = 0; TLB_set < 4; ++TLB_set) //Process all possible sets!
{
for (entry = 0; entry < 8; ++entry) //Check all entries!
{
if (Paging_matchTLBaddress(logicaladdress, CPU[activeCPU].Paging_TLB.TLB[TLB_set][entry].TAG) && (CPU[activeCPU].Paging_TLB.TLB_listnodes[TLB_set][entry].allocated)) //Matched?
{
CPU[activeCPU].Paging_TLB.TLB[TLB_set][entry].TAG = 0; //Clear the entry to unused!
freeTLB(TLB_set, entry); //Free this entry from the TLB!
}
}
}
}

void Paging_clearTLB()
{
memset(&CPU[activeCPU].Paging_TLB,0,sizeof(CPU[activeCPU].Paging_TLB)); //Reset fully and clear the TLB!
PagingTLB_clearlists(); //Initialize the TLB lists to become empty!
}

void Paging_initTLB()
{
PagingTLB_initlists(); //Initialize the TLB lists to become empty!
Paging_clearTLB(); //Clear the TLB! This also calls clearlists, initializing the linked lists!
}

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