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/* cache.c - cache module routines */
/* SimpleScalar(TM) Tool Suite
* Copyright (C) 1994-2003 by Todd M. Austin, Ph.D. and SimpleScalar, LLC.
* All Rights Reserved.
*
* THIS IS A LEGAL DOCUMENT, BY USING SIMPLESCALAR,
* YOU ARE AGREEING TO THESE TERMS AND CONDITIONS.
*
* No portion of this work may be used by any commercial entity, or for any
* commercial purpose, without the prior, written permission of SimpleScalar,
* LLC (info@simplescalar.com). Nonprofit and noncommercial use is permitted
* as described below.
*
* 1. SimpleScalar is provided AS IS, with no warranty of any kind, express
* or implied. The user of the program accepts full responsibility for the
* application of the program and the use of any results.
*
* 2. Nonprofit and noncommercial use is encouraged. SimpleScalar may be
* downloaded, compiled, executed, copied, and modified solely for nonprofit,
* educational, noncommercial research, and noncommercial scholarship
* purposes provided that this notice in its entirety accompanies all copies.
* Copies of the modified software can be delivered to persons who use it
* solely for nonprofit, educational, noncommercial research, and
* noncommercial scholarship purposes provided that this notice in its
* entirety accompanies all copies.
*
* 3. ALL COMMERCIAL USE, AND ALL USE BY FOR PROFIT ENTITIES, IS EXPRESSLY
* PROHIBITED WITHOUT A LICENSE FROM SIMPLESCALAR, LLC (info@simplescalar.com).
*
* 4. No nonprofit user may place any restrictions on the use of this software,
* including as modified by the user, by any other authorized user.
*
* 5. Noncommercial and nonprofit users may distribute copies of SimpleScalar
* in compiled or executable form as set forth in Section 2, provided that
* either: (A) it is accompanied by the corresponding machine-readable source
* code, or (B) it is accompanied by a written offer, with no time limit, to
* give anyone a machine-readable copy of the corresponding source code in
* return for reimbursement of the cost of distribution. This written offer
* must permit verbatim duplication by anyone, or (C) it is distributed by
* someone who received only the executable form, and is accompanied by a
* copy of the written offer of source code.
*
* 6. SimpleScalar was developed by Todd M. Austin, Ph.D. The tool suite is
* currently maintained by SimpleScalar LLC (info@simplescalar.com). US Mail:
* 2395 Timbercrest Court, Ann Arbor, MI 48105.
*
* Copyright (C) 1994-2003 by Todd M. Austin, Ph.D. and SimpleScalar, LLC.
*/
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include "host.h"
#include "misc.h"
#include "machine.h"
#include "cache.h"
/* cache access macros */
#define CACHE_TAG(cp, addr) ((addr) >> (cp)->tag_shift)
#define CACHE_SET(cp, addr) (((addr) >> (cp)->set_shift) & (cp)->set_mask)
#define CACHE_BLK(cp, addr) ((addr) & (cp)->blk_mask)
#define CACHE_TAGSET(cp, addr) ((addr) & (cp)->tagset_mask)
/* extract/reconstruct a block address */
#define CACHE_BADDR(cp, addr) ((addr) & ~(cp)->blk_mask)
#define CACHE_MK_BADDR(cp, tag, set) \
(((tag) << (cp)->tag_shift)|((set) << (cp)->set_shift))
/* index an array of cache blocks, non-trivial due to variable length blocks */
#define CACHE_BINDEX(cp, blks, i) \
((struct cache_blk_t *)(((char *)(blks)) + \
(i)*(sizeof(struct cache_blk_t) + \
((cp)->balloc \
? (cp)->bsize*sizeof(byte_t) : 0))))
/* cache data block accessor, type parameterized */
#define __CACHE_ACCESS(type, data, bofs) \
(*((type *)(((char *)data) + (bofs))))
/* cache data block accessors, by type */
#define CACHE_DOUBLE(data, bofs) __CACHE_ACCESS(double, data, bofs)
#define CACHE_FLOAT(data, bofs) __CACHE_ACCESS(float, data, bofs)
#define CACHE_WORD(data, bofs) __CACHE_ACCESS(unsigned int, data, bofs)
#define CACHE_HALF(data, bofs) __CACHE_ACCESS(unsigned short, data, bofs)
#define CACHE_BYTE(data, bofs) __CACHE_ACCESS(unsigned char, data, bofs)
/* cache block hashing macros, this macro is used to index into a cache
set hash table (to find the correct block on N in an N-way cache), the
cache set index function is CACHE_SET, defined above */
#define CACHE_HASH(cp, key) \
(((key >> 24) ^ (key >> 16) ^ (key >> 8) ^ key) & ((cp)->hsize-1))
/* copy data out of a cache block to buffer indicated by argument pointer p */
#define CACHE_BCOPY(cmd, blk, bofs, p, nbytes) \
if (cmd == Read) \
{ \
switch (nbytes) { \
case 1: \
*((byte_t *)p) = CACHE_BYTE(&blk->data[0], bofs); break; \
case 2: \
*((half_t *)p) = CACHE_HALF(&blk->data[0], bofs); break; \
case 4: \
*((word_t *)p) = CACHE_WORD(&blk->data[0], bofs); break; \
default: \
{ /* >= 8, power of two, fits in block */ \
int words = nbytes >> 2; \
while (words-- > 0) \
{ \
*((word_t *)p) = CACHE_WORD(&blk->data[0], bofs); \
p += 4; bofs += 4; \
}\
}\
}\
}\
else /* cmd == Write */ \
{ \
switch (nbytes) { \
case 1: \
CACHE_BYTE(&blk->data[0], bofs) = *((byte_t *)p); break; \
case 2: \
CACHE_HALF(&blk->data[0], bofs) = *((half_t *)p); break; \
case 4: \
CACHE_WORD(&blk->data[0], bofs) = *((word_t *)p); break; \
default: \
{ /* >= 8, power of two, fits in block */ \
int words = nbytes >> 2; \
while (words-- > 0) \
{ \
CACHE_WORD(&blk->data[0], bofs) = *((word_t *)p); \
p += 4; bofs += 4; \
}\
}\
}\
}
/* bound sqword_t/dfloat_t to positive int */
#define BOUND_POS(N) ((int)(MIN(MAX(0, (N)), 2147483647)))
/* unlink BLK from the hash table bucket chain in SET */
static void
unlink_htab_ent(struct cache_t *cp, /* cache to update */
struct cache_set_t *set, /* set containing bkt chain */
struct cache_blk_t *blk) /* block to unlink */
{
struct cache_blk_t *prev, *ent;
int index = CACHE_HASH(cp, blk->tag);
/* locate the block in the hash table bucket chain */
for (prev=NULL,ent=set->hash[index];
ent;
prev=ent,ent=ent->hash_next)
{
if (ent == blk)
break;
}
assert(ent);
/* unlink the block from the hash table bucket chain */
if (!prev)
{
/* head of hash bucket list */
set->hash[index] = ent->hash_next;
}
else
{
/* middle or end of hash bucket list */
prev->hash_next = ent->hash_next;
}
ent->hash_next = NULL;
}
/* insert BLK onto the head of the hash table bucket chain in SET */
static void
link_htab_ent(struct cache_t *cp, /* cache to update */
struct cache_set_t *set, /* set containing bkt chain */
struct cache_blk_t *blk) /* block to insert */
{
int index = CACHE_HASH(cp, blk->tag);
/* insert block onto the head of the bucket chain */
blk->hash_next = set->hash[index];
set->hash[index] = blk;
}
/* where to insert a block onto the ordered way chain */
enum list_loc_t { Head, Tail };
/* insert BLK into the order way chain in SET at location WHERE */
static void
update_way_list(struct cache_set_t *set, /* set contained way chain */
struct cache_blk_t *blk, /* block to insert */
enum list_loc_t where) /* insert location */
{
/* unlink entry from the way list */
if (!blk->way_prev && !blk->way_next)
{
/* only one entry in list (direct-mapped), no action */
assert(set->way_head == blk && set->way_tail == blk);
/* Head/Tail order already */
return;
}
/* else, more than one element in the list */
else if (!blk->way_prev)
{
assert(set->way_head == blk && set->way_tail != blk);
if (where == Head)
{
/* already there */
return;
}
/* else, move to tail */
set->way_head = blk->way_next;
blk->way_next->way_prev = NULL;
}
else if (!blk->way_next)
{
/* end of list (and not front of list) */
assert(set->way_head != blk && set->way_tail == blk);
if (where == Tail)
{
/* already there */
return;
}
set->way_tail = blk->way_prev;
blk->way_prev->way_next = NULL;
}
else
{
/* middle of list (and not front or end of list) */
assert(set->way_head != blk && set->way_tail != blk);
blk->way_prev->way_next = blk->way_next;
blk->way_next->way_prev = blk->way_prev;
}
/* link BLK back into the list */
if (where == Head)
{
/* link to the head of the way list */
blk->way_next = set->way_head;
blk->way_prev = NULL;
set->way_head->way_prev = blk;
set->way_head = blk;
}
else if (where == Tail)
{
/* link to the tail of the way list */
blk->way_prev = set->way_tail;
blk->way_next = NULL;
set->way_tail->way_next = blk;
set->way_tail = blk;
}
else
panic("bogus WHERE designator");
}
/* create and initialize a general cache structure */
struct cache_t * /* pointer to cache created */
cache_create(char *name, /* name of the cache */
int nsets, /* total number of sets in cache */
int bsize, /* block (line) size of cache */
int balloc, /* allocate data space for blocks? */
int usize, /* size of user data to alloc w/blks */
int assoc, /* associativity of cache */
enum cache_policy policy, /* replacement policy w/in sets */
/* block access function, see description w/in struct cache def */
unsigned int (*blk_access_fn)(enum mem_cmd cmd,
md_addr_t baddr, int bsize,
struct cache_blk_t *blk,
tick_t now),
unsigned int hit_latency) /* latency in cycles for a hit */
{
struct cache_t *cp;
struct cache_blk_t *blk;
int i, j, bindex;
/* check all cache parameters */
if (nsets <= 0)
fatal("cache size (in sets) `%d' must be non-zero", nsets);
if ((nsets & (nsets-1)) != 0)
fatal("cache size (in sets) `%d' is not a power of two", nsets);
/* blocks must be at least one datum large, i.e., 8 bytes for SS */
if (bsize < 8)
fatal("cache block size (in bytes) `%d' must be 8 or greater", bsize);
if ((bsize & (bsize-1)) != 0)
fatal("cache block size (in bytes) `%d' must be a power of two", bsize);
if (usize < 0)
fatal("user data size (in bytes) `%d' must be a positive value", usize);
if (assoc <= 0)
fatal("cache associativity `%d' must be non-zero and positive", assoc);
if ((assoc & (assoc-1)) != 0)
fatal("cache associativity `%d' must be a power of two", assoc);
if (!blk_access_fn)
fatal("must specify miss/replacement functions");
/* allocate the cache structure */
cp = (struct cache_t *)
calloc(1, sizeof(struct cache_t) + (nsets-1)*sizeof(struct cache_set_t));
if (!cp)
fatal("out of virtual memory");
/* initialize user parameters */
cp->name = mystrdup(name);
cp->nsets = nsets;
cp->bsize = bsize;
cp->balloc = balloc;
cp->usize = usize;
cp->assoc = assoc;
cp->policy = policy;
cp->hit_latency = hit_latency;
/* miss/replacement functions */
cp->blk_access_fn = blk_access_fn;
/* compute derived parameters */
cp->hsize = CACHE_HIGHLY_ASSOC(cp) ? (assoc >> 2) : 0;
cp->blk_mask = bsize-1;
cp->set_shift = log_base2(bsize);
cp->set_mask = nsets-1;
cp->tag_shift = cp->set_shift + log_base2(nsets);
cp->tag_mask = (1 << (32 - cp->tag_shift))-1;
cp->tagset_mask = ~cp->blk_mask;
cp->bus_free = 0;
/* print derived parameters during debug */
debug("%s: cp->hsize = %d", cp->name, cp->hsize);
debug("%s: cp->blk_mask = 0x%08x", cp->name, cp->blk_mask);
debug("%s: cp->set_shift = %d", cp->name, cp->set_shift);
debug("%s: cp->set_mask = 0x%08x", cp->name, cp->set_mask);
debug("%s: cp->tag_shift = %d", cp->name, cp->tag_shift);
debug("%s: cp->tag_mask = 0x%08x", cp->name, cp->tag_mask);
/* initialize cache stats */
cp->hits = 0;
cp->misses = 0;
cp->replacements = 0;
cp->writebacks = 0;
cp->invalidations = 0;
/* blow away the last block accessed */
cp->last_tagset = 0;
cp->last_blk = NULL;
/* allocate data blocks */
cp->data = (byte_t *)calloc(nsets * assoc,
sizeof(struct cache_blk_t) +
(cp->balloc ? (bsize*sizeof(byte_t)) : 0));
if (!cp->data)
fatal("out of virtual memory");
/* slice up the data blocks */
for (bindex=0,i=0; i<nsets; i++)
{
cp->sets[i].way_head = NULL;
cp->sets[i].way_tail = NULL;
/* get a hash table, if needed */
if (cp->hsize)
{
cp->sets[i].hash =
(struct cache_blk_t **)calloc(cp->hsize,
sizeof(struct cache_blk_t *));
if (!cp->sets[i].hash)
fatal("out of virtual memory");
}
/* NOTE: all the blocks in a set *must* be allocated contiguously,
otherwise, block accesses through SET->BLKS will fail (used
during random replacement selection) */
cp->sets[i].blks = CACHE_BINDEX(cp, cp->data, bindex);
/* link the data blocks into ordered way chain and hash table bucket
chains, if hash table exists */
for (j=0; j<assoc; j++)
{
/* locate next cache block */
blk = CACHE_BINDEX(cp, cp->data, bindex);
bindex++;
/* invalidate new cache block */
blk->status = 0;
blk->tag = 0;
blk->ready = 0;
blk->user_data = (usize != 0
? (byte_t *)calloc(usize, sizeof(byte_t)) : NULL);
/* insert cache block into set hash table */
if (cp->hsize)
link_htab_ent(cp, &cp->sets[i], blk);
/* insert into head of way list, order is arbitrary at this point */
blk->way_next = cp->sets[i].way_head;
blk->way_prev = NULL;
if (cp->sets[i].way_head)
cp->sets[i].way_head->way_prev = blk;
cp->sets[i].way_head = blk;
if (!cp->sets[i].way_tail)
cp->sets[i].way_tail = blk;
}
}
return cp;
}
/* parse policy */
enum cache_policy /* replacement policy enum */
cache_char2policy(char c) /* replacement policy as a char */
{
switch (c) {
case 'l': return LRU;
case 'r': return Random;
case 'f': return FIFO;
default: fatal("bogus replacement policy, `%c'", c);
}
}
/* print cache configuration */
void
cache_config(struct cache_t *cp, /* cache instance */
FILE *stream) /* output stream */
{
fprintf(stream,
"cache: %s: %d sets, %d byte blocks, %d bytes user data/block\n",
cp->name, cp->nsets, cp->bsize, cp->usize);
fprintf(stream,
"cache: %s: %d-way, `%s' replacement policy, write-back\n",
cp->name, cp->assoc,
cp->policy == LRU ? "LRU"
: cp->policy == Random ? "Random"
: cp->policy == FIFO ? "FIFO"
: (abort(), ""));
}
/* register cache stats */
void
cache_reg_stats(struct cache_t *cp, /* cache instance */
struct stat_sdb_t *sdb) /* stats database */
{
char buf[512], buf1[512], *name;
/* get a name for this cache */
if (!cp->name || !cp->name[0])
name = "<unknown>";
else
name = cp->name;
sprintf(buf, "%s.accesses", name);
sprintf(buf1, "%s.hits + %s.misses", name, name);
stat_reg_formula(sdb, buf, "total number of accesses", buf1, "%12.0f");
sprintf(buf, "%s.hits", name);
stat_reg_counter(sdb, buf, "total number of hits", &cp->hits, 0, NULL);
sprintf(buf, "%s.misses", name);
stat_reg_counter(sdb, buf, "total number of misses", &cp->misses, 0, NULL);
sprintf(buf, "%s.replacements", name);
stat_reg_counter(sdb, buf, "total number of replacements",
&cp->replacements, 0, NULL);
sprintf(buf, "%s.writebacks", name);
stat_reg_counter(sdb, buf, "total number of writebacks",
&cp->writebacks, 0, NULL);
sprintf(buf, "%s.invalidations", name);
stat_reg_counter(sdb, buf, "total number of invalidations",
&cp->invalidations, 0, NULL);
sprintf(buf, "%s.miss_rate", name);
sprintf(buf1, "%s.misses / %s.accesses", name, name);
stat_reg_formula(sdb, buf, "miss rate (i.e., misses/ref)", buf1, NULL);
sprintf(buf, "%s.repl_rate", name);
sprintf(buf1, "%s.replacements / %s.accesses", name, name);
stat_reg_formula(sdb, buf, "replacement rate (i.e., repls/ref)", buf1, NULL);
sprintf(buf, "%s.wb_rate", name);
sprintf(buf1, "%s.writebacks / %s.accesses", name, name);
stat_reg_formula(sdb, buf, "writeback rate (i.e., wrbks/ref)", buf1, NULL);
sprintf(buf, "%s.inv_rate", name);
sprintf(buf1, "%s.invalidations / %s.accesses", name, name);
stat_reg_formula(sdb, buf, "invalidation rate (i.e., invs/ref)", buf1, NULL);
}
/* print cache stats */
void
cache_stats(struct cache_t *cp, /* cache instance */
FILE *stream) /* output stream */
{
double sum = (double)(cp->hits + cp->misses);
fprintf(stream,
"cache: %s: %.0f hits %.0f misses %.0f repls %.0f invalidations\n",
cp->name, (double)cp->hits, (double)cp->misses,
(double)cp->replacements, (double)cp->invalidations);
fprintf(stream,
"cache: %s: miss rate=%f repl rate=%f invalidation rate=%f\n",
cp->name,
(double)cp->misses/sum, (double)(double)cp->replacements/sum,
(double)cp->invalidations/sum);
}
/* access a cache, perform a CMD operation on cache CP at address ADDR,
places NBYTES of data at *P, returns latency of operation if initiated
at NOW, places pointer to block user data in *UDATA, *P is untouched if
cache blocks are not allocated (!CP->BALLOC), UDATA should be NULL if no
user data is attached to blocks */
unsigned int /* latency of access in cycles */
cache_access(struct cache_t *cp, /* cache to access */
enum mem_cmd cmd, /* access type, Read or Write */
md_addr_t addr, /* address of access */
void *vp, /* ptr to buffer for input/output */
int nbytes, /* number of bytes to access */
tick_t now, /* time of access */
byte_t **udata, /* for return of user data ptr */
md_addr_t *repl_addr) /* for address of replaced block */
{
byte_t *p = vp;
md_addr_t tag = CACHE_TAG(cp, addr);
md_addr_t set = CACHE_SET(cp, addr);
md_addr_t bofs = CACHE_BLK(cp, addr);
struct cache_blk_t *blk, *repl;
int lat = 0;
/* default replacement address */
if (repl_addr)
*repl_addr = 0;
/* check alignments */
if ((nbytes & (nbytes-1)) != 0 || (addr & (nbytes-1)) != 0)
fatal("cache: access error: bad size or alignment, addr 0x%08x", addr);
/* access must fit in cache block */
/* FIXME:
((addr + (nbytes - 1)) > ((addr & ~cp->blk_mask) + (cp->bsize - 1))) */
if ((addr + nbytes) > ((addr & ~cp->blk_mask) + cp->bsize))
fatal("cache: access error: access spans block, addr 0x%08x", addr);
/* permissions are checked on cache misses */
/* check for a fast hit: access to same block */
if (CACHE_TAGSET(cp, addr) == cp->last_tagset)
{
/* hit in the same block */
blk = cp->last_blk;
goto cache_fast_hit;
}
if (cp->hsize)
{
/* higly-associativity cache, access through the per-set hash tables */
int hindex = CACHE_HASH(cp, tag);
for (blk=cp->sets[set].hash[hindex];
blk;
blk=blk->hash_next)
{
if (blk->tag == tag && (blk->status & CACHE_BLK_VALID))
goto cache_hit;
}
}
else
{
/* low-associativity cache, linear search the way list */
for (blk=cp->sets[set].way_head;
blk;
blk=blk->way_next)
{
if (blk->tag == tag && (blk->status & CACHE_BLK_VALID))
goto cache_hit;
}
}
/* cache block not found */
/* **MISS** */
cp->misses++;
/* select the appropriate block to replace, and re-link this entry to
the appropriate place in the way list */
switch (cp->policy) {
case LRU:
case FIFO:
repl = cp->sets[set].way_tail;
update_way_list(&cp->sets[set], repl, Head);
break;
case Random:
{
int bindex = myrand() & (cp->assoc - 1);
repl = CACHE_BINDEX(cp, cp->sets[set].blks, bindex);
}
break;
default:
panic("bogus replacement policy");
}
/* remove this block from the hash bucket chain, if hash exists */
if (cp->hsize)
unlink_htab_ent(cp, &cp->sets[set], repl);
/* blow away the last block to hit */
cp->last_tagset = 0;
cp->last_blk = NULL;
/* write back replaced block data */
if (repl->status & CACHE_BLK_VALID)
{
cp->replacements++;
if (repl_addr)
*repl_addr = CACHE_MK_BADDR(cp, repl->tag, set);
/* don't replace the block until outstanding misses are satisfied */
lat += BOUND_POS(repl->ready - now);
/* stall until the bus to next level of memory is available */
lat += BOUND_POS(cp->bus_free - (now + lat));
/* track bus resource usage */
cp->bus_free = MAX(cp->bus_free, (now + lat)) + 1;
if (repl->status & CACHE_BLK_DIRTY)
{
/* write back the cache block */
cp->writebacks++;
lat += cp->blk_access_fn(Write,
CACHE_MK_BADDR(cp, repl->tag, set),
cp->bsize, repl, now+lat);
}
}
/* update block tags */
repl->tag = tag;
repl->status = CACHE_BLK_VALID; /* dirty bit set on update */
/* read data block */
lat += cp->blk_access_fn(Read, CACHE_BADDR(cp, addr), cp->bsize,
repl, now+lat);
/* copy data out of cache block */
if (cp->balloc)
{
CACHE_BCOPY(cmd, repl, bofs, p, nbytes);
}
/* update dirty status */
if (cmd == Write)
repl->status |= CACHE_BLK_DIRTY;
/* get user block data, if requested and it exists */
if (udata)
*udata = repl->user_data;
/* update block status */
repl->ready = now+lat;
/* link this entry back into the hash table */
if (cp->hsize)
link_htab_ent(cp, &cp->sets[set], repl);
/* return latency of the operation */
return lat;
cache_hit: /* slow hit handler */
/* **HIT** */
cp->hits++;
/* copy data out of cache block, if block exists */
if (cp->balloc)
{
CACHE_BCOPY(cmd, blk, bofs, p, nbytes);
}
/* update dirty status */
if (cmd == Write)
blk->status |= CACHE_BLK_DIRTY;
/* if LRU replacement and this is not the first element of list, reorder */
if (blk->way_prev && cp->policy == LRU)
{
/* move this block to head of the way (MRU) list */
update_way_list(&cp->sets[set], blk, Head);
}
/* tag is unchanged, so hash links (if they exist) are still valid */
/* record the last block to hit */
cp->last_tagset = CACHE_TAGSET(cp, addr);
cp->last_blk = blk;
/* get user block data, if requested and it exists */
if (udata)
*udata = blk->user_data;
/* return first cycle data is available to access */
return (int) MAX(cp->hit_latency, (blk->ready - now));
cache_fast_hit: /* fast hit handler */
/* **FAST HIT** */
cp->hits++;
/* copy data out of cache block, if block exists */
if (cp->balloc)
{
CACHE_BCOPY(cmd, blk, bofs, p, nbytes);
}
/* update dirty status */
if (cmd == Write)
blk->status |= CACHE_BLK_DIRTY;
/* this block hit last, no change in the way list */
/* tag is unchanged, so hash links (if they exist) are still valid */
/* get user block data, if requested and it exists */
if (udata)
*udata = blk->user_data;
/* record the last block to hit */
cp->last_tagset = CACHE_TAGSET(cp, addr);
cp->last_blk = blk;
/* return first cycle data is available to access */
return (int) MAX(cp->hit_latency, (blk->ready - now));
}
/* return non-zero if block containing address ADDR is contained in cache
CP, this interface is used primarily for debugging and asserting cache
invariants */
int /* non-zero if access would hit */
cache_probe(struct cache_t *cp, /* cache instance to probe */
md_addr_t addr) /* address of block to probe */
{
md_addr_t tag = CACHE_TAG(cp, addr);
md_addr_t set = CACHE_SET(cp, addr);
struct cache_blk_t *blk;
/* permissions are checked on cache misses */
if (cp->hsize)
{
/* higly-associativity cache, access through the per-set hash tables */
int hindex = CACHE_HASH(cp, tag);
for (blk=cp->sets[set].hash[hindex];
blk;
blk=blk->hash_next)
{
if (blk->tag == tag && (blk->status & CACHE_BLK_VALID))
return TRUE;
}
}
else
{
/* low-associativity cache, linear search the way list */
for (blk=cp->sets[set].way_head;
blk;
blk=blk->way_next)
{
if (blk->tag == tag && (blk->status & CACHE_BLK_VALID))
return TRUE;
}
}
/* cache block not found */
return FALSE;
}
/* flush the entire cache, returns latency of the operation */
unsigned int /* latency of the flush operation */
cache_flush(struct cache_t *cp, /* cache instance to flush */
tick_t now) /* time of cache flush */
{
int i, lat = cp->hit_latency; /* min latency to probe cache */
struct cache_blk_t *blk;
/* blow away the last block to hit */
cp->last_tagset = 0;
cp->last_blk = NULL;
/* no way list updates required because all blocks are being invalidated */
for (i=0; i<cp->nsets; i++)
{
for (blk=cp->sets[i].way_head; blk; blk=blk->way_next)
{
if (blk->status & CACHE_BLK_VALID)
{
cp->invalidations++;
blk->status &= ~CACHE_BLK_VALID;
if (blk->status & CACHE_BLK_DIRTY)
{
/* write back the invalidated block */
cp->writebacks++;
lat += cp->blk_access_fn(Write,
CACHE_MK_BADDR(cp, blk->tag, i),
cp->bsize, blk, now+lat);
}
}
}
}
/* return latency of the flush operation */
return lat;
}
/* flush the block containing ADDR from the cache CP, returns the latency of
the block flush operation */
unsigned int /* latency of flush operation */
cache_flush_addr(struct cache_t *cp, /* cache instance to flush */
md_addr_t addr, /* address of block to flush */
tick_t now) /* time of cache flush */
{
md_addr_t tag = CACHE_TAG(cp, addr);
md_addr_t set = CACHE_SET(cp, addr);
struct cache_blk_t *blk;
int lat = cp->hit_latency; /* min latency to probe cache */
if (cp->hsize)
{
/* higly-associativity cache, access through the per-set hash tables */
int hindex = CACHE_HASH(cp, tag);
for (blk=cp->sets[set].hash[hindex];
blk;
blk=blk->hash_next)
{
if (blk->tag == tag && (blk->status & CACHE_BLK_VALID))
break;
}
}
else
{
/* low-associativity cache, linear search the way list */
for (blk=cp->sets[set].way_head;
blk;
blk=blk->way_next)
{
if (blk->tag == tag && (blk->status & CACHE_BLK_VALID))
break;
}
}
if (blk)
{
cp->invalidations++;
blk->status &= ~CACHE_BLK_VALID;
/* blow away the last block to hit */
cp->last_tagset = 0;
cp->last_blk = NULL;
if (blk->status & CACHE_BLK_DIRTY)
{
/* write back the invalidated block */
cp->writebacks++;
lat += cp->blk_access_fn(Write,
CACHE_MK_BADDR(cp, blk->tag, set),
cp->bsize, blk, now+lat);
}
/* move this block to tail of the way (LRU) list */
update_way_list(&cp->sets[set], blk, Tail);
}
/* return latency of the operation */
return lat;
}
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