diff options
Diffstat (limited to 'qtmips_machine')
| -rw-r--r-- | qtmips_machine/cache.cpp | 70 | ||||
| -rw-r--r-- | qtmips_machine/cache.h | 4 |
2 files changed, 41 insertions, 33 deletions
diff --git a/qtmips_machine/cache.cpp b/qtmips_machine/cache.cpp index 30771b0..231aa81 100644 --- a/qtmips_machine/cache.cpp +++ b/qtmips_machine/cache.cpp @@ -51,7 +51,7 @@ Cache::Cache(MemoryAccess *m, const MachineConfigCache *cc, unsigned memory_acc dt = nullptr; replc.lfu = nullptr; replc.lru = nullptr; - p_change_counter = new std::uint32_t(0); + change_counter = 0; // Skip any other initialization if cache is disabled if (!cc->enabled()) @@ -82,7 +82,7 @@ Cache::Cache(MemoryAccess *m, const MachineConfigCache *cc, unsigned memory_acc for (unsigned int row = 0; row < cnf.sets(); row++) { replc.lru[row] = new unsigned int[cnf.associativity()]; for (unsigned int i = 0; i < cnf.associativity(); i++) - replc.lru[row][i] = 0; + replc.lru[row][i] = i; } break; case MachineConfigCache::RP_RAND: @@ -92,7 +92,6 @@ Cache::Cache(MemoryAccess *m, const MachineConfigCache *cc, unsigned memory_acc } Cache::~Cache(){ - delete p_change_counter; if (dt != nullptr) { for (unsigned i = 0; i < cnf.associativity(); i++) { if (dt[i]) { @@ -160,7 +159,7 @@ void Cache::flush() { if (!cnf.enabled()) return; - for (unsigned as = 0; as < cnf.associativity(); as++) + for (unsigned as = cnf.associativity(); as-- > 0 ; ) for (unsigned st = 0; st < cnf.sets(); st++) if (dt[as][st].valid) kick(as, st); @@ -268,6 +267,11 @@ bool Cache::access(std::uint32_t address, std::uint32_t *data, bool write, std:: case MachineConfigCache::RP_RAND: indx = rand() % cnf.associativity(); break; + case MachineConfigCache::RP_LRU: + { + indx = replc.lru[row][0]; + break; + } case MachineConfigCache::RP_LFU: { unsigned lowest = replc.lfu[row][0]; @@ -284,23 +288,6 @@ bool Cache::access(std::uint32_t address, std::uint32_t *data, bool write, std:: } break; } - case MachineConfigCache::RP_LRU: - { - unsigned int least = 0xffff; - indx = 0; - for (unsigned i = 0; i < cnf.associativity(); i++) { - if (!dt[i][row].valid) { - // found free one, use it directly - indx = i; - break; - } - if (least < replc.lru[row][i]) { - least = replc.lru[row][i]; - indx = i; - } - } - break; - } } } SANITY_ASSERT(indx < cnf.associativity(), "Probably unimplemented replacement policy"); @@ -310,7 +297,7 @@ bool Cache::access(std::uint32_t address, std::uint32_t *data, bool write, std:: // Verify if we are not replacing if (cd.valid && cd.tag != tag) { kick(indx, row); - (*p_change_counter)++; + change_counter++; } // Update statistics and otherwise read from memory @@ -330,20 +317,27 @@ bool Cache::access(std::uint32_t address, std::uint32_t *data, bool write, std:: update_statistics(); for (unsigned i = 0; i < cnf.blocks(); i++) { cd.data[i] = mem->read_word(base_address(tag, row) + (4*i)); - (*p_change_counter)++; + change_counter++; } } // Update replcement data switch (cnf.replacement_policy()) { - case MachineConfigCache::RP_LFU: - if (cd.valid && replc.lru[row][indx] == 0) - break; - for (unsigned i = 1; i < cnf.associativity(); i++) - replc.lru[row][i]++; - replc.lru[row][indx] = 0; - break; case MachineConfigCache::RP_LRU: + { + unsigned next_asi = indx; + int i = cnf.associativity() - 1; + unsigned tmp_asi = replc.lru[row][i]; + while (tmp_asi != indx) { + SANITY_ASSERT(i >= 0, "LRU lost the way from priority queue - access"); + tmp_asi = replc.lru[row][i]; + replc.lru[row][i] = next_asi; + next_asi = tmp_asi; + i--; + } + break; + } + case MachineConfigCache::RP_LFU: replc.lfu[row][indx]++; break; default: @@ -362,7 +356,7 @@ bool Cache::access(std::uint32_t address, std::uint32_t *data, bool write, std:: emit cache_update(indx, row, cd.valid, cd.dirty, cd.tag, cd.data); if (changed) - (*p_change_counter)++; + change_counter++; return changed; } @@ -375,6 +369,20 @@ void Cache::kick(unsigned associat_indx, unsigned row) const { cd.dirty = false; switch (cnf.replacement_policy()) { + case MachineConfigCache::RP_LRU: + { + unsigned next_asi = associat_indx; + unsigned tmp_asi = replc.lru[row][0]; + int i = 1; + while (tmp_asi != associat_indx) { + SANITY_ASSERT(i < (int)cnf.associativity(), "LRU lost the way from priority queue - kick"); + tmp_asi = replc.lru[row][i]; + replc.lru[row][i] = next_asi; + next_asi = tmp_asi; + i++; + } + break; + } case MachineConfigCache::RP_LFU: break; default: diff --git a/qtmips_machine/cache.h b/qtmips_machine/cache.h index 200f3ce..827631b 100644 --- a/qtmips_machine/cache.h +++ b/qtmips_machine/cache.h @@ -67,7 +67,7 @@ public: enum LocationStatus location_status(std::uint32_t address) const; inline std::uint32_t get_change_counter() const { - return *p_change_counter; + return change_counter; } signals: void hit_update(unsigned) const; @@ -76,7 +76,6 @@ signals: void cache_update(unsigned associat, unsigned set, bool valid, bool dirty, std::uint32_t tag, const std::uint32_t *data) const; private: - std::uint32_t* p_change_counter; MachineConfigCache cnf; MemoryAccess *mem; unsigned access_pen_r, access_pen_w; @@ -96,6 +95,7 @@ private: } replc; // Data used for replacement policy mutable unsigned hit_read, miss_read, hit_write, miss_write; // Hit and miss counters + mutable std::uint32_t change_counter; std::uint32_t debug_rword(std::uint32_t address) const; bool access(std::uint32_t address, std::uint32_t *data, bool write, std::uint32_t value = 0) const; |