Add debug access to rword and friends to allow read data through cache without disturbing statistic.

This allows to switch view between CPU and raw memory content.

Signed-off-by: Pavel Pisa <pisa@cmp.felk.cvut.cz>

8 files changed, 82 insertions, 49 deletions

diff --git a/qtmips_machine/cache.cpp b/qtmips_machine/cache.cpp
index 742cdb5..30771b0 100644
--- a/qtmips_machine/cache.cpp
+++ b/qtmips_machine/cache.cpp
@@ -75,15 +75,17 @@ Cache::Cache(MemoryAccess  *m, const MachineConfigCache *cc, unsigned memory_acc
             replc.lfu[row] = new unsigned[cnf.associativity()];
             for (unsigned int  i = 0; i < cnf.associativity(); i++)
                  replc.lfu[row][i] = 0;
-	}
+        }
         break;
     case MachineConfigCache::RP_LRU:
-        replc.lru = new time_t*[cnf.sets()];
+        replc.lru = new unsigned int*[cnf.sets()];
         for (unsigned int row = 0; row < cnf.sets(); row++) {
-            replc.lru[row] = new time_t[cnf.associativity()];
+            replc.lru[row] = new unsigned int[cnf.associativity()];
             for (unsigned int i = 0; i < cnf.associativity(); i++)
                 replc.lru[row][i] = 0;
-	}
+        }
+        break;
+    case MachineConfigCache::RP_RAND:
     default:
         break;
     }
@@ -138,12 +140,17 @@ bool Cache::wword(std::uint32_t address, std::uint32_t value) {
     return changed;
 }
 
-std::uint32_t Cache::rword(std::uint32_t address) const {
+std::uint32_t Cache::rword(std::uint32_t address, bool debug_access) const {
     if (!cnf.enabled() ||
         (address >= uncached_start && address <= uncached_last)) {
-        return mem->read_word(address);
+        return mem->read_word(address, debug_access);
     }
 
+    if (debug_access) {
+        if (!(location_status(address) & LOCSTAT_CACHED))
+            return mem->read_word(address, debug_access);
+        return debug_rword(address);
+    }
     std::uint32_t data;
     access(address, &data, false);
     return data;
@@ -236,16 +243,25 @@ enum LocationStatus Cache::location_status(std::uint32_t address) const {
     return mem->location_status(address);
 }
 
+std::uint32_t Cache::debug_rword(std::uint32_t address) const {
+    std::uint32_t row, col, tag;
+    compute_row_col_tag(row, col, tag, address);
+    for (unsigned indx = 0; indx < cnf.associativity(); indx++)
+        if (dt[indx][row].valid && dt[indx][row].tag == tag)
+            return dt[indx][row].data[col];
+    return 0;
+}
+
 bool Cache::access(std::uint32_t address, std::uint32_t *data, bool write, std::uint32_t value) const {
     bool changed = false;
     std::uint32_t row, col, tag;
     compute_row_col_tag(row, col, tag, address);
 
     unsigned indx = 0;
-    // Try to locate exact block or some unused one
-    while (indx < cnf.associativity() && dt[indx][row].valid && dt[indx][row].tag != tag)
+    // Try to locate exact block
+    while (indx < cnf.associativity() && (!dt[indx][row].valid || dt[indx][row].tag != tag))
         indx++;
-    // Replace block
+    // Need to find new block
     if (indx >= cnf.associativity()) {
         // We have to kick something
         switch (cnf.replacement_policy()) {
@@ -254,26 +270,37 @@ bool Cache::access(std::uint32_t address, std::uint32_t *data, bool write, std::
             break;
         case MachineConfigCache::RP_LFU:
             {
-            unsigned lowest = replc.lfu[row][0];
-            indx = 0;
-            for (unsigned i = 1; i < cnf.associativity(); i++)
-                if (lowest > replc.lfu[row][i]) {
-                    lowest = replc.lfu[row][i];
-                    indx = i;
+                unsigned lowest = replc.lfu[row][0];
+                indx = 0;
+                for (unsigned i = 1; i < cnf.associativity(); i++) {
+                    if (!dt[i][row].valid) {
+                        indx = i;
+                        break;
+                    }
+                    if (lowest > replc.lfu[row][i]) {
+                        lowest = replc.lfu[row][i];
+                        indx = i;
+                    }
                 }
+                break;
             }
-            break;
         case MachineConfigCache::RP_LRU:
             {
-            time_t lowest = replc.lru[row][0];
-            indx = 0;
-            for (unsigned i = 1; i < cnf.associativity(); i++)
-                if (lowest > replc.lru[row][i]) {
-                    lowest = replc.lru[row][i];
-                    indx = i;
+                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;
             }
-            break;
         }
     }
     SANITY_ASSERT(indx < cnf.associativity(), "Probably unimplemented replacement policy");
@@ -307,13 +334,17 @@ bool Cache::access(std::uint32_t address, std::uint32_t *data, bool write, std::
         }
     }
 
-    // Update replc
+    // Update replcement data
     switch (cnf.replacement_policy()) {
     case MachineConfigCache::RP_LFU:
-        replc.lru[row][indx]++;
+        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:
-        replc.lfu[row][indx] = time(NULL);
+        replc.lfu[row][indx]++;
         break;
     default:
         break;
@@ -345,7 +376,6 @@ void Cache::kick(unsigned associat_indx, unsigned row) const {
 
     switch (cnf.replacement_policy()) {
     case MachineConfigCache::RP_LFU:
-        replc.lru[row][associat_indx] = 0;
         break;
     default:
         break;
diff --git a/qtmips_machine/cache.h b/qtmips_machine/cache.h
index d08e66a..200f3ce 100644
--- a/qtmips_machine/cache.h
+++ b/qtmips_machine/cache.h
@@ -50,7 +50,7 @@ public:
     ~Cache();
 
     bool wword(std::uint32_t address, std::uint32_t value);
-    std::uint32_t rword(std::uint32_t address) const;
+    std::uint32_t rword(std::uint32_t address, bool debug_access = false) const;
 
     void flush(); // flush cache
     void sync(); // Same as flush
@@ -91,12 +91,13 @@ private:
     mutable struct cache_data **dt;
 
     union {
-        time_t ** lru; // Access time
+        unsigned int ** lru; // Access time
         unsigned **lfu; // Access count
     } replc; // Data used for replacement policy
 
     mutable unsigned hit_read, miss_read, hit_write, miss_write; // Hit and miss counters
 
+    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;
     void kick(unsigned associat_indx, unsigned row) const;
     std::uint32_t base_address(std::uint32_t tag, unsigned row) const;
diff --git a/qtmips_machine/memory.cpp b/qtmips_machine/memory.cpp
index af9420b..848669d 100644
--- a/qtmips_machine/memory.cpp
+++ b/qtmips_machine/memory.cpp
@@ -61,18 +61,18 @@ bool MemoryAccess::write_word(std::uint32_t offset, std::uint32_t value) {
     return wword(offset, value);
 }
 
-std::uint8_t MemoryAccess::read_byte(std::uint32_t offset) const {
+std::uint8_t MemoryAccess::read_byte(std::uint32_t offset, bool debug_access) const {
     int nth = SH_NTH_8(offset);
-    return (std::uint8_t)(rword(offset) >> nth);
+    return (std::uint8_t)(rword(offset, debug_access) >> nth);
 }
 
-std::uint16_t MemoryAccess::read_hword(std::uint32_t offset) const {
+std::uint16_t MemoryAccess::read_hword(std::uint32_t offset, bool debug_access) const {
     int nth = SH_NTH_16(offset);
-    return (std::uint16_t)(rword(offset) >> nth);
+    return (std::uint16_t)(rword(offset, debug_access) >> nth);
 }
 
-std::uint32_t MemoryAccess::read_word(std::uint32_t offset) const {
-    return rword(offset);
+std::uint32_t MemoryAccess::read_word(std::uint32_t offset, bool debug_access) const {
+    return rword(offset, debug_access);
 }
 
 void MemoryAccess::write_ctl(enum AccessControl ctl, std::uint32_t offset, std::uint32_t value) {
@@ -151,7 +151,8 @@ bool MemorySection::wword(std::uint32_t offset, std::uint32_t value) {
     return changed;
 }
 
-std::uint32_t MemorySection::rword(std::uint32_t offset) const {
+std::uint32_t MemorySection::rword(std::uint32_t offset, bool debug_access) const {
+    (void)debug_access;
     offset = offset >> 2;
     if (offset >= this->len)
         throw QTMIPS_EXCEPTION(OutOfMemoryAccess, "Trying to read outside of the memory section", QString("Accessing using offset: ") + QString(offset));
@@ -263,12 +264,12 @@ bool Memory::wword(std::uint32_t address, std::uint32_t value) {
     return changed;
 }
 
-std::uint32_t Memory::rword(std::uint32_t address) const {
+std::uint32_t Memory::rword(std::uint32_t address, bool debug_access) const {
     MemorySection *section = this->get_section(address, false);
     if (section == nullptr)
         return 0;
     else
-        return section->read_word(SECTION_OFFSET_MASK(address));
+        return section->read_word(SECTION_OFFSET_MASK(address), debug_access);
 }
 
 bool Memory::operator==(const Memory&m) const {
diff --git a/qtmips_machine/memory.h b/qtmips_machine/memory.h
index 33caf46..b354c4c 100644
--- a/qtmips_machine/memory.h
+++ b/qtmips_machine/memory.h
@@ -52,9 +52,9 @@ public:
     bool write_hword(std::uint32_t offset, std::uint16_t value);
     bool write_word(std::uint32_t offset, std::uint32_t value);
 
-    std::uint8_t read_byte(std::uint32_t offset) const;
-    std::uint16_t read_hword(std::uint32_t offset) const;
-    std::uint32_t read_word(std::uint32_t offset) const;
+    std::uint8_t read_byte(std::uint32_t offset, bool debug_access = false) const;
+    std::uint16_t read_hword(std::uint32_t offset, bool debug_access = false) const;
+    std::uint32_t read_word(std::uint32_t offset, bool debug_access = false) const;
 
     void write_ctl(enum AccessControl ctl, std::uint32_t offset, std::uint32_t value);
     std::uint32_t read_ctl(enum AccessControl ctl, std::uint32_t offset) const;
@@ -64,7 +64,7 @@ public:
 
 protected:
     virtual bool wword(std::uint32_t offset, std::uint32_t value) = 0;
-    virtual std::uint32_t rword(std::uint32_t offset) const = 0;
+    virtual std::uint32_t rword(std::uint32_t offset, bool debug_access = false) const = 0;
 
 private:
     static int sh_nth(std::uint32_t offset);
@@ -77,7 +77,7 @@ public:
     ~MemorySection();
 
     bool wword(std::uint32_t offset, std::uint32_t value);
-    std::uint32_t rword(std::uint32_t offset) const;
+    std::uint32_t rword(std::uint32_t offsetbool, bool debug_access = false) const;
     void merge(MemorySection&);
 
     std::uint32_t length() const;
@@ -107,7 +107,7 @@ public:
 
     MemorySection *get_section(std::uint32_t address, bool create) const; // returns section containing given address
     bool wword(std::uint32_t address, std::uint32_t value);
-    std::uint32_t rword(std::uint32_t address) const;
+    std::uint32_t rword(std::uint32_t address, bool debug_access = false) const;
 
     bool operator==(const Memory&) const;
     bool operator!=(const Memory&) const;
diff --git a/qtmips_machine/peripheral.cpp b/qtmips_machine/peripheral.cpp
index ac74c2a..9e922b8 100644
--- a/qtmips_machine/peripheral.cpp
+++ b/qtmips_machine/peripheral.cpp
@@ -55,7 +55,8 @@ bool SimplePeripheral::wword(std::uint32_t address, std::uint32_t value) {
     return true;
 }
 
-std::uint32_t SimplePeripheral::rword(std::uint32_t address) const {
+std::uint32_t SimplePeripheral::rword(std::uint32_t address, bool debug_access) const {
+    (void)debug_access;
     std::uint32_t value = 0x12345678;
 #if 0
     printf("SimplePeripheral::rword address 0x%08lx\n",
diff --git a/qtmips_machine/peripheral.h b/qtmips_machine/peripheral.h
index 92df1d7..0effd47 100644
--- a/qtmips_machine/peripheral.h
+++ b/qtmips_machine/peripheral.h
@@ -57,7 +57,7 @@ signals:
 
 public:
     bool wword(std::uint32_t address, std::uint32_t value);
-    std::uint32_t rword(std::uint32_t address) const;
+    std::uint32_t rword(std::uint32_t address, bool debug_access = false) const;
 };
 
 }
diff --git a/qtmips_machine/physaddrspace.cpp b/qtmips_machine/physaddrspace.cpp
index bb01b60..4d0045c 100644
--- a/qtmips_machine/physaddrspace.cpp
+++ b/qtmips_machine/physaddrspace.cpp
@@ -59,11 +59,11 @@ bool PhysAddrSpace::wword(std::uint32_t address, std::uint32_t value) {
     return p_range->mem_acces->write_word(address - p_range->start_addr, value);
 }
 
-std::uint32_t PhysAddrSpace::rword(std::uint32_t address) const {
+std::uint32_t PhysAddrSpace::rword(std::uint32_t address, bool debug_access) const {
     const RangeDesc *p_range = find_range(address);
     if (p_range == nullptr)
         return 0x00000000;
-    return p_range->mem_acces->read_word(address - p_range->start_addr);
+    return p_range->mem_acces->read_word(address - p_range->start_addr, debug_access);
 }
 
 enum LocationStatus PhysAddrSpace::location_status(std::uint32_t address) const {
diff --git a/qtmips_machine/physaddrspace.h b/qtmips_machine/physaddrspace.h
index c6f5e81..9c13e07 100644
--- a/qtmips_machine/physaddrspace.h
+++ b/qtmips_machine/physaddrspace.h
@@ -52,7 +52,7 @@ public:
     ~PhysAddrSpace();
 
     bool wword(std::uint32_t address, std::uint32_t value);
-    std::uint32_t rword(std::uint32_t address) const;
+    std::uint32_t rword(std::uint32_t address, bool debug_access = false) const;
 
     bool insert_range(MemoryAccess *mem_acces, std::uint32_t start_addr, std::uint32_t last_addr, bool move_ownership);
     bool remove_range(MemoryAccess *mem_acces);