From b119073ab013f387000435ba5a55a3026fc8a8d9 Mon Sep 17 00:00:00 2001
From: Andrew Waterman <waterman@cs.berkeley.edu>
Date: Wed, 13 Feb 2013 12:59:53 -0800
Subject: add I$/D$/L2$ simulators

---
 riscv/cachesim.cc | 129 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 129 insertions(+)
 create mode 100644 riscv/cachesim.cc

(limited to 'riscv/cachesim.cc')

diff --git a/riscv/cachesim.cc b/riscv/cachesim.cc
new file mode 100644
index 0000000..d029c29
--- /dev/null
+++ b/riscv/cachesim.cc
@@ -0,0 +1,129 @@
+#include "cachesim.h"
+#include <cstdlib>
+#include <iostream>
+#include <iomanip>
+
+cache_sim_t::cache_sim_t(size_t _sets, size_t _ways, size_t _linesz, const char* _name)
+ : sets(_sets), ways(_ways), linesz(_linesz), name(_name)
+{
+  init();
+}
+
+static void help()
+{
+  std::cerr << "Cache configurations must be of the form" << std::endl;
+  std::cerr << "  sets:ways:blocksize" << std::endl;
+  std::cerr << "where sets, ways, and blocksize are positive integers, with" << std::endl;
+  std::cerr << "sets and blocksize both powers of two and blocksize at least 8." << std::endl;
+  exit(1);
+}
+
+cache_sim_t::cache_sim_t(const char* config, const char* _name)
+ : name(_name)
+{
+  const char* wp = strchr(config, ':');
+  if (!wp++) help();
+  const char* bp = strchr(wp, ':');
+  if (!bp++) help();
+
+  sets = atoi(std::string(config, wp).c_str());
+  ways = atoi(std::string(wp, bp).c_str());
+  linesz = atoi(bp);
+
+  init();
+}
+
+void cache_sim_t::init()
+{
+  if(sets == 0 || (sets & (sets-1)))
+    help();
+  if(linesz < 8 || (linesz & (linesz-1)))
+    help();
+
+  idx_shift = 0;
+  for (size_t x = linesz; x; x >>= 1)
+    idx_shift++;
+
+  tags = new uint64_t[sets*ways]();
+  read_accesses = 0;
+  read_misses = 0;
+  bytes_read = 0;
+  write_accesses = 0;
+  write_misses = 0;
+  bytes_written = 0;
+  writebacks = 0;
+
+  miss_handler = NULL;
+}
+
+cache_sim_t::cache_sim_t(const cache_sim_t& rhs)
+ : sets(rhs.sets), ways(rhs.ways), linesz(rhs.linesz),
+   idx_shift(rhs.idx_shift), name(rhs.name)
+{
+  tags = new uint64_t[sets*ways];
+  memcpy(tags, rhs.tags, sets*ways*sizeof(uint64_t));
+}
+
+cache_sim_t::~cache_sim_t()
+{
+  print_stats();
+  delete [] tags;
+}
+
+void cache_sim_t::print_stats()
+{
+  if(read_accesses + write_accesses == 0)
+    return;
+
+  float mr = 100.0f*(read_misses+write_misses)/(read_accesses+write_accesses);
+
+  std::cout << std::setprecision(3) << std::fixed;
+  std::cout << name << " ";
+  std::cout << "Bytes Read:            " << bytes_read << std::endl;
+  std::cout << name << " ";
+  std::cout << "Bytes Written:         " << bytes_written << std::endl;
+  std::cout << name << " ";
+  std::cout << "Read Accesses:         " << read_accesses << std::endl;
+  std::cout << name << " ";
+  std::cout << "Write Accesses:        " << write_accesses << std::endl;
+  std::cout << name << " ";
+  std::cout << "Read Misses:           " << read_misses << std::endl;
+  std::cout << name << " ";
+  std::cout << "Write Misses:          " << write_misses << std::endl;
+  std::cout << name << " ";
+  std::cout << "Writebacks:            " << writebacks << std::endl;
+  std::cout << name << " ";
+  std::cout << "Miss Rate:             " << mr << '%' << std::endl;
+}
+
+void cache_sim_t::access(uint64_t addr, size_t bytes, bool store)
+{
+  store ? write_accesses++ : read_accesses++;
+  (store ? bytes_written : bytes_read) += bytes;
+
+  size_t idx = (addr >> idx_shift) & (sets-1);
+  size_t tag = (addr >> idx_shift) | VALID;
+  size_t* set_tags = &tags[idx*ways];
+
+  for(size_t i = 0; i < ways; i++)
+  {
+    if(tag == (set_tags[i] & ~DIRTY)) // hit
+    {
+      if(store)
+        set_tags[i] |= DIRTY;
+      return;
+    }
+  }
+
+  store ? write_misses++ : read_misses++;
+
+  size_t way = lfsr.next() % ways;
+  if((set_tags[way] & (VALID | DIRTY)) == (VALID | DIRTY))
+  {
+    uint64_t dirty_addr = (set_tags[way] & ~(VALID | DIRTY)) << idx_shift;
+    if (miss_handler) miss_handler->access(dirty_addr, linesz, true);
+    writebacks++;
+  }
+  if (miss_handler) miss_handler->access(addr & ~(linesz-1), linesz, false);
+  set_tags[way] = tag | (store ? DIRTY : 0);
+}
-- 
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