1 files changed, 55 insertions, 0 deletions
diff --git a/riscv/icsim.cc b/riscv/icsim.cc
new file mode 100644
index 0000000..73d6e9c
--- /dev/null
+++ b/riscv/icsim.cc
@@ -0,0 +1,55 @@
+#include "icsim.h"
+#include <stdexcept>
+#include <iostream>
+#include <iomanip>
+
+icsim_t::icsim_t(size_t _sets, size_t _ways, size_t _linesz)
+{
+  sets = _sets;
+  ways = _ways;
+  linesz = _linesz;
+
+  if(sets == 0 || (sets & (sets-1)))
+    throw std::logic_error("sets not a power of 2");
+  if(linesz == 0 || (linesz & (linesz-1)))
+    throw std::logic_error("linesz not a power of 2");
+  if(ways != 1)
+    throw std::logic_error("set associativity currently unsupported");
+
+  idx_mask = sets-1;
+  idx_shift = 0;
+  while(_linesz >>= 1)
+    idx_shift++;
+
+  tags = new uint64_t[sets*ways];
+  memset(tags, 0, sets*ways*sizeof(uint64_t));
+}
+
+icsim_t::~icsim_t()
+{
+  float mr = 100.0f*misses/accesses;
+  float cr = 100.0f*bytes_fetched/(4*accesses);
+
+  std::cout << "Instruction cache statsistics" << std::endl;
+  std::cout << "Bytes fetched: " << bytes_fetched << std::endl;
+  std::cout << "Hits: " << (accesses-misses) << std::endl;
+  std::cout << "Misses: " << misses << std::endl;
+  std::cout << "Miss rate: " << std::setprecision(3) << mr << '%' << std::endl;
+  std::cout << "RVC compression ratio: " << cr << '%' << std::endl;
+
+  delete [] tags;
+}
+
+void icsim_t::tick(uint64_t pc, int insnlen)
+{
+  accesses++;
+  bytes_fetched += insnlen;
+
+  size_t idx = (pc >> idx_shift) & idx_mask;
+  size_t tag = (pc >> idx_shift) | VALID;
+  if(tag != tags[idx])
+  {
+    misses++;
+    tags[idx] = tag;
+  }
+}