modify minstret/mcycle/minstreth/mcycleh to reuse rv32_low/high_csr_t

3 files changed, 21 insertions, 44 deletions

diff --git a/riscv/csrs.cc b/riscv/csrs.cc
index 6f8f260..9721f87 100644
--- a/riscv/csrs.cc
+++ b/riscv/csrs.cc
@@ -515,6 +515,10 @@ bool rv32_low_csr_t::unlogged_write(const reg_t val) noexcept {
   return orig->unlogged_write((orig->written_value() >> 32 << 32) | (val & 0xffffffffU));
 }
 
+reg_t rv32_low_csr_t::written_value() const noexcept {
+  return orig->written_value() & 0xffffffffU;
+}
+
 // implement class rv32_high_csr_t
 rv32_high_csr_t::rv32_high_csr_t(processor_t* const proc, const reg_t addr, csr_t_p orig):
   csr_t(proc, addr),
@@ -533,6 +537,10 @@ bool rv32_high_csr_t::unlogged_write(const reg_t val) noexcept {
   return orig->unlogged_write((orig->written_value() << 32 >> 32) | ((val & 0xffffffffU) << 32));
 }
 
+reg_t rv32_high_csr_t::written_value() const noexcept {
+  return (orig->written_value() >> 32) & 0xffffffffU;
+}
+
 // implement class sstatus_csr_t
 sstatus_csr_t::sstatus_csr_t(processor_t* const proc, sstatus_proxy_csr_t_p orig, vsstatus_csr_t_p virt):
   virtualized_csr_t(proc, orig, virt),
@@ -924,10 +932,7 @@ void wide_counter_csr_t::bump(const reg_t howmuch) noexcept {
 }
 
 bool wide_counter_csr_t::unlogged_write(const reg_t val) noexcept {
-  if (proc->get_xlen() == 32)
-    this->val = (this->val >> 32 << 32) | (val & 0xffffffffU);
-  else
-    this->val = val;
+  this->val = val;
   // The ISA mandates that if an instruction writes instret, the write
   // takes precedence over the increment to instret.  However, Spike
   // unconditionally increments instret after executing an instruction.
@@ -941,27 +946,6 @@ reg_t wide_counter_csr_t::written_value() const noexcept {
   return this->val + 1;
 }
 
-void wide_counter_csr_t::write_upper_half(const reg_t val) noexcept {
-  this->val = (val << 32) | (this->val << 32 >> 32);
-  this->val--; // See comment above.
-  // Log upper half only.
-  log_special_write(address + (CSR_MINSTRETH - CSR_MINSTRET), written_value() >> 32);
-}
-
-counter_top_csr_t::counter_top_csr_t(processor_t* const proc, const reg_t addr, wide_counter_csr_t_p parent):
-  csr_t(proc, addr),
-  parent(parent) {
-}
-
-reg_t counter_top_csr_t::read() const noexcept {
-  return parent->read() >> 32;
-}
-
-bool counter_top_csr_t::unlogged_write(const reg_t val) noexcept {
-  parent->write_upper_half(val);
-  return true;
-}
-
 proxy_csr_t::proxy_csr_t(processor_t* const proc, const reg_t addr, csr_t_p delegate):
   csr_t(proc, addr),
   delegate(delegate) {
diff --git a/riscv/csrs.h b/riscv/csrs.h
index 500bde7..8108d1e 100644
--- a/riscv/csrs.h
+++ b/riscv/csrs.h
@@ -260,6 +260,7 @@ class rv32_low_csr_t: public csr_t {
   virtual void verify_permissions(insn_t insn, bool write) const override;
  protected:
   virtual bool unlogged_write(const reg_t val) noexcept override;
+  virtual reg_t written_value() const noexcept override;
  private:
   csr_t_p orig;
 };
@@ -271,6 +272,7 @@ class rv32_high_csr_t: public csr_t {
   virtual void verify_permissions(insn_t insn, bool write) const override;
  protected:
   virtual bool unlogged_write(const reg_t val) noexcept override;
+  virtual reg_t written_value() const noexcept override;
  private:
   csr_t_p orig;
 };
@@ -498,7 +500,6 @@ class wide_counter_csr_t: public csr_t {
   // Always returns full 64-bit value
   virtual reg_t read() const noexcept override;
   void bump(const reg_t howmuch) noexcept;
-  void write_upper_half(const reg_t val) noexcept;
  protected:
   virtual bool unlogged_write(const reg_t val) noexcept override;
   virtual reg_t written_value() const noexcept override;
@@ -508,19 +509,6 @@ class wide_counter_csr_t: public csr_t {
 
 typedef std::shared_ptr<wide_counter_csr_t> wide_counter_csr_t_p;
 
-// A simple proxy to read/write the upper half of minstret/mcycle
-class counter_top_csr_t: public csr_t {
- public:
-  counter_top_csr_t(processor_t* const proc, const reg_t addr, wide_counter_csr_t_p parent);
-  virtual reg_t read() const noexcept override;
- protected:
-  virtual bool unlogged_write(const reg_t val) noexcept override;
- private:
-  wide_counter_csr_t_p parent;
-};
-
-typedef std::shared_ptr<counter_top_csr_t> counter_top_csr_t_p;
-
 // For a CSR that is an alias of another
 class proxy_csr_t: public csr_t {
  public:
diff --git a/riscv/processor.cc b/riscv/processor.cc
index 8f77b47..c351d1d 100644
--- a/riscv/processor.cc
+++ b/riscv/processor.cc
@@ -202,20 +202,25 @@ void state_t::reset(processor_t* const proc, reg_t max_isa)
   csrmap[CSR_MSCRATCH] = std::make_shared<basic_csr_t>(proc, CSR_MSCRATCH, 0);
   csrmap[CSR_MTVEC] = mtvec = std::make_shared<tvec_csr_t>(proc, CSR_MTVEC);
   csrmap[CSR_MCAUSE] = mcause = std::make_shared<cause_csr_t>(proc, CSR_MCAUSE);
-  csrmap[CSR_MINSTRET] = minstret = std::make_shared<wide_counter_csr_t>(proc, CSR_MINSTRET);
-  csrmap[CSR_MCYCLE] = mcycle = std::make_shared<wide_counter_csr_t>(proc, CSR_MCYCLE);
+  minstret = std::make_shared<wide_counter_csr_t>(proc, CSR_MINSTRET);
+  mcycle = std::make_shared<wide_counter_csr_t>(proc, CSR_MCYCLE);
   if (proc->extension_enabled_const(EXT_ZICNTR)) {
     csrmap[CSR_INSTRET] = std::make_shared<counter_proxy_csr_t>(proc, CSR_INSTRET, minstret);
     csrmap[CSR_CYCLE] = std::make_shared<counter_proxy_csr_t>(proc, CSR_CYCLE, mcycle);
   }
   if (xlen == 32) {
-    counter_top_csr_t_p minstreth, mcycleh;
-    csrmap[CSR_MINSTRETH] = minstreth = std::make_shared<counter_top_csr_t>(proc, CSR_MINSTRETH, minstret);
-    csrmap[CSR_MCYCLEH] = mcycleh = std::make_shared<counter_top_csr_t>(proc, CSR_MCYCLEH, mcycle);
+    csr_t_p minstreth, mcycleh;
+    csrmap[CSR_MINSTRET] = std::make_shared<rv32_low_csr_t>(proc, CSR_MINSTRET, minstret);
+    csrmap[CSR_MINSTRETH] = minstreth = std::make_shared<rv32_high_csr_t>(proc, CSR_MINSTRETH, minstret);
+    csrmap[CSR_MCYCLE] = std::make_shared<rv32_low_csr_t>(proc, CSR_MCYCLE, mcycle);
+    csrmap[CSR_MCYCLEH] = mcycleh = std::make_shared<rv32_high_csr_t>(proc, CSR_MCYCLEH, mcycle);
     if (proc->extension_enabled_const(EXT_ZICNTR)) {
       csrmap[CSR_INSTRETH] = std::make_shared<counter_proxy_csr_t>(proc, CSR_INSTRETH, minstreth);
       csrmap[CSR_CYCLEH] = std::make_shared<counter_proxy_csr_t>(proc, CSR_CYCLEH, mcycleh);
     }
+  } else {
+    csrmap[CSR_MINSTRET] = minstret;
+    csrmap[CSR_MCYCLE] = mcycle;
   }
   for (reg_t i = 3; i <= 31; ++i) {
     const reg_t which_mevent = CSR_MHPMEVENT3 + i - 3;