Implement Hauser misa.C misalignment proposal (#187)

[riscv-isa-sim.git] / riscv / processor.cc

diff --git a/riscv/processor.cc b/riscv/processor.cc
index 5a57c285c9bcada230568c2bc76991987c8a9fd3..548c649cd2fafd76fe92bb8929544cffac7d8433 100644 (file)
--- a/riscv/processor.cc
+++ b/riscv/processor.cc
@@ -155,7 +155,8 @@ void processor_t::reset()
   if (ext)
     ext->reset(); // reset the extension
 
-  sim->proc_reset(id);
+  if (sim)
+    sim->proc_reset(id);
 }
 
 // Count number of contiguous 0 bits starting from the LSB.
@@ -449,6 +450,10 @@ void processor_t::set_csr(int which, reg_t val)
     case CSR_MCAUSE: state.mcause = val; break;
     case CSR_MTVAL: state.mtval = val; break;
     case CSR_MISA: {
+      // the write is ignored if increasing IALIGN would misalign the PC
+      if (!(val & (1L << ('C' - 'A'))) && (state.pc & 2))
+        break;
+
       if (!(val & (1L << ('F' - 'A'))))
         val &= ~(1L << ('D' - 'A'));
 
@@ -591,7 +596,7 @@ reg_t processor_t::get_csr(int which)
     }
     case CSR_SIP: return state.mip & state.mideleg;
     case CSR_SIE: return state.mie & state.mideleg;
-    case CSR_SEPC: return state.sepc;
+    case CSR_SEPC: return state.sepc & pc_alignment_mask();
     case CSR_STVAL: return state.stval;
     case CSR_STVEC: return state.stvec;
     case CSR_SCAUSE:
@@ -606,7 +611,7 @@ reg_t processor_t::get_csr(int which)
     case CSR_MSTATUS: return state.mstatus;
     case CSR_MIP: return state.mip;
     case CSR_MIE: return state.mie;
-    case CSR_MEPC: return state.mepc;
+    case CSR_MEPC: return state.mepc & pc_alignment_mask();
     case CSR_MSCRATCH: return state.mscratch;
     case CSR_MCAUSE: return state.mcause;
     case CSR_MTVAL: return state.mtval;
@@ -667,7 +672,7 @@ reg_t processor_t::get_csr(int which)
         return v;
       }
     case CSR_DPC:
-      return state.dpc;
+      return state.dpc & pc_alignment_mask();
     case CSR_DSCRATCH:
       return state.dscratch;
   }