new tohost/fromhost semantics

diff --git a/riscv/insns/mtpcr.h b/riscv/insns/mtpcr.h
index 5cd0134e0ba933c08df7daebe9b953354508b747..9b0beba15661037b5a739d5921a3c7c2a4eda65c 100644 (file)
--- a/riscv/insns/mtpcr.h
+++ b/riscv/insns/mtpcr.h
@@ -1,4 +1,5 @@
 require_supervisor;
 reg_t val = get_pcr(insn.rtype.rs1);
-set_pcr(insn.rtype.rs1, RS2);
+if (val == 0 || insn.rtype.rs1 != PCR_TOHOST)
+  set_pcr(insn.rtype.rs1, RS2);
 RD = val;

diff --git a/riscv/processor.cc b/riscv/processor.cc
index c11657556f6e2b3539c3319500dde2ad4aff4978..070ec15345eb568ab6b1bf49c871d52b2afc14fc 100644 (file)
--- a/riscv/processor.cc
+++ b/riscv/processor.cc
@@ -271,12 +271,10 @@ void processor_t::set_pcr(int which, reg_t val)
       vecbanks_count = __builtin_popcountll(vecbanks);
       break;
     case PCR_TOHOST:
-      fromhost = 0;
       tohost = val;
       break;
     case PCR_FROMHOST:
       fromhost = val;
-      tohost = 0;
       break;
   }
 }