TSR is read-only 0 when S-mode is not supported. (#890)

According the privileged spec, TSR is read-only 0 when S-mode is not supported. (56515289e5/src/machine.tex (L860-L861))
4 years ago · d1f2019ec1
1 changed files with 2 additions and 1 deletions
--- a/riscv/csrs.cc
+++ b/riscv/csrs.cc
@ -439,7 +439,8 @@ bool mstatus_csr_t::unlogged_write(const reg_t val) noexcept {

  const reg_t mask = sstatus_write_mask
                   | MSTATUS_MIE | MSTATUS_MPIE | MSTATUS_MPRV
-                   | MSTATUS_MPP | MSTATUS_TW | MSTATUS_TSR
+                   | MSTATUS_MPP | MSTATUS_TW
+                   | (proc->extension_enabled('S') ? MSTATUS_TSR : 0)
                   | (has_page ? MSTATUS_TVM : 0)
                   | (has_gva ? MSTATUS_GVA : 0)
                   | (has_mpv ? MSTATUS_MPV : 0);