fix(dbltrp): align logic of sdt with xiangshan

  * align vsstatus.sdt/henvcfg.DTE interaction logic with xiangshan
    * as vsstatus is not aliase of otther CSR fields and SDT is controlled
      by henvcfg.DTE. According to the manual, when the read/write property
      of **sdt** changes from **RO** to **RW**, its immediate value becomes
      **UNSPECIFIED** but valid. XiangShan adopts the simplest hardware
      implementation, allowing **vsstatus.sdt** to be written when **DTE**
      is disabled, while reads are masked by **DTE**. In contrast, Spike
      employs a design where both reads and writes are masked. To align the
      behavior of **vsstatus.sdt** in Spike with XiangShan during comparison,
      we adjust Spike's write behavior under **DTE**-disabled conditions to match XiangShan's.
  * add mstatus.sdt/sie, mstatus.mdt/mie missing interatcion logic.
    when sdt/mdt write 1, sie/mie will clear.

Author: lewislzh

riscv/csrs.cc

@@ -501,10 +501,21 @@ vsstatus_csr_t::vsstatus_csr_t(processor_t* const proc, const reg_t addr):
 
 bool vsstatus_csr_t::unlogged_write(const reg_t val) noexcept {
   const reg_t hDTE = (state->henvcfg->read() & HENVCFG_DTE);
-  const reg_t adj_write_mask = sstatus_write_mask & ~(hDTE ? 0 : SSTATUS_SDT);
+  const reg_t adj_write_mask =
+#if defined(DIFFTEST) && defined(CPU_XIANGSHAN)
+    sstatus_write_mask;
+#else
+    sstatus_write_mask & ~(hDTE ? 0 : SSTATUS_SDT);
+#endif
   reg_t newval = (this->val & ~adj_write_mask) | (val & adj_write_mask);
+  bool write_sdt =
+#if defined(DIFFTEST) && defined(CPU_XIANGSHAN)
+    newval & SSTATUS_SDT && hDTE;
+#else
+    (newval & SSTATUS_SDT);
+#endif
 
-  newval = (newval & SSTATUS_SDT) ? (newval & ~SSTATUS_SIE) : newval;
+  newval = (write_sdt) ? (newval & ~SSTATUS_SIE) : newval;
 
   if (state->v) maybe_flush_tlb(newval);
   this->val = adjust_sd(newval);
@@ -527,9 +538,7 @@ bool sstatus_proxy_csr_t::unlogged_write(const reg_t val) noexcept {
   const reg_t mDTE = (state->menvcfg->read() & MENVCFG_DTE);
   const reg_t adj_write_mask = sstatus_write_mask & ~(mDTE ? 0 : SSTATUS_SDT);
   reg_t new_mstatus = (mstatus->read() & ~adj_write_mask) | (val & adj_write_mask);
-
   new_mstatus = (new_mstatus & SSTATUS_SDT) ? (new_mstatus & ~SSTATUS_SIE) : new_mstatus;
-
   // On RV32 this will only log the low 32 bits, so make sure we're
   // not modifying anything in the upper 32 bits.
   assert((adj_write_mask & 0xffffffffU) == adj_write_mask);