From c5229c3f5f4b6404977bb4134f1a0bda5207ff90 Mon Sep 17 00:00:00 2001
From: Ved Shanbhogue <ved@rivosinc.com>
Date: Sat, 4 May 2024 15:30:10 -0500
Subject: Add Zawrs extension

---
 disasm/disasm.cc      |  5 +++++
 disasm/isa_parser.cc  | 10 ++++++++--
 riscv/insns/wrs_nto.h |  6 ++++++
 riscv/insns/wrs_sto.h |  1 +
 riscv/isa_parser.h    |  1 +
 riscv/riscv.mk.in     |  5 +++++
 6 files changed, 26 insertions(+), 2 deletions(-)
 create mode 100644 riscv/insns/wrs_nto.h
 create mode 100644 riscv/insns/wrs_sto.h

diff --git a/disasm/disasm.cc b/disasm/disasm.cc
index 6716e5b..7c07ec3 100644
--- a/disasm/disasm.cc
+++ b/disasm/disasm.cc
@@ -880,6 +880,11 @@ void disassembler_t::add_instructions(const isa_parser_t* isa)
     DEFINE_XAMO(amocas_h)
   }
 
+  if (isa->extension_enabled(EXT_ZAWRS)) {
+    DEFINE_NOARG(wrs_sto);
+    DEFINE_NOARG(wrs_nto);
+  }
+
   if (isa->extension_enabled(EXT_ZICFILP)) {
     // lpad encodes as `auipc x0, label`, so it needs to be added before auipc
     // for higher disassembling priority
diff --git a/disasm/isa_parser.cc b/disasm/isa_parser.cc
index c0869f3..ee57a51 100644
--- a/disasm/isa_parser.cc
+++ b/disasm/isa_parser.cc
@@ -123,6 +123,8 @@ isa_parser_t::isa_parser_t(const char* str, const char *priv)
       extension_table[EXT_ZACAS] = true;
     } else if (ext_str == "zabha") {
       extension_table[EXT_ZABHA] = true;
+    } else if (ext_str == "zawrs") {
+      extension_table[EXT_ZAWRS] = true;
     } else if (ext_str == "zmmul") {
       extension_table[EXT_ZMMUL] = true;
     } else if (ext_str == "zba") {
@@ -378,14 +380,18 @@ isa_parser_t::isa_parser_t(const char* str, const char *priv)
     bad_isa_string(str, "'Zcf/Zcd/Zcb/Zcmp/Zcmt' extensions require 'Zca' extension");
   }
 
-  if (extension_table[EXT_ZACAS] && !extension_table['A'] && !extension_table[EXT_ZAAMO]) {
+  if (extension_table[EXT_ZACAS] && !extension_table[EXT_ZAAMO]) {
     bad_isa_string(str, "'Zacas' extension requires either the 'A' or the 'Zaamo' extension");
   }
 
-  if (extension_table[EXT_ZABHA] && !extension_table['A'] && !extension_table[EXT_ZAAMO]) {
+  if (extension_table[EXT_ZABHA] && !extension_table[EXT_ZAAMO]) {
     bad_isa_string(str, "'Zabha' extension requires either the 'A' or the 'Zaamo' extension");
   }
 
+  if (extension_table[EXT_ZAWRS] && !extension_table[EXT_ZALRSC]) {
+    bad_isa_string(str, "'Zabha' extension requires either the 'A' or the 'Zalrsc' extension");
+  }
+
   // When SSE is 0, Zicfiss behavior is defined by Zicmop
   if (extension_table[EXT_ZICFISS] && !extension_table[EXT_ZIMOP]) {
     bad_isa_string(str, "'Zicfiss' extension requires 'Zimop' extension");
diff --git a/riscv/insns/wrs_nto.h b/riscv/insns/wrs_nto.h
new file mode 100644
index 0000000..710e670
--- /dev/null
+++ b/riscv/insns/wrs_nto.h
@@ -0,0 +1,6 @@
+if (get_field(STATE.mstatus->read(), MSTATUS_TW)) {
+  require_privilege(PRV_M);
+} else if (STATE.v) {
+  if (get_field(STATE.hstatus->read(), HSTATUS_VTW))
+    require_novirt();
+}
diff --git a/riscv/insns/wrs_sto.h b/riscv/insns/wrs_sto.h
new file mode 100644
index 0000000..4e71aa0
--- /dev/null
+++ b/riscv/insns/wrs_sto.h
@@ -0,0 +1 @@
+// WRS.STO stalls for a short duration
diff --git a/riscv/isa_parser.h b/riscv/isa_parser.h
index 4bd9d4b..65c34fd 100644
--- a/riscv/isa_parser.h
+++ b/riscv/isa_parser.h
@@ -68,6 +68,7 @@ typedef enum {
   EXT_ZALRSC,
   EXT_ZACAS,
   EXT_ZABHA,
+  EXT_ZAWRS,
   EXT_INTERNAL_ZFH_MOVE,
   EXT_SMCSRIND,
   EXT_SSCSRIND,
diff --git a/riscv/riscv.mk.in b/riscv/riscv.mk.in
index 6db6fa9..469c48d 100644
--- a/riscv/riscv.mk.in
+++ b/riscv/riscv.mk.in
@@ -987,6 +987,10 @@ riscv_insn_ext_zabha = \
 	amoxor_h \
 	amocas_h \
 
+riscv_insn_ext_zawrs = \
+	wrs_sto \
+	wrs_nto \
+
 riscv_insn_ext_zalasr = \
 	lb_aq \
 	lh_aq \
@@ -1099,6 +1103,7 @@ riscv_insn_list = \
 	$(riscv_insn_ext_q_zfa) \
 	$(riscv_insn_ext_zacas) \
 	$(riscv_insn_ext_zabha) \
+	$(riscv_insn_ext_zawrs) \
 	$(riscv_insn_ext_zalasr) \
 	$(riscv_insn_ext_zce) \
 	$(riscv_insn_ext_zfh) \
-- 
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