target/hexagon: handle .new values

Signed-off-by: Brian Cain <[email protected]>

target/hexagon/hex_common.py

@@ -349,6 +349,12 @@ def helper_arg(self):
             self.reg_tcg(),
             f"{self.helper_arg_type()} {self.helper_arg_name()}"
         )
+    def from_subtype(self, subtype):
+        if subtype == "":
+            return self
+        raise Exception(
+            f"unknown subtype '{subtype}' on generic Register class")
+
 
 #
 # Every register is either Single or Pair or Hvx
@@ -1070,11 +1076,22 @@ def init_registers():
     for reg in new_regs:
         new_registers[f"{reg.regtype}{reg.regid}"] = reg
 
-def get_register(tag, regtype, regid):
-    if f"{regtype}{regid}V" in semdict[tag]:
-        return registers[f"{regtype}{regid}"]
-    else:
-        return new_registers[f"{regtype}{regid}"]
+def is_new_reg(tag, regid):
+    if regid[0] in "NO":
+        return True
+    return regid[0] == "P" and \
+           f"{regid}N" in semdict[tag] and \
+           f"{regid}V" not in semdict[tag]
+
+def get_register(tag, regtype, regid, subtype=""):
+    regid = f"{regtype}{regid}"
+    is_new = is_new_reg(tag, regid)
+    try:
+        reg = new_registers[regid] if is_new else registers[regid]
+    except KeyError:
+        raise Exception(f"Unknown {'new ' if is_new else ''}register {regid}" +\
+                        f"from '{tag}' with syntax '{semdict[tag]}'") from None
+    return reg.from_subtype(subtype)
 
 def helper_ret_type(tag, regs):
     ## If there is a scalar result, it is the return type