aarch64: Commonise index parsing

Just a minor clean-up to factor out the index parsing, partly to
ensure that the error handling remains consistent.  No behavioural
change intended.

diff --git a/gas/config/tc-aarch64.c b/gas/config/tc-aarch64.c
index e5185353013ce2a14438f3835c095347185272ff..dafd5bc296c9ce37832024ce7dbd8d4e84279185 100644 (file)
--- a/gas/config/tc-aarch64.c
+++ b/gas/config/tc-aarch64.c
@@ -1022,6 +1022,23 @@ aarch64_valid_suffix_char_p (aarch64_reg_type type, char ch)
     }
 }
 
+/* Parse an index expression at *STR, storing it in *IMM on success.  */
+
+static bool
+parse_index_expression (char **str, int64_t *imm)
+{
+  expressionS exp;
+
+  aarch64_get_expression (&exp, str, GE_NO_PREFIX, REJECT_ABSENT);
+  if (exp.X_op != O_constant)
+    {
+      first_error (_("constant expression required"));
+      return false;
+    }
+  *imm = exp.X_add_number;
+  return true;
+}
+
 /* Parse a register of the type TYPE.
 
    Return null if the string pointed to by *CCP is not a valid register
@@ -1116,8 +1133,6 @@ parse_typed_reg (char **ccp, aarch64_reg_type type,
 
   if (!(flags & PTR_FULL_REG) && skip_past_char (&str, '['))
     {
-      expressionS exp;
-
       /* Reject Sn[index] syntax.  */
       if (!is_typed_vecreg)
        {
@@ -1133,18 +1148,11 @@ parse_typed_reg (char **ccp, aarch64_reg_type type,
 
       atype.defined |= NTA_HASINDEX;
 
-      aarch64_get_expression (&exp, &str, GE_NO_PREFIX, REJECT_ABSENT);
-
-      if (exp.X_op != O_constant)
-       {
-         first_error (_("constant expression required"));
-         return NULL;
-       }
+      if (!parse_index_expression (&str, &atype.index))
+       return NULL;
 
       if (! skip_past_char (&str, ']'))
        return NULL;
-
-      atype.index = exp.X_add_number;
     }
   else if (!(flags & PTR_IN_REGLIST) && (atype.defined & NTA_HASINDEX) != 0)
     {
@@ -1318,18 +1326,10 @@ parse_vector_reg_list (char **ccp, aarch64_reg_type type,
     {
       if (skip_past_char (&str, '['))
        {
-         expressionS exp;
-
-         aarch64_get_expression (&exp, &str, GE_NO_PREFIX, REJECT_ABSENT);
-         if (exp.X_op != O_constant)
-           {
-             set_first_syntax_error (_("constant expression required."));
-             error = true;
-           }
+         if (!parse_index_expression (&str, &typeinfo_first.index))
+           error = true;
          if (! skip_past_char (&str, ']'))
            error = true;
-         else
-           typeinfo_first.index = exp.X_add_number;
        }
       else
        {