[PATCH 4/6] S/390: Simplify opcode search loop in disassembler

[Andreas Arnez <arnez at linux dot vnet dot ibm dot com>]

opcodes/
	* s390-dis.c (print_insn_s390): Simplify the opcode search loop.
	Check architecture mask against all searched opcodes, not just the
	first matching one.
---
 opcodes/s390-dis.c | 52 +++++++++++++++++++---------------------------------
 1 file changed, 19 insertions(+), 33 deletions(-)

diff --git a/opcodes/s390-dis.c b/opcodes/s390-dis.c
index e6b0ee5..029f9f1 100644
--- a/opcodes/s390-dis.c
+++ b/opcodes/s390-dis.c
@@ -229,8 +229,7 @@ int
 print_insn_s390 (bfd_vma memaddr, struct disassemble_info *info)
 {
   bfd_byte buffer[6];
-  const struct s390_opcode *opcode;
-  const struct s390_opcode *opcode_end;
+  const struct s390_opcode *opcode = NULL;
   unsigned int value;
   int status, opsize, bufsize;
 
@@ -266,41 +265,28 @@ print_insn_s390 (bfd_vma memaddr, struct disassemble_info *info)
     {
       const struct s390_opcode *op;
 
-      /* Find the first match in the opcode table.  */
-      opcode_end = s390_opcodes + s390_num_opcodes;
-      for (opcode = s390_opcodes + opc_index[(int) buffer[0]];
-	   (opcode < opcode_end) && (buffer[0] == opcode->opcode[0]);
-	   opcode++)
+      /* Find the "best match" in the opcode table.  */
+      for (op = s390_opcodes + opc_index[buffer[0]];
+	   op != s390_opcodes + s390_num_opcodes
+	     && op->opcode[0] == buffer[0];
+	   op++)
 	{
-	  /* Check architecture.  */
-	  if (!(opcode->modes & current_arch_mask))
-	    continue;
-
-	  if (!s390_insn_matches_opcode (buffer, opcode))
-	    continue;
-
-	  /* Advance to an opcode with a more specific mask.  */
-	  for (op = opcode + 1; op < opcode_end; op++)
-	    {
-	      if ((buffer[0] & op->mask[0]) != op->opcode[0])
-		break;
-
-	      if (!s390_insn_matches_opcode (buffer, op))
-		continue;
-
-	      if (opcode_mask_more_specific (op, opcode))
-		opcode = op;
-	    }
-
-	  /* The instruction is valid.  */
-	  s390_print_insn_with_opcode (memaddr, info, buffer, opcode);
-
-	  /* Found instruction, printed it, return its size.  */
-	  return opsize;
+	  if ((op->modes & current_arch_mask)
+	      && s390_insn_matches_opcode (buffer, op)
+	      && (opcode == NULL
+		  || opcode_mask_more_specific (op, opcode)))
+	    opcode = op;
 	}
-      /* No matching instruction found, fall through to hex print.  */
     }
 
+  if (opcode != NULL)
+    {
+      /* The instruction is valid.  Print it and return its size.  */
+      s390_print_insn_with_opcode (memaddr, info, buffer, opcode);
+      return opsize;
+    }
+
+  /* Fall back to hex print.  */
   if (bufsize >= 4)
     {
       value = (unsigned int) buffer[0];
-- 
1.8.4.2