1 files changed, 38 insertions, 17 deletions

diff --git a/opcodes/s390-dis.c b/opcodes/s390-dis.c
index eeaeaf8..8134073 100644
--- a/opcodes/s390-dis.c
+++ b/opcodes/s390-dis.c
@@ -29,6 +29,7 @@
 static int init_flag = 0;
 static int opc_index[256];
 static int current_arch_mask = 0;
+static int option_use_insn_len_bits_p = 0;
 
 /* Set up index table for first opcode byte.  */
 
@@ -51,6 +52,8 @@ init_disasm (struct disassemble_info *info)
 	current_arch_mask = 1 << S390_OPCODE_ESA;
       else if (CONST_STRNEQ (p, "zarch"))
 	current_arch_mask = 1 << S390_OPCODE_ZARCH;
+      else if (CONST_STRNEQ (p, "insnlength"))
+	option_use_insn_len_bits_p = 1;
       else
 	fprintf (stderr, "Unknown S/390 disassembler option: %s\n", p);
 
@@ -261,7 +264,7 @@ print_insn_s390 (bfd_vma memaddr, struct disassemble_info *info)
   bfd_byte buffer[6];
   const struct s390_opcode *opcode = NULL;
   unsigned int value;
-  int status, opsize, bufsize;
+  int status, opsize, bufsize, bytes_to_dump, i;
 
   if (init_flag == 0)
     init_disasm (info);
@@ -307,38 +310,54 @@ print_insn_s390 (bfd_vma memaddr, struct disassemble_info *info)
 		  || opcode_mask_more_specific (op, opcode)))
 	    opcode = op;
 	}
-    }
 
-  if (opcode != NULL)
-    {
-      /* The instruction is valid.  Print it and return its size.  */
-      s390_print_insn_with_opcode (memaddr, info, buffer, opcode);
-      return opsize;
+      if (opcode != NULL)
+	{
+	  /* The instruction is valid.  Print it and return its size.  */
+	  s390_print_insn_with_opcode (memaddr, info, buffer, opcode);
+	  return opsize;
+	}
     }
 
+  /* For code sections it makes sense to skip unknown instructions
+     according to their length bits.  */
+  if (status == 0
+      && option_use_insn_len_bits_p
+      && info->section != NULL
+      && (info->section->flags & SEC_CODE))
+    bytes_to_dump = opsize;
+  else
+    /* By default unknown instructions are printed as .long's/.short'
+       depending on how many bytes are available.  */
+    bytes_to_dump = bufsize >= 4 ? 4 : bufsize;
+
+  if (bytes_to_dump == 0)
+    return 0;
+
   /* Fall back to hex print.  */
-  if (bufsize >= 4)
+  switch (bytes_to_dump)
     {
+    case 4:
       value = (unsigned int) buffer[0];
       value = (value << 8) + (unsigned int) buffer[1];
       value = (value << 8) + (unsigned int) buffer[2];
       value = (value << 8) + (unsigned int) buffer[3];
       info->fprintf_func (info->stream, ".long\t0x%08x", value);
       return 4;
-    }
-  else if (bufsize >= 2)
-    {
+    case 2:
       value = (unsigned int) buffer[0];
       value = (value << 8) + (unsigned int) buffer[1];
       info->fprintf_func (info->stream, ".short\t0x%04x", value);
       return 2;
+    default:
+      info->fprintf_func (info->stream, ".byte\t0x%02x",
+			  (unsigned int) buffer[0]);
+      for (i = 1; i < bytes_to_dump; i++)
+	info->fprintf_func (info->stream, ",0x%02x",
+			  (unsigned int) buffer[i]);
+      return bytes_to_dump;
     }
-  else
-    {
-      value = (unsigned int) buffer[0];
-      info->fprintf_func (info->stream, ".byte\t0x%02x", value);
-      return 1;
-    }
+  return 0;
 }
 
 void
@@ -350,4 +369,6 @@ with the -M switch (multiple options should be separated by commas):\n"));
 
   fprintf (stream, _("  esa         Disassemble in ESA architecture mode\n"));
   fprintf (stream, _("  zarch       Disassemble in z/Architecture mode\n"));
+  fprintf (stream, _("  insnlength  Print unknown instructions according "
+		     "to length from first two bits\n"));
 }