From 993a00a986d0795a3cbb7a2dd0c640d8e6d66734 Mon Sep 17 00:00:00 2001
From: Nick Clifton <nickc@redhat.com>
Date: Tue, 29 Oct 2019 10:01:27 +0000
Subject: [PATCH] Prevent a left shift by a negative value when disassembling
 IA64 binaries.

	* ia64-opc.c (locate_opcode_ent): Prevent a negative shift when
	locating the bit to be tested.
---
 opcodes/ia64-opc.c | 9 ++++++---
 1 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/opcodes/ia64-opc.c b/opcodes/ia64-opc.c
index 5aa1198..ba60f8a 100644
--- a/opcodes/ia64-opc.c
+++ b/opcodes/ia64-opc.c
@@ -372,13 +372,16 @@ locate_opcode_ent (ia64_insn opcode, enum ia64_insn_type type)
 
       bitpos[currstatenum] = currbitnum;
 
-      /* Skip opval[0] bits in the instruction. */
+      /* Skip opval[0] bits in the instruction.  */
       if (op & 0x40)
 	{
 	  currbitnum -= opval[0];
 	}
 
-      /* The value of the current bit being tested. */
+      if (currbitnum < 0)
+	currbitnum = 0;
+
+      /* The value of the current bit being tested.  */
       currbit = opcode & (((ia64_insn) 1) << currbitnum) ? 1 : 0;
       next_op = -1;
 
@@ -463,7 +466,7 @@ locate_opcode_ent (ia64_insn opcode, enum ia64_insn_type type)
 
 	  if (next_op > 65535)
 	    {
-	      abort ();
+	      return -1;
 	    }
 
 	  /* Run through the list of opcodes to check, trying to find
-- 
2.9.3

