diff --git a/disas/arm.c b/disas/arm.c
index 6165246539..7a7354b76a 100644
--- a/disas/arm.c
+++ b/disas/arm.c
@@ -1779,7 +1779,7 @@ print_insn_coprocessor (bfd_vma pc, struct disassemble_info *info, long given,
 
 			/* Is ``imm'' a negative number?  */
 			if (imm & 0x40)
-			  imm |= (-1 << 7);
+			  imm |= (~0u << 7);
 
 			func (stream, "%d", imm);
 		      }