Commit 43c227f9 authored by Peter Maydell's avatar Peter Maydell
Browse files

disas/arm: Avoid unintended sign extension 



When assembling 'given' from the instruction bytes, C's integer
promotion rules mean we may promote an unsigned char to a signed
integer before shifting it, and then sign extend to a 64-bit long,
which can set the high bits of the long.  The code doesn't in fact
care about the high bits if the long is 64 bits, but this is
surprising, so don't do it.

(Spotted by Coverity, CID 1005404.)

Signed-off-by: default avatarPeter Maydell <peter.maydell@linaro.org>
Message-id: 1488556233-31246-7-git-send-email-peter.maydell@linaro.org
parent 001ebaca

disas/arm.c

+2 −2
Original line number Diff line number Diff line
@@ -3901,9 +3901,9 @@ print_insn_arm (bfd_vma pc, struct disassemble_info *info) 


      status = info->read_memory_func (pc, (bfd_byte *)b, 4, info);

      if (little)

	given = (b[0]) | (b[1] << 8) | (b[2] << 16) | (b[3] << 24);

	given = (b[0]) | (b[1] << 8) | (b[2] << 16) | ((unsigned)b[3] << 24);

      else

	given = (b[3]) | (b[2] << 8) | (b[1] << 16) | (b[0] << 24);

	given = (b[3]) | (b[2] << 8) | (b[1] << 16) | ((unsigned)b[0] << 24);

    }

  else

    {