disas/arm: Avoid unintended sign extension
commit43c227f9dd7945bb4a895f841ecdb957bd8a12da
authorPeter Maydell <peter.maydell@linaro.org>
Fri, 3 Mar 2017 15:50:33 +0000 (3 15:50 +0000)
committerPeter Maydell <peter.maydell@linaro.org>
Tue, 7 Mar 2017 14:33:51 +0000 (7 14:33 +0000)
tree7d0b763a64df2d45bcf95ca28a7d434de63a2229
parent001ebaca7b1120233e04c38f3e3ad3f377137c69
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: Peter Maydell <peter.maydell@linaro.org>
Message-id: 1488556233-31246-7-git-send-email-peter.maydell@linaro.org
disas/arm.c