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disas/microblaze: Avoid unintended sign extension 

In read_insn_microblaze() we assemble 4 bytes into an 'unsigned
long'.  If 'unsigned long' is 64 bits and the high byte has its top
bit set, then C's implicit conversion from 'unsigned char' to 'int'
for the shift will result in an unintended sign extension which sets
the top 32 bits in 'inst'.  Add casts to prevent this.  (Spotted by
Coverity, CID 1005401.)

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Message-id: 1488556233-31246-5-git-send-email-peter.maydell@linaro.org
This commit is contained in:
Peter Maydell 2017-03-03 15:50:31 +00:00
parent 2e3883d03d
commit 1d153a3388
1 changed files with 4 additions and 2 deletions
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6
disas/microblaze.c
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@ -748,9 +748,11 @@ read_insn_microblaze (bfd_vma memaddr,
}
if (info->endian == BFD_ENDIAN_BIG)
inst = (ibytes[0] << 24) | (ibytes[1] << 16) | (ibytes[2] << 8) | ibytes[3];
inst = ((unsigned)ibytes[0] << 24) | (ibytes[1] << 16)
| (ibytes[2] << 8) | ibytes[3];
else if (info->endian == BFD_ENDIAN_LITTLE)
inst = (ibytes[3] << 24) | (ibytes[2] << 16) | (ibytes[1] << 8) | ibytes[0];
inst = ((unsigned)ibytes[3] << 24) | (ibytes[2] << 16)
| (ibytes[1] << 8) | ibytes[0];
else
abort ();