[Qemu-devel] [Bug 591320] [NEW] [ARM]: SIMD add/sub instructions are incorrect

[Bradley Smith]

Public bug reported:

The thumb2 and unsigned arm state SIMD add/sub instructions are
implemented incorrectly, for example:

  UQSUB8 r0, r1, r0

gives r0 as 0,  where r0 is 0x12345678 and r1 is 0x23456789 in ARM
state, and:

  UHSUB8 r0, r1, r0

gives r0 as 0x1111be01, where r0 is 0x12345678 and r1 is 0x23456789 in
thumb2 state.

This problem is present in git HEAD, (at time of writing,
fd1dc858370d9a9ac7ea2512812c3a152ee6484b).

** Affects: qemu
     Importance: Undecided
         Status: New

-- 
[ARM]: SIMD add/sub instructions are incorrect
https://bugs.launchpad.net/bugs/591320
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Status in QEMU: New

Bug description:
The thumb2 and unsigned arm state SIMD add/sub instructions are implemented 
incorrectly, for example:

  UQSUB8 r0, r1, r0

gives r0 as 0,  where r0 is 0x12345678 and r1 is 0x23456789 in ARM state, and:

  UHSUB8 r0, r1, r0

gives r0 as 0x1111be01, where r0 is 0x12345678 and r1 is 0x23456789 in thumb2 
state.

This problem is present in git HEAD, (at time of writing, 
fd1dc858370d9a9ac7ea2512812c3a152ee6484b).