[Bug 19982] SetThreadAffinityMask() seems not to work correctly

[wine-bugs at winehq.org]

http://bugs.winehq.org/show_bug.cgi?id=19982





--- Comment #32 from ray at pobox.co.uk  2009-09-30 15:53:18 ---
(In reply to comment #22)
I have also just spotted another very obscure bug:

proc_affinity = (1 << si.dwNumberOfProcessors) - 1;

This will typically generate:

00474CBD   push        1
00474CBF   pop         eax
00474CC0   mov         ecx,esi
00474CC2   shl         eax,cl
00474CC4   dec         eax

which for the case of 32 CPUs the after the shl eax,cl EAX will still contain 1
!

If you look in http://www.intel.com/Assets/PDF/manual/253667.pdf you will find:

IA-32 Architecture Compatibility
The 8086 does not mask the shift count. However, all other IA-32 processors
(starting with the Intel 286 processor) do mask the shift count to 5 bits,
resulting in a maximum count of 31. This masking is done in all operating modes
(including the virtual-8086 mode) to reduce the maximum execution time of the
instructions.

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