[fpc-devel] OO rewrite - technical questions
pascaldragon at googlemail.com
Mon Jul 26 11:41:32 CEST 2010
Am 26.07.2010 11:22, schrieb Michael Schnell:
> Maybe Win64 uses some "Selector" mechanism (similar as ) so that there
> are no different Selector-Register values in different threads.
Win64 uses GS instead of FS for the TEB and everything else stays the
same. In fact FS and GS (and to some extend CS) are the only selectors
actively used by the x86_64 platform, but - if I understand that
correctly - they can only be set up from ring 0 code (thus: kernel
code), which normally happens during context switches so that the data
of the current thread's TEB is available again.
The usage of the FS and GS selectors in 64bit is also described in AMD's
manual: e.g http://support.amd.com/us/Processor_TechDocs/24592.pdf 2.1.2
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