[fpc-pascal](no subject)

Tobias Hermann tobih at mayn.de
Sun Dec 3 01:46:03 CET 2000

So in 32 bit architecture a pointer is only a 32 bit offset, isn't it?
Adressed from 0 to XXXX Bytes...

But how does the OS and the CPU handle the "protected" memory blocks? In 16
bit with selectors, the selectors were a value to an table that stored data
of the blocks, how they were protected, if its a code segment or a data
segment, etc. etc.
how is this done in 32 bit?

Or have I misunderstood something?


----- Original Message -----
From: Kuba Ober <winnie at hoth.amu.edu.pl>
To: <fpc-pascal at deadlock.et.tudelft.nl>
Sent: Saturday, December 02, 2000 10:59 PM
Subject: Re: [fpc-pascal](no subject)

> The pointer is offset and selector taken together. An offset by itself
> nothing, a selector by itself means nothing as well. A selector is used to
> give the offset a meaning, and only together shall they be used, for
> no use when they are 'part, only sigsegv :-)
> Take that l-i-t-e-r-a-l-l-y if you don't otherwise want to delve into i386
> specs. Selectors are 16 bit only on all architectures which use selectors,
> there is hardly need for more than 65535 selectors. Offsets are 32 bit on
> bit machines.
> Kuba

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