[fpc-pascal](no subject)

[Carlo Kok]

----- Original Message -----
From: "Tobias Hermann" <tobih at mayn.de>
To: <fpc-pascal at deadlock.et.tudelft.nl>
Sent: Sunday, December 03, 2000 1:46 AM
Subject: Re: [fpc-pascal](no subject)


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

Yes.

>
> 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?

The DPMI host handles all the memory tables and where wat is stored. This is
not of a Free Pascal programmers concern. You can use GetMem, FreeMem,
Reallocmen, New, Dispose etc for creating and removing variables. If you
really want to know how this is done, you should have a look at the linux
source.

>
> Or have I misunderstood something?
>
> Tobi
>
> ----- 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
> means
> > 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
> there's
> > 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,
> as
> > there is hardly need for more than 65535 selectors. Offsets are 32 bit
on
> 32
> > bit machines.
> >
> > Kuba
>
>
>
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