[fpc-pascal]Interrupts under Go32

Thomas Schatzl tom_at_work at yline.com
Fri Aug 17 18:31:54 CEST 2001

----- Original Message -----
From: "Shifted Soul" <snsii at yahoo.fr>
Subject: [fpc-pascal]Interrupts under Go32


> I read the documentation about how to write ISRs in Go32.
> I found this snip of code :
> ------!Cut!-------
> backupDS : Word; external name '___v2prt0_ds_alias';
> ------!Cut!-------
> (In the Standard units reference manual > The Go32 unit > Hardware
> interrupts)
> What is "___v2prt0_ds_alias" ? What kind of value it can have ? in which
> (external object) file it is found ?

The go32v2 environment guarantees that this selector specifies a valid
descriptor to the data segment (or the memory area used as ds in fpc) even
during interrupts, exceptions etc afair.

Don't assume any specific values for it, may be different every time the
program starts up.

It is defined in prt0.s in the rtl source tree (prt0.o).


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