Re: Doubts about Segmentation

robertwessel2@xxxxxxxxx schrieb:
ArarghMail604NOSPAM@xxxxxxxxxxxxxxxxx wrote:

On Wed, 26 Apr 2006 14:26:41 +0400, "Maxim S. Shatskih"
<maxim@xxxxxxxxxxxxxxxx> wrote:

<snip>

In MS-DOS, the MZ format is not such. The whole binary (all segments) is one
large BLOB loaded once and never discarded. There is also the relocation
table - a list of locations within the BLOB where the base address of the load
must be added.

Not always, you could create demand loaded overlays, AFAIK.

Well, not really. MZ had no provision for such, but a number of folks
created overlay linkers which allowed the overlays to be attached to
the end of the MZ (which was what the OS loaded), but they were never
really part of it. The overlay linker would add code to your program
to load and manage the overlays, it was never an OS function.

RBIL->Inter61b.zip->Interrup.g

INT 21 - DOS 2+ - "EXEC" - LOAD AND/OR EXECUTE PROGRAM
AH = 4Bh
AL = type of load
03h load overlay

Offset Size Description (Table 01591)
00h WORD segment at which to load overlay
02h WORD relocation factor to apply to overlay if in .EXE format

....but i never test it.

Dirk
.

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