[Oberon] FPGA - Bitmaps.Mod

Skulski, Wojciech skulski at pas.rochester.edu
Wed Apr 5 14:16:29 CEST 2017

> I am looking for a better way, as I believe the size needed can be
> calculated from Width, Height of the bitmap.

Yes. The size of the display should not be fixed with inline numbers. I am thinking that a usable System can be deployed with 800x600 display. In general, the size of the display can/ should be changed either on the fly or during compilation, which probably is not very difficult to implement in a simple design which the FPGA Oberon really is.

From: Oberon [oberon-bounces at lists.inf.ethz.ch] on behalf of Tomas Kral [thomas.kral at email.cz]
Sent: Wednesday, April 5, 2017 5:26 AM
To: Oberon at lists.inf.ethz.ch
Subject: [Oberon] FPGA - Bitmaps.Mod


As part of my exercise I have converted ETH `Bitmaps.Mod' to V07. It
should be the basis for a bit map editor - `Paint.Mod' - next exercise
of mine.

It is far from perfect, just made it to compile under V07, without
much thoughts.

Few notes>>>

[a] Bitmaps.DisplayBlock* is just copied from Display.CopyBlock*
with source and destination addresses modified as thus:

sa := B.address + u0*4 + sy*128; da := Display.Base + v0*4 + dy*128;

I am looking for a better idea, as I believe bitmap needs to be clipped
to fit into a visible area of a target frame.

[b] New bitmap is allocated as a constant buffer
  BufSize = 10000H;
END Bitmaps.

I am looking for a better way, as I believe the size needed can be
calculated from Width, Height of the bitmap.

  Bitmap* = POINTER TO BitmapDesc;
  BitmapDesc* = RECORD  (* cf. Display.DisplayBlock  *)
    width*, height*, depth*: INTEGER;  (* offset 0, 2, 4 *)
    wth*, address*: LONGINT;  (* offset 8, 12 *)
    size: LONGINT

[c] Bitmaps are allocated as an array of CHAR's. Is it a good idea to
use BYTE's instead?

P.S. I could enclose the whole module, but I am not sure if it is
allowed by the list server.

Many thanks
Oberon at lists.inf.ethz.ch mailing list for ETH Oberon and related systems

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