[Oberon] FPGA - Pictures.Mod

[Tomas Kral]

Hi,

I have made some progress with Oberon pictures. I am now able to
process `RLE' runs and load pixels into bitmap area. 

https://github.com/tcat-qldom/Oberon-pictures

It is still not clear to me, if colour bitmaps are also RLE-compressed,
as b&w bitmaps compress subsequent pixels of the same colour,
correct?

To formulate `EBNF' for `RLE', may be next exercise of mine, before
writing compress method.

I have coded in assembly, a simplified `RLE' de/compressor for `Sinclair
QL'. `RLE' sequence is identified by two equal short words, as display
buffer is organised by words. One word controls RGB colour of four
pixels.

EDIT, example

QL display buffer is 32768 bytes, entire black screen is compressed
into only three words, 0,0,16384. But with bitmaps of high level
of detail, compression ratio drops.

-- 
Tomas Kral <thomas.kral at email.cz>