[Oberon] FPGA - Pictures.Mod

Tomas Kral thomas.kral at email.cz
Mon Sep 25 20:35:35 CEST 2017


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


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,

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

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>

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