[Oberon] Fw: FPGA - Bitmaps.Mod

[Tomas Kral]

Hi Joerg,

Having also another thought of Bitmaps implementation.
Since a bitmap might have some file disk representation in the end, I am
thinking to have it implemented similarly as Texts(Viewers), where 1024
byte disk sectors `Files.Mod' are mapped through linked list text
descriptors. So in theory only one sector can be displayed through a
viewer at a time.

When I quickly look at PO.V5 source, Kernel.New is used exactly once.

pi at raspberrypi /usr/src/oberon/PO.V5.1 $ grep Kernel.New *.Mod.txt
System.Mod.txt:    IF w = 0 THEN Kernel.New(a, b)

So I do not feel easy breaking this rule, making it a precedence for
more frequent use.

On the analogy, I could have Bitmaps -> BitmapDescr(PictureDescr) ->
PictureFrames

I am not at all sure if it is a good idea?

Tomas  

On Fri, 7 Apr 2017 14:10:31 +0200
Jörg <joerg.straube at iaeth.ch> wrote:

> No.
> 
> The first parameter is declared VAR, so the address of "b.base" is
> handed over. The second parameter shall be a pointer to a type tag.
> The size of a type is stored at offset 0 of the type tag.
> 
> Kernel.New expects the parameter "tag" to be a pointer to type tag.
> SYSTEM.ADR(b.size) is interpreted as a pointer to a type tag.
> 
> The code I was providing is not something a beginner in Oberon should
> use! 1) It's dirty pointer hacking, something that normally C is
> famous for :-) 2) it's very low level, as it bases on internals of
> the implementation of the Oberon memory management.
> 
> But there are typos in my code
> - Firstly, you have to IMPORT SYSTEM as well.
> - Secondly, we have to compare "b.base" to 0 iso NIL, as "b.base" is
> not a pointer.
> 
> br
> Jörg
> 
>  -----Original Message-----
> From: Oberon [mailto:oberon-bounces at lists.inf.ethz.ch] On Behalf Of
> Tomas Kral Sent: Freitag, 7. April 2017 12:55
> To: oberon at lists.inf.ethz.ch
> Subject: Re: [Oberon] Fw: FPGA - Bitmaps.Mod
> 
> Hi Joerg,
> 
> Should it not be coded rather like this?
> Kernel.New(SYSTEM.ADR(b.base), b.size);
> 
> On Fri, 7 Apr 2017 11:43:45 +0200
> Jörg <joerg.straube at iaeth.ch> wrote:
> 
> > Kernel.New(b.base, SYSTEM.ADR(b.size));
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