[Oberon] FPGA - SET initialisation

[Jörg]

Hi Tomas

One possibilty is to split your algorithm in three parts
1) handle the left border (max 31 bit) until you reach a multiple of 32 bit
2) then copy n words (32 bit)
3) handle the right border = remaining bits up to the width "w"

Jörg

> Am 30.04.2017 um 16:33 schrieb Tomas Kral <thomas.kral at email.cz>:
> 
> Chris, Joerg,
> 
> Learning, not doing much useful bitmap examples.
> 
> I was surprised to realise, Bitmaps are easy to be copied/displayed,
> by lines, after each line destination address is incremented by 128
> bytes per display line, source address by bitmap width DIV 8, lines h
> decremented by 1.
> 
> This works nicely on any bitmap of widths multiple of
> 32 bits accross. 32xN, 64xN, etc, and must be aligned horizontally also
> on 32 bit as well, for x=0,32,64,.. coordinate (x,y = top left).
> Bitmaps are drawn upwards. 
> 
> (* paints horizontal bitmap line, for x,w=32,64,... *)
> PROCEDURE PaintHLine(src, dst, w: INTEGER);
>  VAR s,t: SET;
> BEGIN
>  w := (w+7) DIV 8; (* bytes per bitmap line *)
>  WHILE w > 0 DO
>    SYSTEM.GET(src, t);  SYSTEM.GET(dst, s);
>    SYSTEM.PUT(dst, s + t);
>    INC(dst, 4);  INC(src, 4);  DEC(w, 4)
>  END
> END PaintHLine;
> 
> I am looking into a solution where x can spill over byte boundary,
> also width of finer bitwise granularity.  
> 
> I did a similar exercise in assembly many, many years ago on 8-bit
> computers.
> 
> Tomas
> 
> 
> On Sun, 30 Apr 2017 21:26:09 +0930
> Chris Burrows <chris at cfbsoftware.com> wrote:
> 
>>> -----Original Message-----
>>> From: Oberon [mailto:oberon-bounces at lists.inf.ethz.ch] On Behalf Of
>>> Tomas Kral
>>> Sent: Sunday, 30 April 2017 8:05 PM
>>> To: oberon at lists.inf.ethz.ch
>>> Subject: Re: [Oberon] FPGA - SET initialisation
>>> 
>>> Ah yes, sily me.
>>> 
>>> But how to best initialise a SET variable with an arbitrary byte /
>>> integer?
>>> 
>>> TYPE ii = POINTER TO iidsc;
>>> iidsc = STRUCT i: INTEGER END;
>>> 
>>> i := b; SYSTEM.PUT(ii,i); SYSTEM.GET(ii,s); (* initialise a set with
>>> a byte *) SYSTEM.PUT(ii,i); SYSTEM.GET(ii,s); (* initialise a set
>>> with an integer
>>> *)
>>> 
>> 
>> Do you mean how do you typecast an INTEGER / BYTE variable to a SET
>> variable?
>> 
>> If so then:
>> 
>>  VAR
>>    s: SET;
>>    i: INTEGER;
>>    b: BYTE;
>> 
>>  BEGIN
>>    s := SYSTEM.VAL(SET, i); 
>>    s := SYSTEM.VAL(SET, ORD(b))
>> 
>> I'm curious. What is it that you are trying to do that makes you ask
>> this question?
>> 
>> Regards,
>> Chris Burrows
>> CFB Software
>> http://www.astrobe.com/RISC5
>> 
>> --
>> Oberon at lists.inf.ethz.ch mailing list for ETH Oberon and related
>> systems https://lists.inf.ethz.ch/mailman/listinfo/oberon
> 
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