[Oberon] FPGA - Bit reversal

[Skulski, Wojciech]

Evil?

If you want to manipulate bits, then you cannot escape the fact, they they have their positions within the word. The position depends on a platform. There is no such thing in the world like a computer which would not depend on bit positions. A processor status or setup depends on particular bits within registers, the video or audio depends on particular bits, and so on.

I see this discussion as yet another chasm between computer scientists and engineers. The former want to live in an ideal programming world where algorithms move from place to place without changing anything. For them, bit positions are ugly details to get forgotten. For an engineer the very notion that particular bits are not accessible is a sheer absurd.

I build and program hardware. I deal with bits every day. Anything what hampers my access to bits is an instant enemy. Our friends computer scientists should one day wake up to the fact that hardware has to be controlled by accessing particular bits in particular places. Having good tools for doing this is essential. These tools need to be nurtured rather than frown upon.

I know that Chris is on our side. He programs microcontrollers.  I am talking to the others who still think that Oberon only runs on a Turing machine. Or on Windows.

Thanks,
W
________________________________________
From: Oberon [oberon-bounces at lists.inf.ethz.ch] on behalf of Jörg [joerg.straube at iaeth.ch]
Sent: Saturday, September 23, 2017 9:03 AM
To: chris at cfbsoftware.com; ETH Oberon and related systems
Subject: Re: [Oberon] FPGA - Bit reversal

Chris

I know. ORD() is ‚evil‘ as I wrote in a previous mail. ORD(“S“) is not defined either....

Jörg

Am 23.09.2017 um 14:09 schrieb Chris Burrows <chris at cfbsoftware.com>:

>> -----Original Message-----
>> From: Oberon [mailto:oberon-bounces at lists.inf.ethz.ch] On Behalf Of
>> Jörg
>> Sent: Saturday, 23 September 2017 4:29 PM
>> To: ETH Oberon and related systems
>> Subject: Re: [Oberon] FPGA - Bit reversal
>>
>> No, I disagree.
>> So far Oberon isn t bothered with endianess.
>>
>
> I'm not so sure ...
>
> VAR
>  s: SET;
>  i: INTEGER;
>
> s := {1,2,3);
> i := ORD(s);
>
> What is the value of i?
>
> --
> Chris
>
>
>
> --
> Oberon at lists.inf.ethz.ch mailing list for ETH Oberon and related systems
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