Re: [Flashforth-devel] For-next loops - the New Design

[om1zz <om...@vo...>]

Peter,

for people coming from high-level languages there will be ?for-next.

0 for-next may loop 65536 times, because the do-loop does the same (and it is therefore consistent),
You may try (in FF btw.):

: mytest do i u. loop ;
0 0 mytest

what you will see? This:

0 0 mytest 0 1 2 3 4 5 6 7 8...
65533 65534 65535  ok<#,ram>

It loops 65536 times (2^16). That is normal in forth.

Forth is not a high-level language, that has to be explained to the people coming from high-level area..

Igor

______________________________________________________________
> Od: Peter Jacobs <pe...@me...>
> Komu: <fla...@li...>
> Datum: 28.05.2015 13:27
> Předmět: Re: [Flashforth-devel] For-next loops - the New Design
>
>Igor,
>    I'm going to disagree with you on preference.  I think that most 
>people will come to FF, not from assembler, but from some other 
>high-level language and they will expect "0 for" to iterate 0 times.  I 
>know that I do.  If I wanted to iterate 65536 times in one of my 
>programs, I'd likely be wanting to do more iterations at some point and 
>I'd use a 24-bit or 32-bit counter anyway.
>Regards,
>Peter J.
>
>
>On 28/05/15 21:03, om1zz wrote:
>> Do you insist on a single asm instruction for the entire for-next loop implementation?
>> Do-loop is min 30 instructions in FF.
>>
>> I think that with N vs. N+1 idea when handling for (in any form) you break the consistency of for-loop implementation understanding.
>>
>> I would easily spend another 1-2 asm instructions and do it consistent. Speed plays no role here.
>> When somebody wants to bitbang a pin it could be done in asm.
>>
>> N for ..
>> N ?for ..
>>
>> both will do N loops through the body. The only diff is the ?for skips zero. That is very consistent.
>>
>> 0 for
>>
>> will do M loops where M=2^16 in this case. That is also consistent as you work with 16bit assembler.
>>
>> I am suggesting that as a standard for the for-loop design for any architecture on my github.
>>
>> Igor.
>>
>>
>>
>>
>> ______________________________________________________________
>>> Od: Mikael Nordman <mik...@fl...>
>>> Komu: <fla...@li...>
>>> Datum: 27.05.2015 17:59
>>> Předmět: Re: [Flashforth-devel] For-next loops - the New Design
>>>
>>> Yes, Yes,
>>> I understand what you want.
>>> But you dont seem to understand that it cannot be done
>>> in a simple for..next loop that has only one decrement and branch
>>> instruction, and that has an index that counts down to zero.
>>>
>>> In order the get the full 16 bit loop count you have to give as input
>>> the N+1 count.
>>>
>>> But if you have some idea how to implement it in PIC assembly code,
>>> please write it out.
>>>
>>> BR Mike
>>>
>>> On 27.05.2015 10:32, om1zz wrote:
>>>> 0 _for 65535 65534 ..
>>>> .. 13 12 11 10 9 8 7 6 5 4 3 2 1 0
>>>> 65536 ok<#,ram>
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