[SLOF] [PATCH v2] fat-files: Fix access to FAT32 dir/files when cluster > 16-bits

[Thomas Huth]

On 09.06.2016 10:21, Segher Boessenkool wrote:
> On Thu, Jun 09, 2016 at 09:35:42AM +0200, Thomas Huth wrote:
>>>  : (find-file) ( -- cluster file-len is-dir? true | false )
>>>    data @ BEGIN dup data @ #data @ + < WHILE
>>>    dup dos-name b comp WHILE 20 + REPEAT
>>> -  dup 1a + 2c@ bwjoin swap dup 1c + 4c@ bljoin swap 0b + c@ 10 and 0<> true
>>> +  dup get-cluster
>>> +  swap dup 1c + 4c@ bljoin swap 0b + c@ 10 and 0<> true
>>>    ELSE drop false THEN ;
>>
>> Unrelated to your patch, but: WTF? Where's the IF-statement for that
>> ELSE? ... must be some magic code by Segher again ... ;-)
> 
> Heh.  Nothing magic, just
> 
> BEGIN ... WHILE ... WHILE ... REPEAT ... ELSE ... THEN
> 
> 1:  BEGIN
>      ...
>     WHILE   \ if 0, goto 3
>      ...
>     WHILE   \ if 0, goto 2
>      ...
>     REPEAT  \ goto 1
> 2:   ...
>     ELSE    \ goto 4
> 3:   ...
>     THEN
> 4:
> 
> so just an indeterminate loop with two exits.

Wow ... and I thought I basically would be able nowadays to understand
most of the Forth code that you wrote ... looks like I was wrong 8-)

Thanks for the explanation!

 Thomas