[U-Boot] hi, I could not understand the memsize.c, somebody help me?

Detlev Zundel dzu at denx.de
Thu Jun 25 14:56:49 CEST 2009


Hi ya,

> I could not understand common/memsize.c, how it works?

Like a charm ;)

> maxsize / sizeof (long), what's meaning of it? why sizeof (long) is
> dividend?

As the comment in line 50 states, "cnt" is used in pointer arithmetic,
so addr is increased in sizeof(long) bytes.  maxsize however is
considered to be in bytes only.  Makes sense?

> just like stack,  push every step mem addr to save:
>
> save[i++] = *addr;
> and then?

Cannot parse the question.  

The algorithm should be pretty clear however (take a paper and pencil
and work out the values of addr as it proceeds) - we save the original
content of the adressed cells and write our own pattern there (~cnt).
Then we walk these cells upward and see where the previous write did not
work like it was supposed to - voila.

Cheers
  Detlev

-- 
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