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From: Lawrence D'Oliveiro <ldo@nz.invalid>
Newsgroups: comp.arch
Subject: Re: a bit of history, Stealing a Great Idea from the 6600
Date: Sun, 28 Jul 2024 01:45:14 -0000 (UTC)
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On Sat, 4 May 2024 10:08:57 -0000 (UTC), Thomas Koenig wrote:

> Just think of doing a unsigned loop with a lower bound that, due to some
> error in the code or input, has an upper bound of 0-1...

Using the entire range of an unsigned integer type takes some care, but 
can be done:

    unsigned int i;
    bool found;
    ...
  /* length of s might be anything up to largest unsigned integer */
    for (i = len(s);;)
      {
        if (i == 0)
          {
            found = false;
            break;
          } /*if*/
        --i;
        if (matches(s[i]))
          {
            found = true;
            break
          } /*if*/
      } /*for*/
  /* at this point, i will point to the matching element if found */