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Re: [PATCH] Remove all traces of reg_char.
From: Roland McGrath <roland@hack.frob.com>
Date: Thu, 19 Apr 2012 09:23:07 -0700 (PDT)
> The {u,}int_fastN_t types can be used in data structures as well as for
> variables. Also, they are required to be at least as large as intN_t but
> may be larger, whereas intN_t are exact types so you know exactly how
> overflow works and so forth. So the intent is that on machines where
> e.g. subword memory access is much more expensive than full-word access,
> the fastN types might all be no smaller than a word.
This just confirms my suspicions, in that they are for fantasy cpus
that do not exist in nature.
Alpha was the last major cpu to have these sub-word access issues
and even they corrected it in the end.
Therefore these "fast" types really are completely pointless.