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Variable sizes and efficiency...


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One other only tangentially oskit-related question, if I might gather
an expert opinion...

For simplicity of access for the user, I was planning to use separate
process IDs (unique across the system), and thread IDs (unique across
an individual process), so that the exception-handling thread of a
given process would always be 0 and the working threads 1 and
up. Then, to generate a system-wide unique thread-id for internal
kernel use, I'd simply concatenate the two together, something like:

typedef union utid_u
{
  longtype utid ;
  struct
  {
    shorttype pid ;
    shorttype tid ;
  } pt ;
} utid ;

Now, I'm developing on the x86, of course, on which I've heard that
the (16-bit) short is a most horribly inefficient size to use; but the
(64-bit) long long (gcc) presumably isn't all that much better and
could well be worse.

If I go along with this model, does anyone have any pressing reason
why I should go along with two longs making a longlong, as opposed to
two shorts making a long? I'm more inclined towards the former at
present, but...

Thanks,

Alistair

- -- 
Computational Thaumaturge, Deus Machinarum. -- Cerebrate of the Silicon Swarm.
e-mail: avatar-sig@arkane.demon.co.uk      WWW: http://www.arkane.demon.co.uk/
"I prefer to think of 'fax' as a shortening of 'fac simile sed longe', a Latin
 command meaning, 'make it the same, only far away.'" -- Ed Hopkins

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