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Re: [patch 1/4] change specific int128 -> generic intN

On 07/03/2014 06:12 PM, DJ Delorie wrote:
The hardware transfers data in and out of byte-oriented memory in
TYPE_SIZE_UNITS chunks.  Once in a hardware register, all operations
are either 8, 16, or 20 bits (TYPE_SIZE) in size.  So yes, values are
padded in memory, but no, they are not padded in registers.

Setting TYPE_PRECISION is mostly useless, because most of gcc assumes
it's the same as TYPE_SIZE and ignores it.

That's what'll need fixing then. I doubt there are too many places that require changing.

Also, the above seems inaccurate:
$ grep  TYPE_PREC *.c|wc -l
$ grep  TYPE_SIZE *.c|wc -l

 Heck, most of gcc is
oblivious to the idea that types might not be powers-of-two in size.
GCC doesn't even bother with a DECL_PRECISION.

Sure - why would you even need one?

Thus, in these cases, TYPE_SIZE and TYPE_SIZE_UNIT no longer have
a "* BITS_PER_UNIT" mathematical relationship.

I'm skeptical this can work, it's pretty fundamental.

It seems to work just fine in testing, and I'm trying to make it

I also think this is not a very good idea.


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