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Re: BITS_PER_UNIT larger than 8 -- word addressing
Joseph S. Myers wrote:
On Mon, 26 Nov 2007, Michael Eager wrote:
Well, can't do that. This is not target dependent.
DImode gets defined, and used, for long long in unwind-dw2.c.
Is it defined what DWARF unwind information looks like when made up of
bytes wider than 8 bits? Certainly GCC's code won't allow for it at
present.
I expect that the unwind code is broken unless long long is 8 bytes.
IIRC, unwind confuses host and target integer sizes.
The string handling code is a major area which doesn't allow for target
and host bytes being different. But everything target-independent
hardcoding integer modes wider than QImode is potentially wrong; with wide
bytes, many of those modes may not exist.
IMO, it looks like the absence of a supported 32-bit word-addressed
target let the support for BITS_PER_UNIT != 8 fall into disrepair.
I think that there is a pervasive understanding that SImode is
single precision integer, 32-bits long.
--
Michael Eager eager@eagercon.com
1960 Park Blvd., Palo Alto, CA 94306 650-325-8077