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Re: [COMMITTED] tilegx: enable wordsize-64 support for ieee745 dbl-64.
- From: Joseph Myers <joseph at codesourcery dot com>
- To: Chris Metcalf <cmetcalf at ezchip dot com>
- Cc: <libc-alpha at sourceware dot org>
- Date: Tue, 23 Dec 2014 20:06:17 +0000
- Subject: Re: [COMMITTED] tilegx: enable wordsize-64 support for ieee745 dbl-64.
- Authentication-results: sourceware.org; auth=none
- References: <201412231905 dot sBNJ5c3C004622 at farm-0002 dot internal dot tilera dot com>
On Tue, 23 Dec 2014, Chris Metcalf wrote:
> I missed this during the initial port. Some testing shows that
> enabling this mode does, unsurprisingly, yield some nice speedups
> on the math functions in question.
I take it that the ABI on tilegx32 allows the lround alias to llround
(that is, the upper 32 bits of a return value are unspecified, so that
when an out-of-range value is passed in the return value always acts
consistently like some value of type long rather than causing undefined
behavior in the caller as it would if the ABI requires sign extension or
zero extension but the result isn't properly extended)? (That alias
wouldn't be valid on MIPS n32, as all 32-bit values have to be
sign-extended in registers - it's architecturally undefined how 32-bit
instructions behave on 64-bit MIPS when given registers that aren't
Joseph S. Myers