soft-fp: add macro FP_NO_EXCEPTIONS

[Joseph S. Myers]

On Tue, 15 Oct 2013, Richard Henderson wrote:

> On 10/09/2013 04:26 PM, Joseph S. Myers wrote:
> > David, Richard: I think the SPARC and Alpha uses of soft-fp could
> > benefit from this.  Alpha already does something similar of its own
> > regarding redefining FP_ROUNDMODE, while if the relevant SPARC files
> 
> I'm not sure this is applicable to Alpha.
> 
> The thing Alpha does wrt redefining FP_ROUNDMODE is to handle
> a couple of routines that are defined to take the rounding mode
> as an argument rather than taking it from the fp control register.

I'm thinking of ots_cvtqux.c, ots_cvtqx.c and ots_cvttx.c defining 
FP_ROUNDMODE to FP_RND_ZERO - those being equivalent to floatunditf.c, 
floatditf.c and extenddftf2.c, the first two of which define 
FP_NO_EXCEPTIONS (and so don't need FP_DECL_EX or anything else related to 
exceptions).  I think ots_cvtqux.c and ots_cvtqx.c should be able to 
define FP_NO_EXCEPTIONS (and then not need the local FP_ROUNDMODE 
definitions for anything), while the FP_ROUNDMODE definition in 
ots_cvttx.c shouldn't actually be doing anything (none of the macros there 
does any rounding; I haven't checked, but likely the definition dates back 
to when there was a single macro for all floating-point conversions rather 
than separate ones for extensions and truncations).

-- 
Joseph S. Myers
joseph@codesourcery.com