Re: m68k softfloat builds

[christos%astron.com@localhost (Christos Zoulas)]

In article <20080528020833.GA25377%pix.net@localhost>, Kurt J. Lidl 
<lidl%pix.net@localhost> wrote:
>A while ago, I ran into a problem trying to build a m68k system
>with -msoft-float.  A reply about the failure is here:
>
>http://mail-index.netbsd.org/tech-toolchain/2008/05/04/msg000186.html
>
>Any thoughts about whether or not this is the best way to procede?

The patch referenced there should be applied regardless if we don't have it
yet.

>I suppose that turning on something like the multilib support in gcc
>is another way of doing this -- at least that is my understanding
>of it.
>
>I think this is a larger relevance than just the existing m68k ports
>too.  The Freescale Coldfire chips (the 54xx and 54xxx) have an
>MMU but none have a floating point unit.  The gcc 4.3 compiler
>has support for the coldfire instruction sets (there are slight
>differences between them all).  I've fooled around a bit with
>trying to get gcc 4.3 to build as a cross compiler for netbsd-current,
>but haven't had any success yet.
>
>If anybody wants to get netbsd running on the coldfire (I certainly
>do), I think that this whole issue of no-fpu 68k-ish systems will
>need to be addressed.

We have many choices:
1. always put the softfloat glue in libgcc; pros: no magic library selection,
   easier build process. cons: some size overhead in libgcc [I don't think it
   is much].
2. build the softfloat glue only on machines that need it; pros: efficient.
   cons: complex build process, need to figure out crosscompiling, different
   userland flavors for the same platform.
3. build the softfloat glue in a separate library, and auto-load it using
   ld.so magic. pros: efficient. cons: more complicated than building a
   single library, relies on ld.so magic.

My order of preference is best to worst 1, 3, 2. Others? Other ideas?

christos