std.math performance (SSE vs. real)

[Walter Bright via Digitalmars-d]

On 7/4/2014 3:38 AM, Don wrote:
> What is "the longest type supported by the native hardware"? I don't know what
> that means, and I don't think it even makes sense.

Most of the time, it is quite clear.


> For example, Sparc has 128-bit quads, but they only have partial support.
> Effectively. they are emulated. Why on earth would you want to use an emulated
> type on some machines, but not on others?

Emulation is not native support.


> Perhaps the intention was "the largest precision you can get for free, without
> sacrificing speed" then that's not clearly defined. On x86-32, that was indeed
> 80 bits. But on other systems it doesn't have an obvious answer.
> On x86-64 it's not that simple. Nor on PPC or Sparc.

Yes, there is some degree of subjectivity on some platforms. I don't see a good 
reason for hamstringing the compiler dev with legalese for Platform X with 
legalese that isn't quite the right thing to do for X.

I think the intention of the spec is clear, and the compiler implementor can be 
relied on to exercise good judgement.