Predefined Version expansion

[Jarrett Billingsley]

"Dan" <murpsoft at hotmail.com> wrote in message 
news:eurruh$26gc$1 at digitalmars.com...
> Walter Bright Wrote:
>
> Yes, the GDC and DMD implementations support all the SSE3 instructions, 
> but someone with a i486 Pentium Pro does not, and neither might another D 
> implementation implementing the D language spec.
>
> When I use an SSE3 instruction in D, is it going to raise an error if the 
> person's system is only a Pentium Pro?
>
> If that could be done by checking the CPU support for each instruction 
> implicitly, then it would be even better than versioning it all off... 
> but I don't think that's the case - and it's not specified?
>

Just because their machine doesn't support it, why wouldn't you allow 
someone to use SSE3 instructions?  For that matter, who says you have to be 
running the compiler on an x86 platform to compile to x86 machine code?