start on SIMD documentation

[Andrei Alexandrescu]

On 1/13/12 4:57 PM, Walter Bright wrote:
> On 1/13/2012 2:31 PM, Andrei Alexandrescu wrote:
>> People will want to pass a variable for op. Would that work?
>
> It'll currently fail miserably - it has to be a constant. Otherwise, we
> have runtime code generation. While not impossible, it is a large
> increase in scope.

Then probably the operation should be simd!opcode(arguments). If a 
function is intrinsic it shouldn't have special syntactic rights.

Andrei