Daniel Gibson wrote:
Daniel Gibson schrieb:
Daniel Gibson schrieb:
Walter Bright schrieb:
Daniel Gibson wrote:
BTW: What were the reasons to pass static arrays by value in D2
(while in D1 they're passed by reference)?
It makes things like vectors (i.e. float[3]) natural to manipulate.
It also segues nicely into hopeful future support for the CPU's
vector instructions.
Why can't that be done when the static arrays are passed by reference?
Ah I guess you mean something like "alias float[3] vec3", so one may
expect vec3 to behave like a value type (like when you define it in a
struct) so it's passed by value.
That does make sense, even though I'm not sure what's more important:
consistency between different kinds of arrays or expectations towards
typed defined from static arrays. ;-)
I still don't get the part with the CPU's vector instructions though.
I don't have any assembly knowledge an no experience with directly
using CPU's vector instructions, but the example of a C function
wrapping SSE instructions from the wikipedia article[1], which
multiplies two arrays of floats, loads the arrays by reference and
even stores the result in one of them.
Hrm forgot the link:
[1] http://en.wikipedia.org/wiki/Vector_processor
You don't write an add function by using references to ints. The vector
instructions treat them like values, so a value type should correspond to it.
