asm woes...

[Era Scarecrow via Digitalmars-d-learn]

On Friday, 27 May 2016 at 09:22:49 UTC, Guillaume Piolat wrote:
> You have to write your code three times, one for
>
> version(D_InlineAsm_X86)
> version (D_InlineAsm_X86_64)
> and a version without assembly.

  Rather than make a new thread I wonder if struct inheritance 
wouldn't solve this, as trying to manage specific versions, lack 
of versions, checks for CTFE all became a headache. and bloated a 
4 line function (2 of which were the opening/declaration) to 
something like 20 lines and looks like a huge mess.

  So...

  Let's assume structs as they are don't (otherwise) change.
  Let's assume structs can be inherited.
  Let's assume inherited structs change _behavior_ only 
(overridden functions as final), but don't add/expand any new 
data (non-polymorphic, no vtables).

  Then I could do something like this!

   //contains plain portable version
   struct base {}

   version(X86) {
     struct inherited : base {
       //only adds or replaces functions, no data changes
       //all asm injection is known to be 32bit x86
     }
   }
   version(X86_64) {
     ...
   }

  Truthfully going with my example, only a couple functions would 
be considered, namely multiply and divide as they would be the 
slowest ones, while everything else has very little to improve 
on, at least based on how wideint.d was implemented.