How to deal with inline asm functions in Phobos/druntime?

Kai Nacke via digitalmars-d-ldc digitalmars-d-ldc at
Wed Apr 8 04:55:29 PDT 2015

On Wednesday, 8 April 2015 at 11:29:26 UTC, David Nadlinger wrote:
> Speaking about performance: Haven't we switched to 64 bit reals 
> on
> Win64 for the time being? If so, we'd probably want a version 
> of ilogb
> that uses SSE instead of the x87 FPU. This is probably (I'm 
> rather
> sure, but did not measure it) a much bigger performance problem 
> than
> any overly long general purpose register pushing/popping 
> prologues
> generated by non-naked asm functions.

Yes, reals are 64bit on Win64. Using SSE can really help here.
Speaking of performance: The only way to know the some piece of 
code is faster is to measure it. This can reveal surprising 
insights.... (Hint!)

> ilogb() does not seem to be a commonly used function, though, 
> so it
> might not be worth the effort.

There are lot of other functions, too. E.g. the inline assembler 
in expi() is commented because of a problem with the asm parser. 
I think Johan will find enough worthwhile targets.


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