On Friday, 27 May 2016 at 09:11:01 UTC, Era Scarecrow wrote:
Hmmm it just occurs to me I made a big assumption. I assumed
that if the CPU supports 64bit operations, that it would be
compiled to use 64bit registers when possible. I'm assuming
this is not the case. As such the tests I was doing will
probably be of little help _unless_ it was X86_64 code, or a
check that verifies it's 64bit hardware?
You have to write your code three times, one for
version(D_InlineAsm_X86)
version (D_InlineAsm_X86_64)
and a version without assembly.
In rare cases you can merge D_InlineAsm_X86 and
D_InlineAsm_X86_64 versions. D provides unfortunately less
support to write code that is valid in both compared to C++! This
causes lots of duplication </rant>
TBH I don't know how to access members in assembly, I think you
shouldn't ever do that. It will depend heavily on the particular
calling convention called.
Just put these fields in local variables.
void increment()
{
auto lo_local = lo;
auto hi_local = hi;
asm
{
add dword ptr lo_local, 1;
adc dword ptr hi_local, 0;
}
lo = lo_local;
hi = hi_local;
}
The compiler will replace with the right register-indexed stuff.
But honestly I doubt it will be any faster because on the other
hand you mess with the optimizer.
