[fpc-devel] Optimization theory

J. Gareth Moreton gareth at moreton-family.com
Sun Jun 17 20:36:57 CEST 2018


 Aah, I was in error. I used agner as my source, but even that says 5
cycles for a near call and 17-33 for a far call, so I'm not sure where I
got 50 from. My apologies. I have probably been avoiding function calls
more than necessary!

 Gareth aka. Kit

 On Sun 17/06/18 18:06 , David Pethes public at satd.sk sent:
 Hi, 

 On 17. 6. 2018 12:16, J. Gareth Moreton wrote: 
 > The issue with DivMod is that the saving isn't that great because of the

 > penalty of calling a subroutine, which amounts to around 50 cycles on 
 > x86-64, about equal to DIV. 

 That number sounds awfully high, what's your source? 

 David 

 
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