Re:I was a 10x engineer and I’m sorry
by Const-me on Thursday July 18, 2019 @04:19PM
(#20473564)
> was working in a space where fast inverse square root was the difference between the program working and it not working
Pentium 3 released in January 1999. That CPU, along with all newer ones, support SSE which has RSQRTPS instruction, faster, also much more precise approximation.
AMD had it before, PFRSQIT1 / PFRCPIT2 in 3DNow from 1998.
Quake 3 Arena released in December 1999. The point of using that approximation is running on older hardware, like Pentium and Pentium 2.
Pentium 3 released in January 1999. That CPU, along with all newer ones, support SSE which has RSQRTPS instruction, faster, also much more precise approximation.
AMD had it before, PFRSQIT1 / PFRCPIT2 in 3DNow from 1998.
Quake 3 Arena released in December 1999. The point of using that approximation is running on older hardware, like Pentium and Pentium 2.