After noticing the Quake 3 Rsqrt algorithm in here, I cannot help but question the quality of this whole site. As in - is it grounded in any actual practical reality of writing code for modern hardware?
For reference, Quake style Rsqrt hasn't been practical on x86 for more than a decade, as Intel processors internally separate integer and float SSE registers, and converting between the two is costly.
Instead, they have a built-in intrinsic of _mm_rsqrt_ps which does a limited precision rsqrt in hardware.
> In fact, it is so good that it has been implemented in hardware, so the algorithm is no longer relevant by itself for software engineers, but we are nonetheless going to walk through it for its intrinsic beauty and great educational value.
For reference, Quake style Rsqrt hasn't been practical on x86 for more than a decade, as Intel processors internally separate integer and float SSE registers, and converting between the two is costly.
Instead, they have a built-in intrinsic of _mm_rsqrt_ps which does a limited precision rsqrt in hardware.