Re: "Mini" tags to reduce the number of op codes

BGB-Alt wrote:

On 4/11/2024 9:30 AM, Scott Lurndal wrote:

"Paul A. Clayton" <paaronclayton@gmail.com> writes:

 

One thing that is still needed is a good, fast, and semi-accurate way to pull off the Z=1.0/Z' calculation, as needed for perspective-correct rasterization (affine requires subdivision, which adds cost to the front-end, and interpolating Z directly adds significant distortion for geometry near the near plane).

I saw a 10-cycle latency 1-cycle throughput divider at Samsumg::
10 stages of 3-bit at a time SRT divider with some exponent stuff on the side. 1.0/z is a lot simpler than that (float only). A lot
of these great big complicated calculations can be beaten into
submission with a clever attack of brute force HW.....FMUL and FMAC
being the most often cited cases.