I second this. Worked at Weitek in the 80s and my first job was to write a P754 test suite in C. At that time, Sun engineers wrote a test called “paranoia” and would regularly pick holes in our FPU chip designs. Mostly they ended up taking what we had built and we were in notice they weren’t happy. Then then built their own SPARC FPU and we went to the wall.
I spent months in all the corners of P754 and can attest to it being the most carefully thought through and subtly powerful document.
At this time we built custom FPUs for non P754 such as DEC format which iirc was deliberately close to P754 but slightly twisted to maintain code incompatibility.
Anyone who thinks FPU math is deterministic has not got close to circuit design for these beasts. I suppose MAYBE that got fixed in the last 40 years, but the move to GPU leads me to suspect that determinism in all the myriad corner cases is not top of the list.
I spent months in all the corners of P754 and can attest to it being the most carefully thought through and subtly powerful document.
At this time we built custom FPUs for non P754 such as DEC format which iirc was deliberately close to P754 but slightly twisted to maintain code incompatibility.
Anyone who thinks FPU math is deterministic has not got close to circuit design for these beasts. I suppose MAYBE that got fixed in the last 40 years, but the move to GPU leads me to suspect that determinism in all the myriad corner cases is not top of the list.