Floating point operations are not deterministic in other situations
That article was written in 2013. A decade has passed, and in modern world these situations became rather rare.
x87 FPU is deprecated and not used by 64-bit programs. Returns values are passed in XMM0 register. Temporary values are either FP32 or FP64. Modern C++ compilers evaluate FP expression from left to right, and they don't use FMA unless explicitly allowed with -ffast-math or /fp:fast compiler switch. Programmers rarely using estimate instructions because modern CPUs complete precise division and square root in 10-15 cycles, little profit from the faster approximations.
The only variable thing which remains is MXCSR register in the thread state.
I would have to re-implement the lib math routines anyway (in my case cbrt and pow)
Or you can copy-paste them from OpenBSD. The license is permissive, they are implemented in C without assembly, and the code quality is pretty good.
Comments
That article was written in 2013. A decade has passed, and in modern world these situations became rather rare.
x87 FPU is deprecated and not used by 64-bit programs. Returns values are passed in XMM0 register. Temporary values are either FP32 or FP64. Modern C++ compilers evaluate FP expression from left to right, and they don't use FMA unless explicitly allowed with -ffast-math or /fp:fast compiler switch. Programmers rarely using estimate instructions because modern CPUs complete precise division and square root in 10-15 cycles, little profit from the faster approximations.
The only variable thing which remains is MXCSR register in the thread state.
Or you can copy-paste them from OpenBSD. The license is permissive, they are implemented in C without assembly, and the code quality is pretty good.