How to Trap Floating-Point Exceptions On Rosetta 2

Question

In a related question, How to trap floating-point exceptions on M1 Macs?, someone wanted to understand how to make the following code work natively on macOS hosted by a machine using the M1 processor:

#include <cmath>        // for sqrt()                                           
#include <csignal>      // for signal()                                         
#include <iostream>
#include <xmmintrin.h>  // for _mm_setcsr                                       

void fpe_signal_handler(int /*signal*/) {
  std::cerr << "Floating point exception!\n";
  exit(1);
}

void enable_floating_point_exceptions() {
 _mm_setcsr(_MM_MASK_MASK & ~_MM_MASK_INVALID);
 signal(SIGFPE, fpe_signal_handler);
}

int main() {
  const double x{-1.0};
  std::cout << sqrt(x) << "\n";
  enable_floating_point_exceptions();
  std::cout << sqrt(x) << "\n";
}

I am looking at this from another angle, and want to understand why it doesn't work using Rosetta 2. I compiled it using the following command:

clang++ -g -std=c++17 -arch x86_64 -o fpe fpe.cpp

When I run it, I see the following output:

nan
nan

Mind you, when I do the same thing on a Intel-based Mac, I see the following output:

nan
Floating point exception!

Does anyone know if it is possible to trap floating-point exceptions on Rosetta 2?

Answer 1

Considering the difference in trapping on Intel using:

_mm_setcsr(_MM_MASK_MASK & ~_MM_MASK_INVALID);

and trapping on Apple Silicon using:

fegetenv(&env);
env.__fpcr = env.__fpcr | __fpcr_trap_invalid;
fesetenv(&env);

it seems more likely it is a bug in the Rosetta implementation.