3 ms·

But then why does python and JavaScript on the same machines get it right?

• nitrogen 6y ago
  Unsure: compiled to use SSE instead of x87 for fpmath?
• stefan_ 6y ago
  Because it's now getting exceedingly rare to find a program that was not compiled with at least SSE instructions enabled. So the x87 FPU is simply not used then.
• nwallin 6y ago
  Because they're compiled to use SSE instructions instead of x87 FPU instructions. If you are still writing 32 bit x86 C code, it's probably some embedded or legacy CPU, and it's wrong to assume SSE instructions are available. So GCC correctly defaults to using FPU instructions instead of SSE instructions on 32 bit x86. Javascript and python will basically never be run in embedded environments, and their legacy environments probably aren't that legacy that SSE instructions aren't available. So it's reasonable to default to SSE.
  • admax88q 6y ago
    Plus JavaScript is interpreted and JITed, it can detect and decide at runtime whether to use SSE or x87.
  • fulafel 6y ago
    There is a lot of Python out there running in embedded environments, some quite old. Python is 30 years old after all.
• pwdisswordfish2 6y ago
  Python IIRC stores intermediate results in memory, it doesn't perform long chains of calculations entirely in FPU registers. This ensures the intermediate results are predictably rounded. JavaScript JITs blindly use SSE without checking if it is available. Bytecode interpreters behave the same as above.