Aaaah, ok. Thank you very much for alrifying this long-standing question!
----- Original Message ----- From: Tomas Hajny via fpc-pascal <fpc-pascal@lists.freepascal.org> To: FPC-Pascal users discussions <fpc-pascal@lists.freepascal.org> Sent: Thursday, February 22, 2024, 15:25:34 Subject: [fpc-pascal] Floating point question On 2024-02-22 15:08, Thomas Kurz via fpc-pascal wrote: >> If you're using Win64, then the answer is simple: x86_64-win64 unlike >> any >> other x86 target does not support Extended, so neither the compiler >> nor the >> code in runtime will ever calculate anything with that precision. > That's another thing I've never understood. How can it depend on the > OS? It's the CPU which does math, and I don't understand what the OS > has to do with that? If amd64 architecture didn't support the > extended-type at all, I'd say "ok". But it's supported on Linux but > not on Windows? Huh? The reason is that the operating system is among others responsible for controlling the multitasking. That includes saving the context of the originally active task and restoring the context of the new task to the original state before it was interrupted. If Win64 doesn't guarantee restoring FPU registers specific to the extended type, using this type would get you into troubles despite its support in the FPU. Tomas _______________________________________________ fpc-pascal maillist - fpc-pascal@lists.freepascal.org https://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal _______________________________________________ fpc-pascal maillist - fpc-pascal@lists.freepascal.org https://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal
