On 2019-Mar-13 23:30:07 -0700, Steve Kargl <s...@troutmask.apl.washington.edu> wrote: >AFAICT, all libm float routines need to be modified to conditional >include ieeefp.h and call fpsetprec(FP_PD). This will work around >issues is FP and libm. FreeBSD needs to issue an erratum about >the numerical issues with clang.
I vaguely recall looking into the x87 initialisation a long time ago and STR that the startup code (either crtX or in the kernel) does a fninit() to set the precision. I don't recall exactly where. IMO, calling fpsetprec() in every libm float function is overkill. It should be enough to fpsetprec() before main() and add a note in the man pages that libm is built to use the default FPU configuration and changing the configuration (precision or rounding) may result in larger errors. -- Peter Jeremy
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