> Even through the 90s, long after many system calls became formalized, floating point math was much more expensive than integer math. IIRC the main reason flo

> Even through the 90s, long after many system calls became formalized, floating point math was much more expensive than integer math. IIRC the main reason floating point numbers weren’t used in system calls back in the 90-ties was that kernel code couldn’t use the CPUs floating point registers, or they would have to be saved at the entry point of each system call and restored before returning to user space. This was deemed too expensive.