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    SubjectRe: How to use floating point in a module?
    Date
    Måns Rullgård wrote:
    > Floating point is forbidden in kernel code since the floating point
    > registers (and other floating point context) is not saved/restored
    > during system calls, for efficiency. I'm speculating here, but it
    > might be possible to manually save the floating point context while
    > doing some floating point operations. The problem arises if this code
    > is interrupted midway. Using a preemptive 2.6 kernel would easily
    > break here.

    What about adding some functions such as enable_fpreg_syscalls() and
    disable_fpreg_syscalls() that could be called before and after any floating
    point operations? They could set a flag somewhere that would cause the
    float registers to be saved/restored. Forgive me if this is somehow stupid.
    I'm very much a kernel newbie.

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