Function k_float_enable

pub unsafe extern "C" fn k_float_enable(
    thread: *mut k_thread,
    options: u32,
) -> i32

@brief Enable preservation of floating point context information.

This routine informs the kernel that the specified thread will use the floating point registers.

Invoking this routine initializes the thread’s floating point context info to that of an FPU that has been reset. The next time the thread is scheduled by z_swap() it will either inherit an FPU that is guaranteed to be in a “sane” state (if the most recent user of the FPU was cooperatively swapped out) or the thread’s own floating point context will be loaded (if the most recent user of the FPU was preempted, or if this thread is the first user of the FPU). Thereafter, the kernel will protect the thread’s FP context so that it is not altered during a preemptive context switch.

The @a options parameter indicates which floating point register sets will be used by the specified thread.

For x86 options:

• K_FP_REGS indicates x87 FPU and MMX registers only
• K_SSE_REGS indicates SSE registers (and also x87 FPU and MMX registers)

@warning Some architectures apply restrictions on how the enabling of floating point preservation may be requested, see arch_float_enable.

@warning This routine should only be used to enable floating point support for a thread that currently has such support enabled.

@param thread ID of thread. @param options architecture dependent options

@retval 0 On success. @retval -ENOTSUP If the floating point enabling is not implemented. -EINVAL If the floating point enabling could not be performed.