zynq-rs/libcortex_a9/src/fpu.rs

use core::arch::asm;
/// Enable FPU in the current core.
/// You must execute an ISB immediately after an update of the CPACR.
/// https://developer.arm.com/documentation/ddi0388/i/system-control/register-descriptions/coprocessor-access-control-register
pub fn enable_fpu() {
    unsafe {
        asm!("
            mrc p15, 0, r1, c1, c0, 2
            orr r1, r1, (0b1111<<20)
            mcr p15, 0, r1, c1, c0, 2
            isb
            vmrs r1, fpexc
            orr r1, r1, (1<<30)
            vmsr fpexc, r1
            ", out("r1") _);
    }
}