I also tried this:

```rust
    pub fn sqrt_cortex_m4f(val: f32) -> f32 {
        let result: f32;
        unsafe {
            core::arch::asm!(
                "vsqrt.f32 {result}, {input}",
                input = in(sreg) val,
                result = out(sreg) result,
            );
        }
        result
    }
```