Rust code shared from the playground

playground.rs

unsafe fn exp_rotation_1(x :* mut celt_norm, off :usize,
	len :usize, stride :usize, c :v16, s :v16) {

	let ms = neg16!(s);
	let off = off as isize;
	let stride = stride as isize;
	let len = len as isize;
	let mut xptr = x.offset(off);

	macro_rules! epmm {
		($a:ident, $b:ident, $s:ident) => {
			extract16!(pshr32!(mac16_16!(mult16_16!(c, $a), $s, $b), 15))
		};
	}
	for _ in 0 .. len - stride {
		let x1 = *xptr;
		let x2 = *xptr.offset(stride);
		*xptr.offset(stride) = epmm!(x2, x1, s);
		*xptr = epmm!(x1, x2, ms);
		xptr = xptr.offset(1);
	}
	// Sadly, we can't use Rust slices in this function yet
	// because we are writing to negative indices of X here.
	// We'd have to change it somewhere higher up in the chain.
	// Maybe it would work if we changed it in celt/bands.c...
	xptr = x.offset(off + len - 2 * stride - 1);
	for _ in 0 .. len- 2 * stride {
		let x1 = *xptr;
		let x2 = *xptr.offset(stride);
		*xptr.offset(stride) = epmm!(x2, x1, s);
		*xptr = epmm!(x1, x2, ms);
		xptr = xptr.offset(-1);
	}
}