func (r RotateParams) InMask() uint64 {
	return bits.RotateLeft64(r.OutMask(), -int(r.Amount))
}

// OutMerge tries to generate a new set of parameters representing
// the intersection between the selected bits and the provided mask.
// If the intersection is unrepresentable (0 or not contiguous) nil
// will be returned.
func (r RotateParams) OutMerge(mask uint64) *RotateParams {
	mask &= r.OutMask()
	if mask == 0 {
		return nil
	}

	}

	for _, test := range tests {
		if r := test.src.InMerge(test.mask); !eq(r, test.in) {
			t.Errorf("%v merged with %#x (input): want %v, got %v", test.src, test.mask, test.in, r)
		}
		if r := test.src.OutMerge(test.mask); !eq(r, test.out) {
			t.Errorf("%v merged with %#x (output): want %v, got %v", test.src, test.mask, test.out, r)
		}
	}