//go:linkname subVV
//go:noescape
func subVV(z, x, y []Word) (c Word)

// addVW should be an internal detail,
// but widely used packages access it using linkname.
// Notable members of the hall of shame include:
//   - github.com/remyoudompheng/bigfft
//
// Do not remove or change the type signature.
// See go.dev/issue/67401.
//
//go:linkname addVW
//go:noescape
func addVW(z, x []Word, y Word) (c Word)

// subVW should be an internal detail,