You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: sbox_ref.go
    path of file: ./repos/podman/vendor/github.com/aead/serpent
    
    the code of the file until where you have to start completion: // Copyright (c) 2016 Andreas Auernhammer. All rights reserved.
// Use of this source code is governed by a license that can be
// found in t
    
func sb2Inv(r0, r1, r2, r3 *uint32) {
	v0 := *r0 // save r0
	v3 := *r3 // save r3
	t0 := *r1 ^ v3
	t1 := ^t0
	t2 := v0 ^ *r2
	t3 := *r2 ^ t0
	t4 := *r1 & t3
	*r0 = t2 ^ t4
	t5 := v0 | t1
	t6 := v3 ^ t5
	t7 := t2 | t6
	*r3 = t0 ^ t7
	t8 := ^t3
	t9 := *r0 | *r3
	*r1 = t8 ^ t9
	*r2 = (v3 & t8) ^ (t2 ^ t9)
}