// but it turns out that a number of implementations (namely, the Java
		// jar tool) don't properly set the storage method on directories
		// resulting in a file with compressed size > 0 but uncompressed size ==
		// 0. We still want to fail when a directory has associated uncompressed
		// data, but we are tolerant of cases where the uncompressed size is
		// zero but compressed size is not.
		if f.UncompressedSize64 != 0 {

</p>

<p>
On machines where <code>SP</code> and <code>PC</code> are
traditionally aliases for a physical, numbered register,
in the Go assembler the names <code>SP</code> and <code>PC</code>
are still treated specially;
for instance, references to <code>SP</code> require a symbol,
much like <code>FP</code>.
To access the actual hardware register use the true <code>R</code> name.

func (rbs *readBadSeeker) Seek(int64, int) (int64, error) { return 0, fmt.Errorf("illegal seek") }

// TestReadTruncation test the ending condition on various truncated files and
// that truncated files are still detected even if the underlying io.Reader
// satisfies io.Seeker.
func TestReadTruncation(t *testing.T) {
	var ss []string
	for _, p := range []string{
		"testdata/gnu.tar",
		"testdata/ustar-file-reg.tar",

// A nil argument is equivalent to an empty slice.
func Compare(a, b []byte) int {
	return bytealg.Compare(a, b)
}

// explode splits s into a slice of UTF-8 sequences, one per Unicode code point (still slices of bytes),
// up to a maximum of n byte slices. Invalid UTF-8 sequences are chopped into individual bytes.
func explode(s []byte, n int) [][]byte {
	if n <= 0 || n > len(s) {
		n = len(s)
	}
	a := make([][]byte, n)

	"sync"
	"syscall"
)

func adbRun(args string) (int, error) {
	// The exit code of adb is often wrong. In theory it was fixed in 2016
	// (https://code.google.com/p/android/issues/detail?id=3254), but it's
	// still broken on our builders in 2023. Instead, append the exitcode to
	// the output and parse it from there.
	filter, exitStr := newExitCodeFilter(os.Stdout)
	args += "; echo -n " + exitStr + "$?"

	cmd := adbCmd("exec-out", args)

	// in CP-437 (which is mostly compatible with ASCII), unless the UTF-8
	// flag bit is set. However, there are several problems:
	//
	//	* Many ZIP readers still do not support UTF-8.
	//	* If the UTF-8 flag is cleared, several readers simply interpret the
	//	name and comment fields as whatever the local system encoding is.
	//

and less like C and C++, where the meaning of any program with a race
is entirely undefined, and the compiler may do anything at all.
Go's approach aims to make errant programs more reliable and easier to debug,
while still insisting that races are errors and that tools can diagnose and report them.
</p>

<h2 id="model">Memory Model</h2>

<p>
The following formal definition of Go's memory model closely follows