n := len(b) * count

	if len(b) == 0 {
		return []byte{}
	}

	// Past a certain chunk size it is counterproductive to use
	// larger chunks as the source of the write, as when the source
	// is too large we are basically just thrashing the CPU D-cache.
	// So if the result length is larger than an empirically-found
	// limit (8KB), we stop growing the source string once the limit

	ADD $-8589869055, R5            // 3fe0fffe63ff00017bff83e463ff00017cbf2a14 or 0602000138a50001

	//TODO: this compiles to add r5,r6,r0. It should be addi r5,r6,0.
	//      this is OK since r0 == $0, but the latter is preferred.
	ADD $0, R6, R5             	// 7ca60214

        //TODO: the assembler rewrites these into ADDIS $19, R5, Rx and ADD $-10617, Rx, Rx, but the test only sees the first ADDIS

</p>

<p>
In Go object files and binaries, the full name of a symbol is the
package path followed by a period and the symbol name:
<code>fmt.Printf</code> or <code>math/rand.Int</code>.
Because the assembler's parser treats period and slash as punctuation,
those strings cannot be used directly as identifier names.
Instead, the assembler allows the middle dot character U+00B7
and the division slash U+2215 in identifiers and rewrites them to

	for _, tt := range cutTests {
		if before, after, found := Cut([]byte(tt.s), []byte(tt.sep)); string(before) != tt.before || string(after) != tt.after || found != tt.found {
			t.Errorf("Cut(%q, %q) = %q, %q, %v, want %q, %q, %v", tt.s, tt.sep, before, after, found, tt.before, tt.after, tt.found)
		}
	}
}

var cutPrefixTests = []struct {
	s, sep string
	after  string
	found  bool
}{

</pre>

<p>
the variable <code>a</code> will be initialized after <code>b</code> but
whether <code>x</code> is initialized before <code>b</code>, between
<code>b</code> and <code>a</code>, or after <code>a</code>, and
thus also the moment at which <code>sideEffect()</code> is called (before
or after <code>x</code> is initialized) is not specified.
</p>

<p>

	// difference that for some j, a[j]>b[j] and a[j+1]<b[j+1]. If the implementation
	// compares large chunks with wrong endianness, it gets wrong result.
	// no vector register is larger than 512 bytes for now
	const maxLength = 512
	a := make([]byte, maxLength)
	b := make([]byte, maxLength)
	// randomish but deterministic data. No 0 or 255.
	for i := 0; i < maxLength; i++ {

</p>

<p>
Reads of memory locations larger than a single machine word
are encouraged but not required to meet the same semantics
as word-sized memory locations,
observing a single allowed write <i>w</i>.
For performance reasons,
implementations may instead treat larger operations
as a set of individual machine-word-sized operations
in an unspecified order.

			t.Fatal("looping")
		}
	}
	if s.Err() != nil {
		t.Fatal("after scan:", s.Err())
	}
}

func TestBlankLines(t *testing.T) {
	s := NewScanner(strings.NewReader(strings.Repeat("\n", 1000)))
	for count := 0; s.Scan(); count++ {
		if count > 2000 {
			t.Fatal("looping")
		}
	}
	if s.Err() != nil {
		t.Fatal("after scan:", s.Err())
	}
}

type countdown int

			// walking the tree and copying it piecewise. If the directory tree
			// contains nested modules this could push a lot of unnecessary contents,
			// but for the golang.org/x repos it seems to be significantly (~2x)
			// faster than copying one file at a time (via filepath.WalkDir),
			// apparently due to high latency in 'adb' commands.
			if err := adb("push", modDir, deviceModDir); err != nil {
				return 0, err
			}
		} else {

// being valid at the next read call. If Peek returns fewer than n bytes, it
// also returns an error explaining why the read is short. The error is
// [ErrBufferFull] if n is larger than b's buffer size.
//
// Calling Peek prevents a [Reader.UnreadByte] or [Reader.UnreadRune] call from succeeding
// until the next read operation.
func (b *Reader) Peek(n int) ([]byte, error) {
	if n < 0 {