}
				return 5, errors.New("5-then-error")
			}),
			n:            4,
			want:         4,
			wantErr:      nil,
			wantBuffered: 1,
		},
		{
			name: "fill error, discard equal",
			r: newScriptedReader(func(p []byte) (n int, err error) {
				if len(p) < 5 {
					panic("unexpected small read")
				}
				return 5, errors.New("5-then-error")
			}),
			n:            5,

	// which names a file in the testdata/ directory containing the
	// uncompressed expected content.
	// If content is very large, an alternative to setting Content or File
	// is to set Size, which will then be checked against the header-reported size
	// but will bypass the decompressing of the actual data.
	// This last option is used for testing very large (multi-GB) compressed files.
	ContentErr error
	Content    []byte

	// function arguments only once while doing pointer checks.
	// This is particularly useful when passing additional arguments
	// to _cgoCheckPointer, as done in checkIndex and checkAddr.
	//
	// When the function argument is a conversion to unsafe.Pointer,
	// we unwrap the conversion before checking the pointer,
	// and then wrap again when calling C.f. This lets us check
	// the real type of the pointer in some cases. See issue #25941.

	VREV64	V2.S2, V3.S2                    // 4308a00e
	VREV64	V2.S4, V3.S4                    // 4308a04e

// logical ops
//
// make sure constants get encoded into an instruction when it could
	AND	R1@>33, R2
	AND	$(1<<63), R1                        // AND	$-9223372036854775808, R1       // 21004192
	AND	$(1<<63-1), R1                      // AND	$9223372036854775807, R1        // 21f84092

			}
		}
	}
}

// test a small index across all page offsets
func TestIndexByteSmall(t *testing.T) {
	b := make([]byte, 5015) // bigger than a page
	// Make sure we find the correct byte even when straddling a page.
	for i := 0; i <= len(b)-15; i++ {
		for j := 0; j < 15; j++ {
			b[i+j] = byte(100 + j)
		}
		for j := 0; j < 15; j++ {
			p := IndexByte(b[i:i+15], byte(100+j))
			if p != j {