rno = uint16(r)
		} else {
			rno = uint16(inst.Args[0].(RegSP))
		}
		if rno <= uint16(WZR) {
			op = "MOVW" + suffix
		} else if rno >= uint16(B0) && rno <= uint16(B31) {
			op = "FMOVB" + suffix
			args[0] = fmt.Sprintf("F%d", rno&31)
		} else if rno >= uint16(H0) && rno <= uint16(H31) {
			op = "FMOVH" + suffix
			args[0] = fmt.Sprintf("F%d", rno&31)
		} else if rno >= uint16(S0) && rno <= uint16(S31) {

    bufferHelper(
        "\nempty first line\nno newline at end", "\n", "empty first line\n", "no newline at end");
    bufferHelper("three\rlines\rno newline at end", "three\r", "lines\r", "no newline at end");
    bufferHelper("mixed\nline\rendings\r\n", "mixed\n", "line\r", "endings\r\n");
  }

  private static final int[] CHUNK_SIZES = {1, 2, 3, Integer.MAX_VALUE};

    bufferHelper(
        "\nempty first line\nno newline at end", "\n", "empty first line\n", "no newline at end");
    bufferHelper("three\rlines\rno newline at end", "three\r", "lines\r", "no newline at end");
    bufferHelper("mixed\nline\rendings\r\n", "mixed\n", "line\r", "endings\r\n");
  }

  private static final int[] CHUNK_SIZES = {1, 2, 3, Integer.MAX_VALUE};

		readTo := func(delim byte, want string) {
			data, err := read(r, delim)
			if err != nil {
				t.Fatalf("#%d: unexpected error reading to %c: %v", rno, delim, err)
			}
			if got := string(data); got != want {
				t.Fatalf("#%d: got %q, want %q", rno, got, want)
			}
		}

		// Read the data with occasional UnreadByte calls.
		for i := 0; i < n; i++ {
			readTo('d', "abcd")
			for j := 0; j < 3; j++ {