/** Returns a^2 mod m. */
    abstract long squareMod(long a, long m);

    /** Returns a^p mod m. */
    private long powMod(long a, long p, long m) {
      long res = 1;
      for (; p != 0; p >>= 1) {
        if ((p & 1) != 0) {
          res = mulMod(res, a, m);
        }
        a = squareMod(a, m);
      }
      return res;
    }

1F14A         ; mapped                 ; 0068 0076     # 5.2  SQUARED HV
1F14B         ; mapped                 ; 006D 0076     # 5.2  SQUARED MV
1F14C         ; mapped                 ; 0073 0064     # 5.2  SQUARED SD
1F14D         ; mapped                 ; 0073 0073     # 5.2  SQUARED SS
1F14E         ; mapped                 ; 0070 0070 0076 #5.2  SQUARED PPV

    *   DType is no longer convertible to an int. Use `dtype.as_datatype_enum`
        instead of `int(dtype)` to get the same result.
    *   Support both binary and -1/1 label input in v2 hinge and squared hinge
        losses.
    *   Added `LinearOperator.adjoint` and `LinearOperator.H` (alias).
    *   Expose CriticalSection in core as `tf.CriticalSection`.
    *   Enhanced graphviz output.