+extern void mp_gcd(mp **/*gcd*/, mp **/*xx*/, mp **/*yy*/,
+ mp */*a*/, mp */*b*/);
+
+/* -- @mp_modinv@ --- *
+ *
+ * Arguments: @mp *d@ = destination
+ * @mp *x@ = argument
+ * @mp *p@ = modulus
+ *
+ * Returns: The inverse %$x^{-1} \bmod p$%.
+ *
+ * Use: Computes a modular inverse. An assertion fails if %$p$%
+ * has no inverse.
+ */
+
+extern mp *mp_modinv(mp */*d*/, mp */*x*/, mp */*p*/);
+
+/* --- @mp_jacobi@ --- *
+ *
+ * Arguments: @mp *a@ = an integer less than @n@
+ * @mp *n@ = an odd integer
+ *
+ * Returns: @-1@, @0@ or @1@ -- the Jacobi symbol %$J(a, n)$%.
+ *
+ * Use: Computes the Jacobi symbol. If @n@ is prime, this is the
+ * Legendre symbol and is equal to 1 if and only if @a@ is a
+ * quadratic residue mod @n@. The result is zero if and only if
+ * @a@ and @n@ have a common factor greater than one.
+ */
+
+extern int mp_jacobi(mp */*a*/, mp */*n*/);
+
+/* --- @mp_modsqrt@ --- *
+ *
+ * Arguments: @mp *d@ = destination integer
+ * @mp *a@ = source integer
+ * @mp *p@ = modulus (must be prime)
+ *
+ * Returns: If %$a$% is a quadratic residue, a square root of %$a$%; else
+ * a null pointer.
+ *
+ * Use: Returns an integer %$x$% such that %$x^2 \equiv a \pmod{p}$%,
+ * if one exists; else a null pointer. This function will not
+ * work if %$p$% is composite: you must factor the modulus, take
+ * a square root mod each factor, and recombine the results
+ * using the Chinese Remainder Theorem.
+ *
+ * We guarantee that the square root returned is the smallest
+ * one (i.e., the `positive' square root).
+ */
+
+extern mp *mp_modsqrt(mp */*d*/, mp */*a*/, mp */*p*/);
+
+/* --- @mp_modexp@ --- *
+ *
+ * Arguments: @mp *d@ = fake destination
+ * @mp *x@ = base of exponentiation
+ * @mp *e@ = exponent
+ * @mp *n@ = modulus (must be positive)
+ *
+ * Returns: The value %$x^e \bmod n$%.
+ */
+
+extern mp *mp_modexp(mp */*d*/, mp */*x*/, mp */*e*/, mp */*n*/);
+
+/*----- Test harness support ----------------------------------------------*/
+
+#include <mLib/testrig.h>
+
+#ifndef CATACOMB_MPTEXT_H
+# include "mptext.h"
+#endif
+
+extern const test_type type_mp;