X-Git-Url: https://git.distorted.org.uk/u/mdw/catacomb/blobdiff_plain/d34decd2b2b88240cf4ca68a2a5feb7bf36de6e7..2685767a6125c1620719c7de6234aedf41857b7e:/mp.h

diff --git a/mp.h b/mp.h
index 92f1209..dcf4349 100644
--- a/mp.h
+++ b/mp.h
@@ -1,6 +1,6 @@
 /* -*-c-*-
  *
- * $Id: mp.h,v 1.7 2000/06/17 11:45:09 mdw Exp $
+ * $Id: mp.h,v 1.11 2001/04/03 19:36:05 mdw Exp $
  *
  * Simple multiprecision arithmetic
  *
@@ -30,6 +30,20 @@
 /*----- Revision history --------------------------------------------------* 
  *
  * $Log: mp.h,v $
+ * Revision 1.11  2001/04/03 19:36:05  mdw
+ * Add some simple bitwise operations so that Perl can use them.
+ *
+ * Revision 1.10  2000/10/08 12:03:16  mdw
+ * Provide @mp_eq@ and @MP_EQ@ for rapidly testing equality of two
+ * integers.
+ *
+ * Revision 1.9  2000/07/29 17:03:31  mdw
+ * Add support for left-to-right bitscanning, for use in modular
+ * exponentiation.
+ *
+ * Revision 1.8  2000/06/22 19:02:01  mdw
+ * Add new functions.
+ *
  * Revision 1.7  2000/06/17 11:45:09  mdw
  * Major memory management overhaul.  Added arena support.  Use the secure
  * arena for secret integers.  Replace and improve the MP management macros
@@ -417,13 +431,36 @@ extern void mp_scan(mpscan */*sc*/, const mp */*m*/);
   MPSCAN_INITX(_sc, _mm->v, _mm->vl);					\
 } while (0)
 
+/* --- @mp_rscan@ --- *
+ *
+ * Arguments:	@mpscan *sc@ = pointer to bitscanner block
+ *		@const mp *m@ = pointer to a multiprecision integer
+ *
+ * Returns:	---
+ *
+ * Use:		Initializes a reverse bitscanner on a multiprecision
+ *		integer.
+ */
+
+extern void mp_rscan(mpscan */*sc*/, const mp */*m*/);
+
+#define MP_RSCAN(sc, m) do {						\
+  const mp *_mm = (m);							\
+  mpscan *_sc = (sc);							\
+  MPSCAN_RINITX(_sc, _mm->v, _mm->vl);					\
+} while (0)
+
 /* --- Other bitscanning aliases --- */
 
 #define mp_step mpscan_step
 #define mp_bit mpscan_bit
+#define mp_rstep mpscan_rstep
+#define mp_rbit mpscan_rbit
 
 #define MP_STEP MPSCAN_STEP
 #define MP_BIT MPSCAN_BIT
+#define MP_RSTEP MPSCAN_RSTEP
+#define MP_RBIT MPSCAN_RBIT
 
 /*----- Loading and storing -----------------------------------------------*/
 
@@ -566,6 +603,19 @@ extern mp *mp_lsl(mp */*d*/, mp */*a*/, size_t /*n*/);
 
 extern mp *mp_lsr(mp */*d*/, mp */*a*/, size_t /*n*/);
 
+/* --- @mp_eq@ --- *
+ *
+ * Arguments:	@const mp *a, *b@ = two numbers
+ *
+ * Returns:	Nonzero if the numbers are equal.
+ */
+
+extern int mp_eq(const mp */*a*/, const mp */*b*/);
+
+#define MP_EQ(a, b)							\
+  ((((a)->f ^ (b)->f) & MP_NEG) == 0 &&					\
+   mpx_ueq((a)->v, (a)->vl, (b)->v, (b)->vl))
+
 /* --- @mp_cmp@ --- *
  *
  * Arguments:	@const mp *a, *b@ = two numbers
@@ -578,6 +628,19 @@ extern int mp_cmp(const mp */*a*/, const mp */*b*/);
 
 #define MP_CMP(a, op, b) (mp_cmp((a), (b)) op 0)
 
+/* --- @mpx_and@, @mpx_or@, @mpx_xor@, @mpx_not@ --- *
+ *
+ * Arguments:	@mp *d@ = destination
+ *		@mp *a, *b@ = sources
+ *
+ * Returns:	The result of the obvious bitwise operation.
+ */
+
+extern mp *mp_and(mp */*d*/, mp */*a*/, mp */*b*/);
+extern mp *mp_or(mp */*d*/, mp */*a*/, mp */*b*/);
+extern mp *mp_xor(mp */*d*/, mp */*a*/, mp */*b*/);
+extern mp *mp_not(mp */*d*/, mp */*a*/);
+
 /* --- @mp_add@ --- *
  *
  * Arguments:	@mp *d@ = destination
@@ -629,8 +692,39 @@ extern mp *mp_sqr(mp */*d*/, mp */*a*/);
 
 extern void mp_div(mp **/*qq*/, mp **/*rr*/, mp */*a*/, mp */*b*/);
 
+/* --- @mp_odd@ --- *
+ *
+ * Arguments:	@mp *d@ = pointer to destination integer
+ *		@mp *m@ = pointer to source integer
+ *		@size_t *s@ = where to store the power of 2
+ *
+ * Returns:	An odd integer integer %$t$% such that %$m = 2^s t$%.
+ *
+ * Use:		Computes a power of two and an odd integer which, when
+ *		multiplied, give a specified result.  This sort of thing is
+ *		useful in number theory quite often.
+ */
+
+extern mp *mp_odd(mp */*d*/, mp */*m*/, size_t */*s*/);
+
 /*----- More advanced algorithms ------------------------------------------*/
 
+/* --- @mp_sqrt@ --- *
+ *
+ * Arguments:	@mp *d@ = pointer to destination integer
+ *		@mp *a@ = (nonnegative) integer to take square root of
+ *
+ * Returns:	The largest integer %$x$% such that %$x^2 \le a$%.
+ *
+ * Use:		Computes integer square roots.
+ *
+ *		The current implementation isn't very good: it uses the
+ *		Newton-Raphson method to find an approximation to %$a$%.  If
+ *		there's any demand for a better version, I'll write one.
+ */
+
+extern mp *mp_sqrt(mp */*d*/, mp */*a*/);
+
 /* --- @mp_gcd@ --- *
  *
  * Arguments:	@mp **gcd, **xx, **yy@ = where to write the results
@@ -659,7 +753,25 @@ extern void mp_gcd(mp **/*gcd*/, mp **/*xx*/, mp **/*yy*/,
  *		@a@ and @n@ have a common factor greater than one.
  */
 
-int mp_jacobi(mp */*a*/, mp */*n*/);
+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.
+ */
+
+extern mp *mp_modsqrt(mp */*d*/, mp */*a*/, mp */*p*/);
 
 /*----- Test harness support ----------------------------------------------*/