X-Git-Url: https://git.distorted.org.uk/~mdw/catacomb/blobdiff_plain/ee39a683a2b623a1da0747ec20f20b63470a2db6..8f2287ef5c05d496fcb9b012629af007fe56f897:/math/f25519.h

diff --git a/math/f25519.h b/math/f25519.h
index a70ca2df..4a2a2191 100644
--- a/math/f25519.h
+++ b/math/f25519.h
@@ -55,6 +55,13 @@ typedef union {
 #  define F25519_IMPL 10
 #endif
 
+#if F25519_IMPL == 26
+  typedef int32 f25519_piece;
+#endif
+#if F25519_IMPL == 10
+  typedef int16 f25519_piece;
+#endif
+
 /*----- Functions provided ------------------------------------------------*/
 
 /* --- @f25519_set@ --- *
@@ -108,6 +115,39 @@ extern void f25519_load(f25519 */*z*/, const octet /*xv*/[32]);
 
 extern void f25519_store(octet /*zv*/[32], const f25519 */*x*/);
 
+/* --- @f25519_pick2@ --- *
+ *
+ * Arguments:	@f25519 *z@ = where to put the result (may alias @x@ or @y@)
+ *		@const f25519 *x, *y@ = two operands
+ *		@uint32 m@ = a mask
+ *
+ * Returns:	---
+ *
+ * Use:		If @m@ is zero, set @z = y@; if @m@ is all-bits-set, then set
+ *		@z = x@.  If @m@ has some other value, then scramble @z@ in
+ *		an unhelpful way.
+ */
+
+extern void f25519_pick2(f25519 */*z*/, const f25519 */*x*/,
+			 const f25519 */*y*/, uint32 /*m*/);
+
+/* --- @f25519_pickn@ --- *
+ *
+ * Arguments:	@f25519 *z@ = where to put the result
+ *		@const f25519 *v@ = a table of entries
+ *		@size_t n@ = the number of entries in @v@
+ *		@size_t i@ = an index
+ *
+ * Returns:	---
+ *
+ * Use:		If @0 <= i < n < 32@ then set @z = v[i]@.  If @n >= 32@ then
+ *		do something unhelpful; otherwise, if @i >= n@ then set @z@
+ *		to zero.
+ */
+
+extern void f25519_pickn(f25519 */*z*/, const f25519 */*v*/, size_t /*n*/,
+			 size_t /*i*/);
+
 /* --- @f25519_condswap@ --- *
  *
  * Arguments:	@f25519 *x, *y@ = two operands
@@ -148,6 +188,33 @@ extern void f25519_add(f25519 */*z*/,
 extern void f25519_sub(f25519 */*z*/,
 		       const f25519 */*x*/, const f25519 */*y*/);
 
+/* --- @f25519_neg@ --- *
+ *
+ * Arguments:	@f25519 *z@ = where to put the result (may alias @x@)
+ *		@const f25519 *x@ = an operand
+ *
+ * Returns:	---
+ *
+ * Use:		Set @z = -x@.
+ */
+
+extern void f25519_neg(f25519 */*z*/, const f25519 */*x*/);
+
+/* --- @f25519_condneg@ --- *
+ *
+ * Arguments:	@f25519 *z@ = where to put the result (may alias @x@)
+ *		@const f25519 *x@ = an operand
+ *		@uint32 m@ = a mask
+ *
+ * Returns:	---
+ *
+ * Use:		If @m@ is zero, set @z = x@; if @m@ is all-bits-set, then set
+ *		@z = -x@.  If @m@ has some other value then scramble @z@ in
+ *		an unhelpful way.
+ */
+
+extern void f25519_condneg(f25519 */*z*/, const f25519 */*x*/, uint32 /*m*/);
+
 /* --- @f25519_mulconst@ --- *
  *
  * Arguments:	@f25519 *z@ = where to put the result (may alias @x@)
@@ -200,6 +267,22 @@ extern void f25519_sqr(f25519 */*z*/, const f25519 */*x*/);
 
 extern void f25519_inv(f25519 */*z*/, const f25519 */*x*/);
 
+/* --- @f25519_quosqrt@ --- *
+ *
+ * Arguments:	@f25519 *z@ = where to put the result (may alias @x@ or @y@)
+ *		@const f25519 *x, *y@ = two operands
+ *
+ * Returns:	Zero if successful, @-1@ if %$x/y$% is not a square.
+ *
+ * Use:		Stores in @z@ the one of the square roots %$\pm\sqrt{x/y}$%.
+ *		If %$x = y = 0% then the result is zero; if %$y = 0$% but %$x
+ *		\ne 0$% then the operation fails.  If you wanted a specific
+ *		square root then you'll have to pick it yourself.
+ */
+
+extern int f25519_quosqrt(f25519 */*z*/,
+			  const f25519 */*x*/, const f25519 */*y*/);
+
 /*----- That's all, folks -------------------------------------------------*/
 
 #ifdef __cplusplus