X-Git-Url: https://git.distorted.org.uk/~mdw/secnet/blobdiff_plain/0bcb8184cfce875a4dde57621139dd44c433f3a5..refs/heads/mdw/xdh:/fgoldi.h

diff --git a/fgoldi.h b/fgoldi.h
index 1857008..37dc6e2 100644
--- a/fgoldi.h
+++ b/fgoldi.h
@@ -1,39 +1,3 @@
-/*
- * fgoldi.h: arithmetic modulo 2^448 - 2^224 - 1
- */
-/*
- * This file is Free Software.  It has been modified to as part of its
- * incorporation into secnet.
- *
- * Copyright 2017 Mark Wooding
- *
- * You may redistribute this file and/or modify it under the terms of
- * the permissive licence shown below.
- *
- * You may redistribute secnet as a whole and/or modify it under the
- * terms of the GNU General Public License as published by the Free
- * Software Foundation; either version 3, or (at your option) any
- * later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, see
- * https://www.gnu.org/licenses/gpl.html.
- */
-/*
- * Imported from Catacomb, and lightly modified for Secnet (2017-04-30):
- *
- *   * Use `fake-mLib-bits.h' in place of the real <mLib/bits.h>.
- *
- *   * Remove the 16/32-bit implementation, since C99 always has 64-bit
- *     arithmetic.
- *
- * The file's original comment headers are preserved below.
- */
 /* -*-c-*-
  *
  * Arithmetic in the Goldilocks field GF(2^448 - 2^224 - 1)
@@ -43,7 +7,26 @@
 
 /*----- Licensing notice --------------------------------------------------*
  *
- * This file is part of Catacomb.
+ * This file is part of secnet.
+ * See README for full list of copyright holders.
+ *
+ * secnet is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version d of the License, or
+ * (at your option) any later version.
+ *
+ * secnet is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * version 3 along with secnet; if not, see
+ * https://www.gnu.org/licenses/gpl.html.
+ *
+ * This file was originally part of Catacomb, but has been automatically
+ * modified for incorporation into secnet: see `import-catacomb-crypto'
+ * for details.
  *
  * Catacomb is free software; you can redistribute it and/or modify
  * it under the terms of the GNU Library General Public License as
@@ -82,13 +65,7 @@ typedef union {
   int32 p28[16];
 } fgoldi;
 
-#if !defined(FGOLDI_IMPL) && defined(HAVE_INT64)
-#  define FGOLDI_IMPL 28
-#endif
-
-#ifndef FGOLDI_IMPL
-#  define FGOLDI_IMPL 12
-#endif
+  typedef int32 fgoldi_piece;
 
 /*----- Functions provided ------------------------------------------------*/
 
@@ -162,6 +139,52 @@ extern void fgoldi_add(fgoldi */*z*/,
 extern void fgoldi_sub(fgoldi */*z*/,
 		       const fgoldi */*x*/, const fgoldi */*y*/);
 
+/* --- @fgoldi_neg@ --- *
+ *
+ * Arguments:	@fgoldi *z@ = where to put the result (may alias @x@)
+ *		@const fgoldi *x@ = an operand
+ *
+ * Returns:	---
+ *
+ * Use:		Set @z = -x@.
+ */
+
+extern void fgoldi_neg(fgoldi */*z*/, const fgoldi */*x*/);
+
+/* --- @fgoldi_pick2@ --- *
+ *
+ * Arguments:	@fgoldi *z@ = where to put the result (may alias @x@ or @y@)
+ *		@const fgoldi *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 fgoldi_pick2(fgoldi */*z*/,
+			 const fgoldi */*x*/, const fgoldi */*y*/,
+			 uint32 /*m*/);
+
+/* --- @fgoldi_pickn@ --- *
+ *
+ * Arguments:	@fgoldi *z@ = where to put the result
+ *		@const fgoldi *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 fgoldi_pickn(fgoldi */*z*/,
+			 const fgoldi */*v*/, size_t /*n*/, size_t /*i*/);
+
 /* --- @fgoldi_condswap@ --- *
  *
  * Arguments:	@fgoldi *x, *y@ = two operands
@@ -176,6 +199,21 @@ extern void fgoldi_sub(fgoldi */*z*/,
 
 extern void fgoldi_condswap(fgoldi */*x*/, fgoldi */*y*/, uint32 /*m*/);
 
+/* --- @fgoldi_condneg@ --- *
+ *
+ * Arguments:	@fgoldi *z@ = where to put the result (may alias @x@)
+ *		@const fgoldi *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 fgoldi_condneg(fgoldi */*z*/, const fgoldi */*x*/, uint32 /*m*/);
+
 /* --- @fgoldi_mulconst@ --- *
  *
  * Arguments:	@fgoldi *z@ = where to put the result (may alias @x@)
@@ -228,6 +266,22 @@ extern void fgoldi_sqr(fgoldi */*z*/, const fgoldi */*x*/);
 
 extern void fgoldi_inv(fgoldi */*z*/, const fgoldi */*x*/);
 
+/* --- @fgoldi_quosqrt@ --- *
+ *
+ * Arguments:	@fgoldi *z@ = where to put the result (may alias @x@ or @y@)
+ *		@const fgoldi *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 fgoldi_quosqrt(fgoldi */*z*/,
+			  const fgoldi */*x*/, const fgoldi */*y*/);
+
 /*----- That's all, folks -------------------------------------------------*/
 
 #ifdef __cplusplus