X-Git-Url: https://git.distorted.org.uk/~mdw/secnet/blobdiff_plain/b7a5ecfcbac18c56d0b044975f6ed6835dd86ab4..0bcb8184cfce875a4dde57621139dd44c433f3a5:/qfarith.h

diff --git a/qfarith.h b/qfarith.h
index abcd293..fcedf3e 100644
--- a/qfarith.h
+++ b/qfarith.h
@@ -1,3 +1,40 @@
+/*
+ * qfarith.h: utilities for quick field arithmetic
+ */
+/*
+ * 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 modified for Secnet (2017-04-30):
+ *
+ *   * Use `fake-mLib-bits.h' in place of the real <mLib/bits.h>.
+ *
+ *   * Use C99 signed integer types instead of our own local probing.
+ *
+ *   * Remove the support for non-two's-complement targets.
+ *
+ * The file's original comment headers are preserved below.
+ */
 /* -*-c-*-
  *
  * Utilities for quick field arithmetic
@@ -35,35 +72,15 @@
 /*----- Header files ------------------------------------------------------*/
 
 #include <limits.h>
+#include <stdint.h>
 
-#include <mLib/bits.h>
+#include "fake-mLib-bits.h"
 
 /*----- Signed integer types ----------------------------------------------*/
 
-/* See if we can find a suitable 64-bit or wider type.  Don't bother if we
- * don't have a corresponding unsigned type, because we really need both.
- */
-#ifdef HAVE_UINT64
-#  if INT_MAX >> 31 == 0xffffffff
-#    define HAVE_INT64
-     typedef int int64;
-#  elif LONG_MAX >> 31 == 0xffffffff
-#    define HAVE_INT64
-     typedef long int64;
-#  elif defined(LLONG_MAX)
-#    define HAVE_INT64
-     MLIB_BITS_EXTENSION typedef long long int64;
-#  endif
-#endif
-
-/* Choose suitable 32- and 16-bit types. */
-#if INT_MAX >= 0x7fffffff
-   typedef int int32;
-#else
-   typedef long int32;
-#endif
-
-typedef short int16;
+typedef int_fast32_t int32;
+typedef int_fast64_t int64;
+#define HAVE_INT64 1
 
 /*----- General bit-hacking utilities -------------------------------------*/
 
@@ -117,42 +134,7 @@ typedef short int16;
 # define CONDSWAP(x, y, m)						\
     do { mask32 t_ = ((x) ^ (y))&(m); (x) ^= t_; (y) ^= t_; } while (0)
 #else
-
-  /* We don't have two's complement arithmetic.  We can't use bithacking at
-   * all: if we try to hack on the bits of signed numbers we'll come unstuck
-   * when we hit the other representation of zero; and if we switch to
-   * unsigned arithmetic then we'll have overflow when we try to convert a
-   * negative number back.  So fall back to simple arithmetic.
-   */
-  typedef uint32 mask32;
-
-  /* Convert an unsigned mask M into a `mask32'.  Our masks are unsigned, so
-   * this does nothing.
-   */
-# define FIX_MASK32(m) ((mask32)(m))
-
-  /* If Z is zero and M has its low 32 bits set, then copy (at least) the low
-   * 32 bits of X to Z; if M is zero, do nothing.  Otherwise, scramble Z
-   * unhelpfully.
-   */
-# define CONDPICK(z, x, m)						\
-    do { (z) += (x)*(int)((unsigned)(m)&1u); } while (0)
-
-  /* If M has its low 32 bits set, then return (at least) the low 32 bits of
-   * X in Z; if M is zero, then return (at least) the low 32 bits of Y in Z.
-   * Otherwise, return an unhelful result.
-   */
-# define PICK2(x, y, m)							\
-    ((x)*(int)((unsigned)(m)&1u) + (y)*(int)(1 - ((unsigned)(m)&1u)))
-
-  /* If M has its low 32 bits set then swap (at least) the low 32 bits of X
-   * and Y; if M is zero, then do nothing.  Otherwise, scramble X and Y
-   * unhelpfully.
-   */
-# define CONDSWAP(x, y, m) do {						\
-    int32 x_ = PICK2((y), (x), (m)), y_ = PICK2((x), (y), (m));		\
-    (x) = x_; (y) = y_;							\
-  } while (0)
+#  error "Targets without two's complement arithmetic aren't supported"
 #endif
 
 /* Return zero if bit 31 of X is clear, or a mask with (at least) the low 32