initially checkin

mpi/mpih-cmp.c

@@ -0,0 +1,53 @@
+/* mpihelp-sub.c  -  MPI helper functions
+ *	Copyright (c) 1997 by Werner Koch (dd9jn)
+ *
+ * This file is part of G10.
+ *
+ * G10 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 2 of the License, or
+ * (at your option) any later version.
+ *
+ * G10 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, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
+ */
+
+#include <config.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "mpi-internal.h"
+
+/****************
+ * Compare OP1_PTR/OP1_SIZE with OP2_PTR/OP2_SIZE.
+ * There are no restrictions on the relative sizes of
+ * the two arguments.
+ * Return 1 if OP1 > OP2, 0 if they are equal, and -1 if OP1 < OP2.
+ */
+int
+mpihelp_cmp( mpi_ptr_t op1_ptr, mpi_ptr_t op2_ptr, mpi_size_t size )
+{
+    mpi_size_t i;
+    mpi_limb_t op1_word, op2_word;
+
+    for( i = size - 1; i >= 0 ; i--) {
+	op1_word = op1_ptr[i];
+	op2_word = op2_ptr[i];
+	if( op1_word != op2_word )
+	    goto diff;
+    }
+    return 0;
+
+  diff:
+    /* This can *not* be simplified to
+     *	 op2_word - op2_word
+     * since that expression might give signed overflow.  */
+    return (op1_word > op2_word) ? 1 : -1;
+}
+