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-rw-r--r--mpi/mpih-cmp.c53
1 files changed, 53 insertions, 0 deletions
diff --git a/mpi/mpih-cmp.c b/mpi/mpih-cmp.c
new file mode 100644
index 00000000..821c0ce8
--- /dev/null
+++ b/mpi/mpih-cmp.c
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+/* 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;
+}
+