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authorMatt Johnston <matt@ucc.asn.au>2006-03-08 13:16:18 +0000
committerMatt Johnston <matt@ucc.asn.au>2006-03-08 13:16:18 +0000
commit1c5fda515f96c27d4e3b732d887f418453f1cb14 (patch)
treebf90196389a9618de48c5acb5ce1d056aa347ce0 /bn_mp_get_int.c
Import of libtommath 0.35
From ltm-0.35.tar.bz2 SHA1 of 3f193dbae9351e92d02530994fa18236f7fde01c --HG-- branch : libtommath-orig extra : convert_revision : 2b4b13ac88b2a81e5c86ba868c92c6a452630e02
Diffstat (limited to 'bn_mp_get_int.c')
-rw-r--r--bn_mp_get_int.c41
1 files changed, 41 insertions, 0 deletions
diff --git a/bn_mp_get_int.c b/bn_mp_get_int.c
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--- /dev/null
+++ b/bn_mp_get_int.c
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+#include <tommath.h>
+#ifdef BN_MP_GET_INT_C
+/* LibTomMath, multiple-precision integer library -- Tom St Denis
+ *
+ * LibTomMath is a library that provides multiple-precision
+ * integer arithmetic as well as number theoretic functionality.
+ *
+ * The library was designed directly after the MPI library by
+ * Michael Fromberger but has been written from scratch with
+ * additional optimizations in place.
+ *
+ * The library is free for all purposes without any express
+ * guarantee it works.
+ *
+ * Tom St Denis, tomstdenis@iahu.ca, http://math.libtomcrypt.org
+ */
+
+/* get the lower 32-bits of an mp_int */
+unsigned long mp_get_int(mp_int * a)
+{
+ int i;
+ unsigned long res;
+
+ if (a->used == 0) {
+ return 0;
+ }
+
+ /* get number of digits of the lsb we have to read */
+ i = MIN(a->used,(int)((sizeof(unsigned long)*CHAR_BIT+DIGIT_BIT-1)/DIGIT_BIT))-1;
+
+ /* get most significant digit of result */
+ res = DIGIT(a,i);
+
+ while (--i >= 0) {
+ res = (res << DIGIT_BIT) | DIGIT(a,i);
+ }
+
+ /* force result to 32-bits always so it is consistent on non 32-bit platforms */
+ return res & 0xFFFFFFFFUL;
+}
+#endif