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authorKevin B Kenny <kennykb@acm.org>2005-01-19 22:41:26 (GMT)
committerKevin B Kenny <kennykb@acm.org>2005-01-19 22:41:26 (GMT)
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parentb23d942a1e86ddee18c2309afd7fa7e9afa79ef8 (diff)
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Import of libtommath 0.33
Diffstat (limited to 'libtommath/bn_mp_set_int.c')
-rw-r--r--libtommath/bn_mp_set_int.c44
1 files changed, 44 insertions, 0 deletions
diff --git a/libtommath/bn_mp_set_int.c b/libtommath/bn_mp_set_int.c
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+++ b/libtommath/bn_mp_set_int.c
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+#include <tommath.h>
+#ifdef BN_MP_SET_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
+ */
+
+/* set a 32-bit const */
+int mp_set_int (mp_int * a, unsigned long b)
+{
+ int x, res;
+
+ mp_zero (a);
+
+ /* set four bits at a time */
+ for (x = 0; x < 8; x++) {
+ /* shift the number up four bits */
+ if ((res = mp_mul_2d (a, 4, a)) != MP_OKAY) {
+ return res;
+ }
+
+ /* OR in the top four bits of the source */
+ a->dp[0] |= (b >> 28) & 15;
+
+ /* shift the source up to the next four bits */
+ b <<= 4;
+
+ /* ensure that digits are not clamped off */
+ a->used += 1;
+ }
+ mp_clamp (a);
+ return MP_OKAY;
+}
+#endif