Adding upstream version 2:4.20.0+dfsg.upstream/2%4.20.0+dfsg

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 37 insertions, 0 deletions

diff --git a/third_party/heimdal/lib/hcrypto/libtommath/bn_mp_cnt_lsb.c b/third_party/heimdal/lib/hcrypto/libtommath/bn_mp_cnt_lsb.c
new file mode 100644
index 0000000..4b2d206
--- /dev/null
+++ b/third_party/heimdal/lib/hcrypto/libtommath/bn_mp_cnt_lsb.c
@@ -0,0 +1,37 @@
+#include "tommath_private.h"
+#ifdef BN_MP_CNT_LSB_C
+/* LibTomMath, multiple-precision integer library -- Tom St Denis */
+/* SPDX-License-Identifier: Unlicense */
+
+static const int lnz[16] = {
+   4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0
+};
+
+/* Counts the number of lsbs which are zero before the first zero bit */
+int mp_cnt_lsb(const mp_int *a)
+{
+   int x;
+   mp_digit q, qq;
+
+   /* easy out */
+   if (MP_IS_ZERO(a)) {
+      return 0;
+   }
+
+   /* scan lower digits until non-zero */
+   for (x = 0; (x < a->used) && (a->dp[x] == 0u); x++) {}
+   q = a->dp[x];
+   x *= MP_DIGIT_BIT;
+
+   /* now scan this digit until a 1 is found */
+   if ((q & 1u) == 0u) {
+      do {
+         qq  = q & 15u;
+         x  += lnz[qq];
+         q >>= 4;
+      } while (qq == 0u);
+   }
+   return x;
+}
+
+#endif