www.usr.com/support/gpl/USR9107_release.1.4.tar.gz

[bcm963xx.git] / userapps / opensource / sshd / libtommath / bn_mp_mul_2d.c

diff --git a/userapps/opensource/sshd/libtommath/bn_mp_mul_2d.c b/userapps/opensource/sshd/libtommath/bn_mp_mul_2d.c
index ded3a3c..04cb8dd 100755 (executable)
--- a/userapps/opensource/sshd/libtommath/bn_mp_mul_2d.c
+++ b/userapps/opensource/sshd/libtommath/bn_mp_mul_2d.c
@@ -1,9 +1,11 @@
+#include <tommath.h>
+#ifdef BN_MP_MUL_2D_C
 /* LibTomMath, multiple-precision integer library -- Tom St Denis
  *
- * LibTomMath is library that provides for multiple-precision
+ * LibTomMath is a library that provides multiple-precision
  * integer arithmetic as well as number theoretic functionality.
  *
- * The library is designed directly after the MPI library by
+ * The library was designed directly after the MPI library by
  * Michael Fromberger but has been written from scratch with
  * additional optimizations in place.
  *
@@ -12,17 +14,9 @@
  *
  * Tom St Denis, tomstdenis@iahu.ca, http://math.libtomcrypt.org
  */
-#include <tommath.h>
-
-/* NOTE:  This routine requires updating.  For instance the c->used = c->alloc bit
-   is wrong.  We should just shift c->used digits then set the carry as c->dp[c->used] = carry
- 
-   To be fixed for LTM 0.18
- */
 
 /* shift left by a certain bit count */
-int
-mp_mul_2d (mp_int * a, int b, mp_int * c)
+int mp_mul_2d (mp_int * a, int b, mp_int * c)
 {
   mp_digit d;
   int      res;
@@ -34,8 +28,8 @@ mp_mul_2d (mp_int * a, int b, mp_int * c)
      }
   }
 
-  if (c->alloc < (int)(c->used + b/DIGIT_BIT + 2)) {
-     if ((res = mp_grow (c, c->used + b / DIGIT_BIT + 2)) != MP_OKAY) {
+  if (c->alloc < (int)(c->used + b/DIGIT_BIT + 1)) {
+     if ((res = mp_grow (c, c->used + b / DIGIT_BIT + 1)) != MP_OKAY) {
        return res;
      }
   }
@@ -46,17 +40,19 @@ mp_mul_2d (mp_int * a, int b, mp_int * c)
       return res;
     }
   }
-  c->used = c->alloc;
 
   /* shift any bit count < DIGIT_BIT */
   d = (mp_digit) (b % DIGIT_BIT);
   if (d != 0) {
-    register mp_digit *tmpc, mask, r, rr;
+    register mp_digit *tmpc, shift, mask, r, rr;
     register int x;
 
     /* bitmask for carries */
     mask = (((mp_digit)1) << d) - 1;
 
+    /* shift for msbs */
+    shift = DIGIT_BIT - d;
+
     /* alias */
     tmpc = c->dp;
 
@@ -64,7 +60,7 @@ mp_mul_2d (mp_int * a, int b, mp_int * c)
     r    = 0;
     for (x = 0; x < c->used; x++) {
       /* get the higher bits of the current word */
-      rr = (*tmpc >> (DIGIT_BIT - d)) & mask;
+      rr = (*tmpc >> shift) & mask;
 
       /* shift the current word and OR in the carry */
       *tmpc = ((*tmpc << d) | r) & MP_MASK;
@@ -73,7 +69,13 @@ mp_mul_2d (mp_int * a, int b, mp_int * c)
       /* set the carry to the carry bits of the current word */
       r = rr;
     }
+    
+    /* set final carry */
+    if (r != 0) {
+       c->dp[(c->used)++] = r;
+    }
   }
   mp_clamp (c);
   return MP_OKAY;
 }
+#endif