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

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

diff --git a/userapps/opensource/sshd/libtommath/bn_mp_lcm.c b/userapps/opensource/sshd/libtommath/bn_mp_lcm.c
index 75b5829..8e3a759 100755 (executable)
--- a/userapps/opensource/sshd/libtommath/bn_mp_lcm.c
+++ b/userapps/opensource/sshd/libtommath/bn_mp_lcm.c
@@ -1,9 +1,11 @@
+#include <tommath.h>
+#ifdef BN_MP_LCM_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.
  *
@@ -12,31 +14,43 @@
  *
  * Tom St Denis, tomstdenis@iahu.ca, http://math.libtomcrypt.org
  */
-#include <tommath.h>
 
-/* computes least common multiple as a*b/(a, b) */
-int
-mp_lcm (mp_int * a, mp_int * b, mp_int * c)
+/* computes least common multiple as |a*b|/(a, b) */
+int mp_lcm (mp_int * a, mp_int * b, mp_int * c)
 {
   int     res;
-  mp_int  t;
+  mp_int  t1, t2;
 
 
-  if ((res = mp_init (&t)) != MP_OKAY) {
+  if ((res = mp_init_multi (&t1, &t2, NULL)) != MP_OKAY) {
     return res;
   }
 
-  if ((res = mp_mul (a, b, &t)) != MP_OKAY) {
-    mp_clear (&t);
-    return res;
+  /* t1 = get the GCD of the two inputs */
+  if ((res = mp_gcd (a, b, &t1)) != MP_OKAY) {
+    goto LBL_T;
   }
 
-  if ((res = mp_gcd (a, b, c)) != MP_OKAY) {
-    mp_clear (&t);
-    return res;
+  /* divide the smallest by the GCD */
+  if (mp_cmp_mag(a, b) == MP_LT) {
+     /* store quotient in t2 such that t2 * b is the LCM */
+     if ((res = mp_div(a, &t1, &t2, NULL)) != MP_OKAY) {
+        goto LBL_T;
+     }
+     res = mp_mul(b, &t2, c);
+  } else {
+     /* store quotient in t2 such that t2 * a is the LCM */
+     if ((res = mp_div(b, &t1, &t2, NULL)) != MP_OKAY) {
+        goto LBL_T;
+     }
+     res = mp_mul(a, &t2, c);
   }
 
-  res = mp_div (&t, c, c, NULL);
-  mp_clear (&t);
+  /* fix the sign to positive */
+  c->sign = MP_ZPOS;
+
+LBL_T:
+  mp_clear_multi (&t1, &t2, NULL);
   return res;
 }
+#endif