src/java.base/share/classes/java/math/MutableBigInteger.java

rev 12150 : 8046943: Leverage CPU Instructions for GHASH and RSA
Summary: Add montgomeryMultiply intrinsics
Reviewed-by: kvn

*** 2063,2072 ****
--- 2063,2087 ----
          t *= 2 - val*t;
          return t;
      }
  
      /**
+      * Returns the multiplicative inverse of val mod 2^64.  Assumes val is odd.
+      */
+     static long inverseMod64(long val) {
+         // Newton's iteration!
+         long t = val;
+         t *= 2 - val*t;
+         t *= 2 - val*t;
+         t *= 2 - val*t;
+         t *= 2 - val*t;
+         t *= 2 - val*t;
+         assert(t * val == 1);
+         return t;
+     }
+ 
+     /**
       * Calculate the multiplicative inverse of 2^k mod mod, where mod is odd.
       */
      static MutableBigInteger modInverseBP2(MutableBigInteger mod, int k) {
          // Copy the mod to protect original
          return fixup(new MutableBigInteger(1), new MutableBigInteger(mod), k);