### changeset 7869:834faf2081b3

8022180: BigInteger Burnikel-Ziegler quotient and remainder calculation assumes quotient parameter is zero Summary: Clear the quotient in divideAndRemainderBurnikelZiegler() if the divisor is larger than the dividend. Reviewed-by: alanb, bpb Contributed-by: Timothy Buktu <tbuktu@hotmail.com>
author bpb Mon, 12 Aug 2013 16:21:10 -0700 26753a05859a 18e15d92610b src/share/classes/java/math/MutableBigInteger.java test/java/math/BigInteger/BigIntegerTest.java 2 files changed, 12 insertions(+), 10 deletions(-) [+]
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line diff
```--- a/src/share/classes/java/math/MutableBigInteger.java	Tue Aug 13 14:18:57 2013 +0100
+++ b/src/share/classes/java/math/MutableBigInteger.java	Mon Aug 12 16:21:10 2013 -0700
@@ -1242,6 +1242,9 @@
int r = intLen;
int s = b.intLen;

+        // Clear the quotient
+        quotient.offset = quotient.intLen = 0;
+
if (r < s) {
return this;
} else {
@@ -1276,7 +1279,6 @@
// do schoolbook division on blocks, dividing 2-block numbers by 1-block numbers
MutableBigInteger qi = new MutableBigInteger();
MutableBigInteger ri;
-            quotient.offset = quotient.intLen = 0;
for (int i=t-2; i > 0; i--) {
// step 8a: compute (qi,ri) such that z=b*qi+ri
ri = z.divide2n1n(bShifted, qi);```
```--- a/test/java/math/BigInteger/BigIntegerTest.java	Tue Aug 13 14:18:57 2013 +0100
+++ b/test/java/math/BigInteger/BigIntegerTest.java	Mon Aug 12 16:21:10 2013 -0700
@@ -74,10 +74,10 @@

static final int ORDER_SMALL = 60;
static final int ORDER_MEDIUM = 100;
-    // #bits for testing Karatsuba and Burnikel-Ziegler
+    // #bits for testing Karatsuba
static final int ORDER_KARATSUBA = 1800;
-    // #bits for testing Toom-Cook
-    static final int ORDER_TOOM_COOK = 3000;
+    // #bits for testing Toom-Cook and Burnikel-Ziegler
+    static final int ORDER_TOOM_COOK = 4000;
// #bits for testing Karatsuba squaring
static final int ORDER_KARATSUBA_SQUARE = 3200;
// #bits for testing Toom-Cook squaring
@@ -964,12 +964,12 @@
nextProbablePrime();

arithmetic(order1);   // small numbers
-        arithmetic(order3);   // Karatsuba / Burnikel-Ziegler range
-        arithmetic(order4);   // Toom-Cook range
+        arithmetic(order3);   // Karatsuba range
+        arithmetic(order4);   // Toom-Cook / Burnikel-Ziegler range

divideAndRemainder(order1);   // small numbers
-        divideAndRemainder(order3);   // Karatsuba / Burnikel-Ziegler range
-        divideAndRemainder(order4);   // Toom-Cook range
+        divideAndRemainder(order3);   // Karatsuba range
+        divideAndRemainder(order4);   // Toom-Cook / Burnikel-Ziegler range

pow(order1);
pow(order3);
@@ -989,8 +989,8 @@
byteArrayConv(order1);

modInv(order1);   // small numbers
-        modInv(order3);   // Karatsuba / Burnikel-Ziegler range
-        modInv(order4);   // Toom-Cook range
+        modInv(order3);   // Karatsuba range
+        modInv(order4);   // Toom-Cook / Burnikel-Ziegler range

modExp(order1, order2);
modExp2(order1);```