[kaffe] Bug Report: Large BigIntegers aren't displayed
Alan Eliasen
eliasen at mindspring.com
Mon Apr 19 03:22:19 PDT 2004
I've been happily experimenting with using Kaffe to run my programming
language/calculating tool "Frink" : http://futureboy.homeip.net/frinkdocs/ in
order to get the high-performance integer performance of the GP library, but
I'm having some problems.
I've compiled Kaffe with the GMP libraries on Linux (Red Hat 9).
Engine: Just-in-time v3 Version: 1.1.4 Java Version: 1.1
Note: I compiled GMP with --disable-fft due to known bugs in the FFT
multiplication routines.
When I try to calculate and display large integers (say, large Mersenne
primes, it works up to a point, and then large numbers, say, 2^13466917-1
simply don't get formatted at all by the toString() method. Running the "top"
command shows that nothing's running, no exceptions are thrown, and the
program doesn't continue.
Below is a sample program that illustrates the problem. If you replace the
number 13466917 with a smaller number, it is displayed correctly. This sample
works as expected (although bloody slow (15+ hours ?!) for the toString()
method in Sun's VMs.)
------------------------------------------------------
import java.math.BigInteger;
public class BigIntTest
{
/** This calculates the (previously) largest-known Mersenne Prime,
2^13466917 - 1 */
public static void main(String[] args)
{
System.out.println("Starting");
BigInteger b = new BigInteger("2");
BigInteger p = b.shiftLeft(13466917 - 1);
System.out.println("Exponentiation complete");
p = p.subtract(new BigInteger("1"));
System.out.println("Subtraction complete");
System.out.println(p.toString());
System.out.println("Formatting completed.");
}
}
-------------------------------------------------------------
If anyone has any hints, workarounds, or can simply verify this behavior,
please let me know.
--
Alan Eliasen | "You cannot reason a person out of a
eliasen at mindspring.com | position he did not reason himself
http://futureboy.homeip.net/ | into in the first place."
| --Jonathan Swift
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