[PATCH] 64-bit dtoa - strtod fix

[Christian Thalinger]

We are building a java jit called cacao
(http://www.complang.tuwien.ac.at/java/cacao/) which now uses the gnu
classpath. On our 64-bit ports we had problems with dtoa and strtod
functions. After a long night of debugging, i found the problem: it
seems that in mprec.h

#define MAX_BIGNUM_WDS 32

is too small for some floats. The amount can grow up to 48, as my
debugging showed. On i386 systems where Pack_32 is defined, it seems to
be ok. But Pack_32 does not work on 64-bit systems.

This bug is hit, when you try to execute this small code

class test {
    public static void main(String[] argv) {
        System.out.println(Double.MIN_VALUE);
    }
}

with gij (gcc-3.3.2) on x86_64. Defining

#define MAX_BIGNUM_WDS 64

shows the expected result with our jit. I don't know if 64 is a
reasonable number, but when not packing 32-bit in a long but 16-bit,
twice as much should be ok.

This is also cross-posted to address@hidden

TWISTI

--- classpath-0.07/native/fdlibm/mprec.h        2001-11-05
03:56:47.000000000 +0100
+++ cacaodev/gnuclasspath/native/fdlibm/mprec.h 2004-01-11
17:17:55.000000000 +0100
@@ -295,7 +298,12 @@


#define MAX_BIGNUMS 16
+
+#ifndef Pack_32
+#define MAX_BIGNUM_WDS 64
+#else
#define MAX_BIGNUM_WDS 32
+#endif

struct _Jv_Bigint
{