Re: [Jamvm-general] Data Alignment of a double precision float
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Re: [Jamvm-general] Data Alignment of a double precision float
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From: Robert L. <rob...@gm...> - 2009-03-06 14:39:50
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Hi Donald,
Yes, you can provide the login details. However, I can't promise when
or how much time I will be able to spend on it, as I've started a new
job, and currently have very little free time :(
Rob.
2009/3/6 Donald Gim <don...@gm...>:
> Hi Rob,
>
> We tested JamVM 1.5.2 on our MIPS box.
> But it seems that we still have the trouble on 8-byte-unaligned double data.
> It could not be from your JVM.
> If you're still interested in any testing on the MIPS box,
> we're ready to provide a login onto our development server.
> You can access to the MIPS box from the server.
>
> Donald
>
> 2008/12/13 Robert Lougher <rob...@gm...>
> - Show quoted text -
>>
>> Hi Donald,
>>
>> Yes, there may be other more subtle ones lurking in the code. I'm
>> quite keen to fix the "8-byte aligned double" issues once and for all.
>> I've actually realised I do have a machine -- an old UltraSparc IIi
>> -- although it's 64-bit, Ubuntu has a 32-bit userland (the problem
>> only occurs on 32-bit machines) but I need to port JamVM to Sparc
>> first. Alternatively, is it possible to provide a login onto your
>> MIPS box?
>>
>> Rob.
>>
>> but it's difficult without a machine that requires it.
>>
>> 2008/12/12 Donald Gim <don...@gm...>:
>> > Thank you for your reply.
>> >
>> > I tried the recent Jamvm with the recent Classpath CVS version.
>> > I still got the Bus Error from the 'double' data alignment.
>> >
>> > The following code is from src/jni:798.
>> > This has the possibility of causing the alignment exception if
>> > 'native_type' is 'double'.
>> > Actually I ran into the issue at this part.
>> >
>> > #define GET_STATIC_FIELD(type, native_type) \
>> > native_type Jam_GetStatic##type##Field(JNIEnv *env, jclass clazz,
>> > jfieldID fieldID) { \
>> > FieldBlock *fb = (FieldBlock *) fieldID; \
>> > return *(native_type *)&fb->static_value; \
>> > }
>> >
>> > So I did a little tweak on the FieldBlock structure like below.
>> > And I could avoid the SIGBUS at this part.
>> > But I still got the Bus Error messages from other places.
>> > Should I continue tracing the source?
>> > The case below may be simple. But I guess there could be codes which
>> > are difficult to modify structurally.
>> > Please give me any hints...
>> >
>> > thanks,
>> > ddgim
>> >
>> > 512 typedef struct fieldblock {
>> > 513 double dummy_align; <=== added
>> > 514 Class *class;
>> > 515 char *name;
>> > 516 char *type;
>> > 517 char *signature;
>> > 518 u2 access_flags;
>> > 519 u2 constant;
>> > 520 int dummy_pad; <=== added
>> > 521 uintptr_t static_value;
>> > 522 u4 offset;
>> > 523 AnnotationData *annotations;
>> > 524 } FieldBlock;
>> >
>> >
>> > 2008/12/12, Robert Lougher <rob...@gm...>:
>> >> P.S. When using source from CVS, you need to run autogen.sh (in the
>> >> top level) to generate all the configure stuff. You can give your
>> >> configure arguments to autogen.sh, which will run configure for you,
>> >> once all the autconf/automake/libtool stuff has been done.
>> >>
>> >> Rob.
>> >>
>> >> 2008/12/11 Robert Lougher <rob...@gm...>:
>> >>> Hi Donald,
>> >>>
>> >>> 2008/12/11 Donald Gim <don...@gm...>:
>> >>>> Hello,
>> >>>>
>> >>>> I'm working on a MIPS SoC with the floating-point coprocessor.
>> >>>> It requires an 8-byte aligned address to access to 'double' data.
>> >>>> Jamvm includes codes which try to access 'double' data without
>> >>>> 8-byte-aligned addresses.
>> >>>> They cause 'Bus Error' on the SoC.
>> >>>> How could I work around it.
>> >>>>
>> >>>
>> >>> Try the latest development version from CVS. Instructions to get it
>> >>> are
>> >>> here:
>> >>>
>> >>> http://developer.berlios.de/cvs/?group_id=6545
>> >>>
>> >>> There's been quite a bit of alignment work since 1.5.1, and doubles
>> >>> should now always be 8-byte aligned. However, I can't guarantee it
>> >>> will work, as I don't have a machine which requires it...
>> >>>
>> >>> Rob.
>> >>>
>> >>>> Thanks,
>> >>>> ddgim
>> >>>>
>> >>>>
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>> >>>> _______________________________________________
>> >>>> Jamvm-general mailing list
>> >>>> Jam...@li...
>> >>>> https://lists.sourceforge.net/lists/listinfo/jamvm-general
>> >>>>
>> >>>
>> >>
>> >
>
>
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