[Vm-dev] FFI Testing - Curiouser and curiouser!

[Juan Vuletich]

On 2/15/2019 1:55 PM, ken.dickey at whidbey.com wrote:
>
> On 2019-02-14 16:39, Andres Valloud wrote:
>> Something doesn't look right there.  The test in question appears to
>> be adding all integers from 1 to 9 as floating point numbers, and
>> seems to be expecting the result is 45 as a floating point number.
>> That calculation should need no epsilons, it's lossless in floating
>> point land (under the usual assumptions).  What's going on, exactly?
>>
>
> I am clueless.  Different compiler versions.  Different silocon. All 
> gcc+Linux.  All "git cloned" from same 
> https://github.com/KenDickey/opensmalltalk-vm (cloned from 
> OPenSmalltalk w minor changes).
>
> Vanilla (epsilon-less) test:
>  - Failed on Raspberry Pi 3 (Broadcom aarch64) and older x86_64.
>  - Passed on aarch64 Samsung Chromebook Plus (Rockchip) and LePotato 
> (AMLogic).
> I have stepped through the call to ffiTestDoubles9 with gdb, which 
> returns float(45.) but get lost in the various alloc,copy,shift,mask 
> mechanics as things unwind in the interpreter vm.
>
> It is beyond my poor shrinking brain..
> -KenD

When it fails, what are the 8 bytes you get in gdb? What are the 8 bytes 
you get in Cuis (in the Cuis debugger, at the moment of the failure).

-- 
Juan Vuletich
www.cuis-smalltalk.org
https://github.com/Cuis-Smalltalk/Cuis-Smalltalk-Dev
https://github.com/jvuletich
https://www.linkedin.com/in/juan-vuletich-75611b3
@JuanVuletich