Re: [Sablevm-developer] powerpc port status

[Etienne M. G. <eti...@uq...>]

On Fri, Dec 13, 2002 at 02:46:53PM -0500, David Paul BELANGER wrote:
> 
> Hello,
> 
> There something I don't quite get
> 
> native.c around line 1240:
> 
> Original code (does not work on PPC):
>       case SVM_TYPE_BOOLEAN:
>          params[0].jint = *((jboolean *) &result[0]);
> 
> 
> Could it be simply replaced by (works on PPC):
>   params[0].jint = result[0].jint;
> instead?
> 
> or is the address taken, cast, deference for some reason?  I guess it
> depends on how the data is stored in _svmt_stack_value_union by ffi_call
> and how the union is layed out in memory?


libffi is supposed to be returning a boolean (i.e. "char") value at
the location &result [at least, this is what I understood from the
documentation].  So, *((jboolean *) &result[0]) seems to be "the right
way" to extract the returned boolean value.  Nowhere, in the libffi
doc, have I see any special note about handling sub-32bits values
specially (because of alignment constraints), so I suspect libffi is
buggy.

Etienne

-- 
Etienne M. Gagnon                    http://www.info.uqam.ca/~egagnon/
SableVM:                                       http://www.sablevm.org/
SableCC:                                       http://www.sablecc.org/