On Tue, Sep 22, 2015 at 01:43:55PM -0400, David Edelsohn wrote: > On Tue, Sep 22, 2015 at 1:39 PM, Bernhard Schommer > <bernhardschom...@gmail.com> wrote: > > Hi, > > > > if been working with the windriver Diab c compiler for 32bit ppc for and > > encountered an incompatibly with the eabi version of the gcc 4.83. When > > calling functions with more than 8 float arguments the gcc stores the 9th > > float argument (and so on) as a float where as the diab compiler stores the > > argument as a double using 8 byte. > > > > I checked the EABI document and it seems to support the way the diab > > compiler passes the arguments: > > > > "Arguments not otherwise handled above [i.e. not passed in registers] > > are passed in the parameter words of the caller=E2=80=99s stack frame. [...= > > ] > > float, long long (where implemented), and double arguments are > > considered to have 8-byte size and alignment, *with float arguments > > converted to double representation*. " > > > > Does anyone know the reason why the gcc passes the argument as single float? > > Hi, Bernhard > > First, are you certain that you have the final version of the 32 bit > PPC eABI? There were a few versions in circulation. > > Mike may remember the history of this.
Well I worked on it around 1980 or so. I don't remember the details (nor do I have the original manuals I was working from). From this distance, it sure looks like a bug, but I'm not sure whether it should be fixed or grand-fathered in (and updating the stdargs.h support, if this is the offical calling sequence). -- Michael Meissner, IBM IBM, M/S 2506R, 550 King Street, Littleton, MA 01460-6245, USA email: meiss...@linux.vnet.ibm.com, phone: +1 (978) 899-4797
