Hi! On Sun, Nov 25, 2018 at 05:36:38PM -0500, Felipe GM wrote: > >On Sun, Nov 25, 2018 at 02:42:10PM -0500, Felipe GM wrote: > >>Currently I am developing for a MPC5777 board, with e200z7 cores. Most > >>of the things are going well, but I am stuck with a problem that is > >>really annoying me already. I am trying to use floating point operations > >>on portions of my code, using the embedded hardware support. My > >>toolchain is GCC 6.3 (powerpc-gcc, although I have tried with 7.3 and > >>8.2 too), for which I am using the following flags: > >*GCC 6 is no longer maintained. GCC 8 powerpc*-* does not support SPE > >anymore (you need to configure for powerpc*-*spe* instead; you > >probably want that for GCC 6 and GCC 7 as well).* > That is why I tried 7.3 and 8.2! Regarding powerpc-*-spe, do you mean to > use a different cross gcc? Or just different compilation flags? It's easiest if you build for target powerpc-eabispe or whatever you have. That will default -mspe etc.; and you may not even be able to switch it on other configurations, at all. > >>|ASFLAGS_BASE =-g -a32 -mbooke -me500 --fatal-warnings ARCH_FLAGS > >>=-mpowerpc-gpopt -mfprnd -misel -m32 -mhard-float-mabi=spe -mmfpgpr > >>-mfloat-gprs=single| > >*-mpowerpc-gpopt, -mfprnd, -mmfpgpr, and -mhard-float do not make > >sense for your target.* > I have used most of them in order to try to solve the issue. One > question here though. When I use -mspe (or something similar, depending > on the gcc version) flag, not always the floating point support is > provided. More than once the linker asked for the unimplemented > functions, similar to what I said before (__divdf3, etc). Your CPU has hardware support for single precision only. You get the soft float support for double precision (like that __divdf3, yes -- anything "df"). This is what -mfloat-gprs=single does :-) You always should link libgcc. This is the default if you link using gcc, but your custom linker scripts may have other plans ;-) Segher
