Compiling for RISCY without FP?

[LarsKeuninckx]

I successfully got Pulpissimo with RISCY working on the Digilent ARTY-A7-100T board, running the "Hello" example using the pulp-SDK. Yeeey!

I configured RISCY to not use a floating point unit, by setting:

Code:

localparam USE_FPU  = 0;

in xilinx_pulpissimo.v.

However, the gcc commands of the "Hello" example, following "make clean all", contain:

Code:

... -march=rv32imfcxpulpv2 -mfdiv ...

So the questions are: 

• Does this mean floating point instructions are potentially still being generated?
  

• If so, how do I make the toolchain aware that RISCY was configured without FP unit?
  

Additional info: the toolchain was setup using the instructions at https://github.com/pulp-platform/pulp-ri...ation-pulp.


Thanks!

[bluewww]

Yes, the "f" in "-march" means the compiler will emit floating point instructions. If you don't have the "f", but still use floats in your code then software emulation routines will be inserted for you.

To override the default "-march" flags, you can set PULP_FC_ARCH_CFLAGS in your application's Makefile.

[LarsKeuninckx]

Thanks Bluewww,

so for RI5CY without FP that should be this:

PULP_FC_ARCH_CFLAGS = -march=rv32imcxpulpv2



EDIT : just tried that and it compiles and works!