-mdebug-msim-mfpu-mhard-float-mno-fpu-msoft-float-msoft-float changes the calling convention in the output file;
therefore, it is only useful if you compile all of a program with
this option. In particular, you need to compile libgcc.a, the
library that comes with GCC, with -msoft-float in order for
this to work.
-mcpu=cpu_type‘mcm’ is a synonym of ‘gr5’ present for backward compatibility.
By default (unless configured otherwise), GCC generates code for the GR5 variant of the Visium architecture.
With -mcpu=gr6, GCC generates code for the GR6 variant of the Visium
architecture. The only difference from GR5 code is that the compiler will
generate block move instructions.
-mtune=cpu_type-msv-mode-muser-mode