Using and Porting GNU CC
-m' options are defined for the DEC Alpha implementations:
-msoft-floatis specified, functions in `
libgcc1.c' will be used to perform floating-point operations. Unless they are replaced by routines that emulate the floating-point operations, or compiled in such a way as to call such emulations routines, these routines will issue floating-point operations. If you are compiling for an Alpha without floating-point operations, you must ensure that the library is built so as not to call them.
Note that Alpha implementations without floating-point operations are required to have floating-point registers.
-msoft-float. If the floating-point register set is not used, floating point operands are passed in integer registers as if they were integers and floating-point results are passed in $0 instead of $f0. This is a non-standard calling sequence, so any function with a floating-point argument or return value called by code compiled with
-mno-fp-regsmust also be compiled with that option.
A typical use of this option is building a kernel that does not use, and hence need not save and restore, any floating-point registers.