One important point to note about the preceding steps is that they must all be carried out before the C library's floating-point initialization takes place. This is done by the library routine _fp_init().

The easiest way to do this is to write a simple function that calls the required routines from sections 3.1-3.5 which armlink can automatically cause to be executed directly before _fp_init() is executed. This is done using the $Sub$$ and $Super$$ functionality, which is detailed in the RVDS Linker and Utilities Guide. The following C code example shows how this can be done:

#ifdef __cplusplus
    #define EXTERN_C extern "C"
#else
    #define EXTERN_C extern
#endif

#ifdef SETUP_UNDEF_STACK
        EXTERN_C void Setup_Undef_Stack (void);
#endif
#ifdef PATCH_UNDEF_VECTOR
        EXTERN_C void Install_VFPHandler (void);
#endif
#ifdef INIT_CM10rev0_VFP
        EXTERN_C void CM_VFP_enable (void);
#endif

EXTERN_C void Enable_VFP (void);
EXTERN_C void $Super$$_fp_init(void);

// Call $Sub$$_fp_init() in place of original _fp_init()
EXTERN_C void $Sub$$_fp_init(void)   
{

#ifdef PATCH_UNDEF_VECTOR
        Install_VFPHandler();
#endif
#ifdef SETUP_UNDEF_STACK
        Setup_Undef_Stack();
#endif
#ifdef INIT_CM10rev0_VFP
        CM_VFP_enable();
#endif
        Enable_VFP();
        $Super$$_fp_init();   // Call original _fp_init()
}