6.59.17 Other MIPS Built-in Functions

GCC provides other MIPS-specific built-in functions:

void __builtin_mips_cache (int op , const volatile void * addr )
Insert a ‘ cache ’ instruction with operands op and addr . GCC defines the preprocessor macro ___GCC_HAVE_BUILTIN_MIPS_CACHE when this function is available.
unsigned int __builtin_mips_get_fcsr (void)
void __builtin_mips_set_fcsr (unsigned int value )
Get and set the contents of the floating-point control and status register (FPU control register 31). These functions are only available in hard-float code but can be called in both MIPS16 and non-MIPS16 contexts.

__builtin_mips_set_fcsr can be used to change any bit of the register except the condition codes, which GCC assumes are preserved.