There are several compiler helper functions that are used by the compiler to handle operations that do not have a short machine code equivalent. For example, integer divide uses a helper function because there is no divide instruction in the ARM and Thumb instruction set.

Integer divide, and all the floating-point functions, require __rt_raise() to handle math errors. Re-implementing __rt_raise() enables all the math helper functions, and it avoids having to link in all the signal-handling library code.