Function riscv_rt::start_trap_rust

#[link_section = ".trap.rust"]
#[export_name = "_start_trap_rust"]
pub extern "C" fn start_trap_rust()

Trap entry point rust (_start_trap_rust)

mcause is read to determine the cause of the trap. XLEN-1 bit indicates if it's an interrupt or an exception. The result is converted to an element of the Interrupt or Exception enum and passed to handle_interrupt or handle_exception.