Function reg_get_value 

pub unsafe extern "C" fn reg_get_value(
    reg: reg_id_t,
    mc: *mut dr_mcontext_t,
) -> reg_t

Returns the value of the register \p reg, selected from the passed-in register values. Supports only general-purpose registers. \p mc->flags must include DR_MC_CONTROL and DR_MC_INTEGER.