The CrossWorks tasking library provides functions that lock and unlock the global interrupt enables. These functions can be used (sparingly) to provide a fast mutual exclusion facility for time critical uses.

You can disable interrupts using the ctl_global_interrupts_disable function call.

    int en=ctl_global_interrupts_disable();

This function returns the previous global interrupts enabled state.

You can enable interrupts using the ctl_global_interrupts_enable function call.

    int en=ctl_global_interrupts_enable();

This function returns the previous global interrupts enabled state.

You can restore the previous global interrupts enabled state you the ctl_global_interrupts_set function call.

    int en=ctl_global_interrupts_disable();
    ...
    ctl_set_interrupts(en);

Note that you can call a tasking library function that causes a task switch with global interrupts disabled. The tasking library will ensure that when a task is scheduled that global interrupts are enabled.

You can re-enable global interrupt enables from within an interrupt service routine using the ctl_global_interrupts_re_enable_from_isr function call in order to permit higher priority interrupts to occur. A call to this function must be matched with a call to the ctl_global_interrupts_un_re_enable_from_isr function.

      // code of interrupt service routine
      ....
      ctl_global_interrupts_re_enable_from_isr();
      ....
      // global interrupts are now enabled so another interrupt can be handled.
      ....
      ctl_global_interrupts_un_re_enable_from_isr();
      ....