- Define header functions for Critical Section HAL API
- hal_critical_section_enter()
- hal_critical_section_exit()
- Add weak default implementation for HAL API. The default implementation
matches the previous behaviour stored in mbed_critical:
- The first call to enter a critical section stores the state of interrupts
before disabling and each successive call re-disables interrupts.
- The last call (non-nested) will restore the IRQ state that was set on the
enter to the critical section. Nested calls are ignored.
- Add function 'core_util_in_critical_section' to User facing API to determine
if the program is currently in a critical section, instead of depending on
'core_util_interrupts_enabled'.
Add a note to each CAS making explicit that the functions are strong.
Minor wording change to expectedCurrentValue - use of "still updated"
about the failure case suggested that it might be written to on success.
For some uses it's critically important that expectedCurrentValue only
be written on failure, so change wording to "instead updated".
Steven Cartmell
Kevin Bracey
Senthil Ramakrishnan
Russ Butler
Sam Grove
Christopher Haster