[PATCH 3/3] rtems: Constify rtems_task_wake_when()

[Sebastian Huber]

On 11/05/2021 22:07, Gedare Bloom wrote:
> I'm not a big fan of the way this has been implemented. It exposes an
> internal implementation detail (how you mask the ticks). I don't quite
> see why it is being done.

[...]
>> diff --git a/cpukit/rtems/src/taskwakewhen.c b/cpukit/rtems/src/taskwakewhen.c
>> index a25204ad01..110debfec2 100644
>> --- a/cpukit/rtems/src/taskwakewhen.c
>> +++ b/cpukit/rtems/src/taskwakewhen.c
>> @@ -27,7 +27,7 @@
>>   #include <rtems/score/watchdogimpl.h>
>>
>>   rtems_status_code rtems_task_wake_when(
>> -  rtems_time_of_day *time_buffer
>> +  const rtems_time_of_day *time_buffer
>>   )
>>   {
>>     uint32_t          seconds;
>> @@ -38,11 +38,7 @@ rtems_status_code rtems_task_wake_when(
>>     if ( !_TOD_Is_set() )
>>       return RTEMS_NOT_DEFINED;
>>
>> -  if ( !time_buffer )
>> -    return RTEMS_INVALID_ADDRESS;
>> -
>> -  time_buffer->ticks = 0;
>> -  status = _TOD_Validate( time_buffer );
>> +  status = _TOD_Validate( time_buffer, 0 );

The reason for the ticks mask is above. In rtems_task_wake_when(), the 
ticks member is ignored. Before the change you had a double check for 
time_buffer == NULL (one in rtems_task_wake_when() and one in 
_TOD_Validate()). Ignoring the ticks was done with a write to the 
structure. Now the structure is no longer modified.  Using a mask 
parameter is quite efficient. You just have to load an immediate value 
and there are no additional branches in _TOD_Validate(). I can add this 
text to the commit message.

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