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Fix nasa#1051, use OSAL time conversion/access methods
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Instead of accessing OS_time_t values directly, use the
OSAL-provided conversion and access methods.  This provides
independence/abstraction from the specific OS_time_t
definition and allows OSAL to transition to a 64 bit value.
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@jphickey
jphickey committed Jan 4, 2021
1 parent 56397a3 commit 119e3e6
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Showing 5 changed files with 30 additions and 147 deletions.
17 changes: 2 additions & 15 deletions fsw/cfe-core/src/es/cfe_es_backgroundtask.c
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Original file line number Diff line number Diff line change
Expand Up @@ -136,25 +136,12 @@ void CFE_ES_BackgroundTask(void)
{
/*
* compute the elapsed time (difference) between last
* execution and now, in microseconds.
*
* Note this calculation is done as a uint32 which will overflow
* after about 35 minutes, but the max delays ensure that this
* executes at least every few seconds, so that should never happen.
* execution and now, in milliseconds.
*/
CFE_PSP_GetTime(&CurrTime);
ElapsedTime = 1000000 * (CurrTime.seconds - LastTime.seconds);
ElapsedTime += CurrTime.microsecs;
ElapsedTime -= LastTime.microsecs;
ElapsedTime = OS_TimeGetTotalMilliseconds(OS_TimeSubtract(CurrTime, LastTime));
LastTime = CurrTime;

/*
* convert to milliseconds.
* we do not really need high precision
* for background task timings
*/
ElapsedTime /= 1000;

NextDelay = CFE_ES_BACKGROUND_MAX_IDLE_DELAY; /* default; will be adjusted based on active jobs */
JobPtr = CFE_ES_BACKGROUND_JOB_TABLE;
JobTotal = CFE_ES_BACKGROUND_NUM_JOBS;
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100 changes: 16 additions & 84 deletions fsw/cfe-core/src/time/cfe_time_api.c
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Original file line number Diff line number Diff line change
Expand Up @@ -489,57 +489,16 @@ CFE_TIME_Compare_t CFE_TIME_Compare(CFE_TIME_SysTime_t TimeA, CFE_TIME_SysTime_
*/
uint32 CFE_TIME_Sub2MicroSecs(uint32 SubSeconds)
{
uint32 MicroSeconds;

/* 0xffffdf00 subseconds = 999999 microseconds, so anything greater
* than that we set to 999999 microseconds, so it doesn't get to
* a million microseconds */

if (SubSeconds > 0xffffdf00)
{
MicroSeconds = 999999;
}
else
{
/*
** Convert a 1/2^32 clock tick count to a microseconds count
**
** Conversion factor is ( ( 2 ** -32 ) / ( 10 ** -6 ) ).
**
** Logic is as follows:
** x * ( ( 2 ** -32 ) / ( 10 ** -6 ) )
** = x * ( ( 10 ** 6 ) / ( 2 ** 32 ) )
** = x * ( ( 5 ** 6 ) ( 2 ** 6 ) / ( 2 ** 26 ) ( 2 ** 6) )
** = x * ( ( 5 ** 6 ) / ( 2 ** 26 ) )
** = x * ( ( 5 ** 3 ) ( 5 ** 3 ) / ( 2 ** 7 ) ( 2 ** 7 ) (2 ** 12) )
**
** C code equivalent:
** = ( ( ( ( ( x >> 7) * 125) >> 7) * 125) >> 12 )
*/

MicroSeconds = (((((SubSeconds >> 7) * 125) >> 7) * 125) >> 12);

OS_time_t tm;

/* if the Subseconds % 0x4000000 != 0 then we will need to
* add 1 to the result. the & is a faster way of doing the % */
if ((SubSeconds & 0x3ffffff) != 0)
{
MicroSeconds++;
}

/* In the Micro2SubSecs conversion, we added an extra anomaly
* to get the subseconds to bump up against the end point,
* 0xFFFFF000. This must be accounted for here. Since we bumped
* at the half way mark, we must "unbump" at the same mark
*/
if (MicroSeconds > 500000)
{
MicroSeconds --;
}

} /* end else */

return(MicroSeconds);
/*
** Convert using the OSAL method. Note that there
** is no range check here because any uint32 value is valid,
** and OSAL will handle and properly convert any input.
*/
tm = OS_TimeAssembleFromSubseconds(0, SubSeconds);

return OS_TimeGetMicrosecondsPart(tm);

} /* End of CFE_TIME_Sub2MicroSecs() */

Expand All @@ -549,51 +508,24 @@ uint32 CFE_TIME_Sub2MicroSecs(uint32 SubSeconds)
*/
uint32 CFE_TIME_Micro2SubSecs(uint32 MicroSeconds)
{
OS_time_t tm;
uint32 SubSeconds;

/*
** Conversion amount must be less than one second
** (preserves existing behavior where output saturates at max value)
*/
if (MicroSeconds > 999999)
{
SubSeconds = 0xFFFFFFFF;
}
else
{
/*
** Convert micro-seconds count to sub-seconds (1/2^32) count
**
** Conversion factor is ( ( 10 ** -6 ) / ( 2 ** -20 ).
**
** Logic is as follows:
** x * ( ( 10 ** -6 ) / ( 2 ** -32 ) )
** = x * ( ( 2 ** 32 ) / ( 10 ** 6 ) )
** = x * ( ( ( 2 ** 26 ) ( 2 ** 6) ) / ( ( 5 ** 6 ) ( 2 ** 6 ) ) )
** = x * ( ( 2 ** 26 ) / ( 5 ** 6 ) )
** = x * ( ( ( 2 ** 11) ( 2 ** 3) (2 ** 12) ) / ( 5( 5 ** 5 ) ) )
** = x * ( ( ( ( ( 2 ** 11 ) / 5 ) * ( 2 ** 3 ) ) / ( 5 ** 5 ) ) * (2 ** 12) )
**
** C code equivalent:
** = ( ( ( ( ( x << 11 ) / 5 ) << 3 ) / 3125 ) << 12 )
**
** Conversion factor was reduced and factored accordingly
** to minimize precision loss and register overflow.
*/
SubSeconds = ( ( ( ( MicroSeconds << 11 ) / 5 ) << 3 ) / 3125 ) << 12;

/* To get the SubSeconds to "bump up" against 0xFFFFF000 when
* MicroSeconds = 9999999, we add in another anomaly to the
* conversion at the half-way point (500000 us). This will bump
* all of the subseconds up by 0x1000, so 999999 us == 0xFFFFF00,
* 999998 == 0xFFFFE000, etc. This extra anomaly is accounted for
* in the Sub2MicroSecs conversion as well.
*/

if (SubSeconds > 0x80001000)
{
SubSeconds += 0x1000;
}

/*
** Convert micro-seconds count to sub-seconds (1/2^32) count using OSAL
*/
tm = OS_TimeAssembleFromNanoseconds(0, MicroSeconds * 1000);
SubSeconds = OS_TimeGetSubsecondsPart(tm);
}

return(SubSeconds);
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4 changes: 2 additions & 2 deletions fsw/cfe-core/src/time/cfe_time_utils.c
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Original file line number Diff line number Diff line change
Expand Up @@ -91,8 +91,8 @@ CFE_TIME_SysTime_t CFE_TIME_LatchClock(void)
/*
** Convert time to cFE format (seconds : 1/2^32 subseconds)...
*/
LatchTime.Seconds = LocalTime.seconds;
LatchTime.Subseconds = CFE_TIME_Micro2SubSecs(LocalTime.microsecs);
LatchTime.Seconds = OS_TimeGetTotalSeconds(LocalTime);
LatchTime.Subseconds = OS_TimeGetSubsecondsPart(LocalTime);

return(LatchTime);

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53 changes: 9 additions & 44 deletions fsw/cfe-core/unit-test/time_UT.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1056,38 +1056,28 @@ void Test_ConvertTime(void)
"CFE_TIME_MET2SCTime",
testDesc);

/* NOTE: Microseconds <-> Subseconds conversion routines are implemented
* as part of OS_time_t in OSAL, and are coverage tested there. CFE time
* conversions are now just wrappers of these OSAL routines.
* This should only sanity-check basic values to get coverage of the CFE
* wrappers. Testing of value corner cases / rounding should be limited to
* OSAL coverage test. */

/* Test subseconds to microseconds conversion; zero subsecond value */
UT_InitData();
UT_Report(__FILE__, __LINE__,
CFE_TIME_Sub2MicroSecs(0) == 0,
"CFE_TIME_Sub2MicroSecs",
"Convert 0 subsecond value");

/* Test subseconds to microseconds conversion; positive microsecond
* adjust
*/
UT_InitData();
UT_Report(__FILE__, __LINE__,
CFE_TIME_Sub2MicroSecs(0xffff) == 16,
"CFE_TIME_Sub2MicroSecs",
"+1 microsecond adjustment");

/* Test subseconds to microseconds conversion; no microsecond adjust */
/* Test subseconds to microseconds conversion; half second */
UT_InitData();
UT_Report(__FILE__, __LINE__,
CFE_TIME_Sub2MicroSecs(0x80000000) == 500000,
"CFE_TIME_Sub2MicroSecs",
"No microsecond adjustment");

/* Test subseconds to microseconds conversion; negative microsecond
* adjust
*/
UT_InitData();
UT_Report(__FILE__, __LINE__,
CFE_TIME_Sub2MicroSecs(0x80002000) == 500001,
"CFE_TIME_Sub2MicroSecs",
"-1 microsecond adjustment");

/* Test subseconds to microseconds conversion; subseconds exceeds
* microseconds limit
*/
Expand All @@ -1104,31 +1094,6 @@ void Test_ConvertTime(void)
"CFE_TIME_Micro2SubSecs",
"Convert 0 microseconds to 0 subseconds");

/* Test microseconds to subseconds conversion; no subsecond adjust */
UT_InitData();
UT_Report(__FILE__, __LINE__,
CFE_TIME_Micro2SubSecs(0xffff) == 281468928,
"CFE_TIME_Micro2SubSecs",
"Microseconds below maximum value (no subsecond adjustment)");

/* Test microseconds to subseconds conversion; microseconds below
* maximum limit
*/
UT_InitData();
UT_Report(__FILE__, __LINE__,
CFE_TIME_Micro2SubSecs(999998) == 0xffffe000,
"CFE_TIME_Micro2SubSecs",
"Microseconds below maximum value (subsecond adjustment)");

/* Test microseconds to subseconds conversion; microseconds equals
* maximum limit
*/
UT_InitData();
UT_Report(__FILE__, __LINE__,
CFE_TIME_Micro2SubSecs(999999) == 0xfffff000,
"CFE_TIME_Micro2SubSecs",
"Microseconds equals maximum value (subsecond adjustment)");

/* Test microseconds to subseconds conversion; microseconds exceeds
* maximum limit
*/
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3 changes: 1 addition & 2 deletions fsw/cfe-core/unit-test/ut_support.c
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Original file line number Diff line number Diff line change
Expand Up @@ -373,8 +373,7 @@ void UT_SetBSP_Time(uint32 seconds, uint32 microsecs)
{
OS_time_t BSP_Time;

BSP_Time.seconds = seconds;
BSP_Time.microsecs = microsecs;
BSP_Time = OS_TimeAssembleFromNanoseconds(seconds, microsecs * 1000);

UT_SetDataBuffer(UT_KEY(CFE_PSP_GetTime), &BSP_Time, sizeof(BSP_Time), true);
}
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