PEL: Add BCD time helpers for PELs

A PEL stores time in BCD, with a byte each for:
* year MSB
* year LSB
* month
* day
* hour
* minutes
* seconds
* hundredths

This commit adds a structure to represent this, and functions to:
* Create a BCD structure from a std::chrono::time_point
* Convert any number to BCD
* Write the BCD structure into a Stream
* Extract a BCD structure from a Stream

Refresher: The BCD value of 32 is 0x32.

Signed-off-by: Matt Spinler <spinler@us.ibm.com>
Change-Id: I09ea4098f3a3981931f595d11fb63aff31d9fb0d

1 files changed, 61 insertions, 0 deletions

diff --git a/extensions/openpower-pels/bcd_time.cpp b/extensions/openpower-pels/bcd_time.cpp
new file mode 100644
index 0000000..bb80f1a
--- /dev/null
+++ b/extensions/openpower-pels/bcd_time.cpp
@@ -0,0 +1,61 @@
+#include "bcd_time.hpp"
+
+namespace openpower
+{
+namespace pels
+{
+
+bool BCDTime::operator==(const BCDTime& right) const
+{
+    return (yearMSB == right.yearMSB) && (yearLSB == right.yearLSB) &&
+           (month == right.month) && (day == right.day) &&
+           (hour == right.hour) && (minutes == right.minutes) &&
+           (seconds == right.seconds) && (hundredths == right.hundredths);
+}
+
+bool BCDTime::operator!=(const BCDTime& right) const
+{
+    return !(*this == right);
+}
+
+BCDTime getBCDTime(std::chrono::time_point<std::chrono::system_clock>& time)
+{
+    BCDTime bcd;
+
+    using namespace std::chrono;
+    time_t t = system_clock::to_time_t(time);
+    tm* localTime = localtime(&t);
+    assert(localTime != nullptr);
+
+    int year = 1900 + localTime->tm_year;
+    bcd.yearMSB = toBCD(year / 100);
+    bcd.yearLSB = toBCD(year % 100);
+    bcd.month = toBCD(localTime->tm_mon + 1);
+    bcd.day = toBCD(localTime->tm_mday);
+    bcd.hour = toBCD(localTime->tm_hour);
+    bcd.minutes = toBCD(localTime->tm_min);
+    bcd.seconds = toBCD(localTime->tm_sec);
+
+    auto ms = duration_cast<milliseconds>(time.time_since_epoch()).count();
+    int hundredths = (ms % 1000) / 10;
+    bcd.hundredths = toBCD(hundredths);
+
+    return bcd;
+}
+
+Stream& operator>>(Stream& s, BCDTime& time)
+{
+    s >> time.yearMSB >> time.yearLSB >> time.month >> time.day >> time.hour;
+    s >> time.minutes >> time.seconds >> time.hundredths;
+    return s;
+}
+
+Stream& operator<<(Stream& s, BCDTime& time)
+{
+    s << time.yearMSB << time.yearLSB << time.month << time.day << time.hour;
+    s << time.minutes << time.seconds << time.hundredths;
+    return s;
+}
+
+} // namespace pels
+} // namespace openpower