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Optimize reading the CMOS real time clock.

This commit is contained in:
Jonas 'Sortie' Termansen 2014-05-09 18:32:15 +02:00
parent ae73391a10
commit c1af231897
1 changed files with 56 additions and 11 deletions
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67
kernel/x86-family/cmos.cpp
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@ -1,6 +1,6 @@
/*******************************************************************************
Copyright(C) Jonas 'Sortie' Termansen 2013.
Copyright(C) Jonas 'Sortie' Termansen 2013, 2014.
This file is part of Sortix.
@ -58,18 +58,63 @@ uint8_t DecodeBCD(uint8_t bcd)
return bcd / 16 * 10 + bcd % 16;
}
struct rtc_values
{
uint8_t second;
uint8_t minute;
uint8_t hour;
uint8_t day;
uint8_t month;
uint8_t year;
uint8_t century;
uint8_t reg_b;
};
bool are_rtc_values_equal(struct rtc_values a, struct rtc_values b)
{
return a.second == b.second &&
a.minute == b.minute &&
a.hour == b.hour &&
a.day == b.day &&
a.month == b.month &&
a.year == b.year &&
a.century == b.century &&
a.reg_b == b.reg_b;
}
struct rtc_values ReadRTCValues()
{
while ( IsRTCUpdateInProgress() );
struct rtc_values result;
result.second = ReadRTC(0x00);
result.minute = ReadRTC(0x02);
result.hour = ReadRTC(0x04);
result.day = ReadRTC(0x07);
result.month = ReadRTC(0x08);
result.year = ReadRTC(0x09);
result.century = ReadRTC(0x32);
result.reg_b = ReadRTC(0x0B);
return result;
}
void Init()
{
while ( !IsRTCUpdateInProgress() );
while ( IsRTCUpdateInProgress() );
uint8_t second = ReadRTC(0x00);
uint8_t minute = ReadRTC(0x02);
uint8_t hour = ReadRTC(0x04);
uint8_t day = ReadRTC(0x07);
uint8_t month = ReadRTC(0x08);
uint8_t year = ReadRTC(0x09);
uint8_t century = ReadRTC(0x32);
uint8_t reg_b = ReadRTC(0x0B);
struct rtc_values values_first = ReadRTCValues();
struct rtc_values values_second = ReadRTCValues();
while ( !are_rtc_values_equal(values_first, values_second) )
{
values_first = values_second;
values_second = ReadRTCValues();
}
uint8_t second = values_first.second;
uint8_t minute = values_first.minute;
uint8_t hour = values_first.hour;
uint8_t day = values_first.day;
uint8_t month = values_first.month;
uint8_t year = values_first.year;
uint8_t century = values_first.century;
uint8_t reg_b = values_first.reg_b;
bool hour12 = !(reg_b & 0x02);
bool is_pm = hour12 && hour & 0x80;