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-rw-r--r--hw/mc146818rtc.c27
-rw-r--r--tests/rtc-test.c32
2 files changed, 48 insertions, 11 deletions
diff --git a/hw/mc146818rtc.c b/hw/mc146818rtc.c
index a7d20d5c25..332a77d4dc 100644
--- a/hw/mc146818rtc.c
+++ b/hw/mc146818rtc.c
@@ -519,7 +519,9 @@ static void rtc_get_time(RTCState *s, struct tm *tm)
tm->tm_wday = rtc_from_bcd(s, s->cmos_data[RTC_DAY_OF_WEEK]) - 1;
tm->tm_mday = rtc_from_bcd(s, s->cmos_data[RTC_DAY_OF_MONTH]);
tm->tm_mon = rtc_from_bcd(s, s->cmos_data[RTC_MONTH]) - 1;
- tm->tm_year = rtc_from_bcd(s, s->cmos_data[RTC_YEAR]) + s->base_year - 1900;
+ tm->tm_year =
+ rtc_from_bcd(s, s->cmos_data[RTC_YEAR]) + s->base_year +
+ rtc_from_bcd(s, s->cmos_data[RTC_CENTURY]) * 100 - 1900;
}
static void rtc_set_time(RTCState *s)
@@ -552,10 +554,9 @@ static void rtc_set_cmos(RTCState *s, const struct tm *tm)
s->cmos_data[RTC_DAY_OF_WEEK] = rtc_to_bcd(s, tm->tm_wday + 1);
s->cmos_data[RTC_DAY_OF_MONTH] = rtc_to_bcd(s, tm->tm_mday);
s->cmos_data[RTC_MONTH] = rtc_to_bcd(s, tm->tm_mon + 1);
- year = (tm->tm_year - s->base_year) % 100;
- if (year < 0)
- year += 100;
- s->cmos_data[RTC_YEAR] = rtc_to_bcd(s, year);
+ year = tm->tm_year + 1900 - s->base_year;
+ s->cmos_data[RTC_YEAR] = rtc_to_bcd(s, year % 100);
+ s->cmos_data[RTC_CENTURY] = rtc_to_bcd(s, year / 100);
}
static void rtc_update_time(RTCState *s)
@@ -673,7 +674,6 @@ static void rtc_set_date_from_host(ISADevice *dev)
{
RTCState *s = DO_UPCAST(RTCState, dev, dev);
struct tm tm;
- int val;
qemu_get_timedate(&tm, 0);
@@ -683,9 +683,6 @@ static void rtc_set_date_from_host(ISADevice *dev)
/* set the CMOS date */
rtc_set_cmos(s, &tm);
-
- val = rtc_to_bcd(s, (tm.tm_year / 100) + 19);
- rtc_set_memory(dev, RTC_CENTURY, val);
}
static int rtc_post_load(void *opaque, int version_id)
@@ -810,6 +807,18 @@ static int rtc_initfn(ISADevice *dev)
s->cmos_data[RTC_REG_C] = 0x00;
s->cmos_data[RTC_REG_D] = 0x80;
+ /* This is for historical reasons. The default base year qdev property
+ * was set to 2000 for most machine types before the century byte was
+ * implemented.
+ *
+ * This if statement means that the century byte will be always 0
+ * (at least until 2079...) for base_year = 1980, but will be set
+ * correctly for base_year = 2000.
+ */
+ if (s->base_year == 2000) {
+ s->base_year = 0;
+ }
+
rtc_set_date_from_host(dev);
#ifdef TARGET_I386
diff --git a/tests/rtc-test.c b/tests/rtc-test.c
index 2b9aa63c1f..7fdc94a3de 100644
--- a/tests/rtc-test.c
+++ b/tests/rtc-test.c
@@ -179,12 +179,13 @@ static void check_time(int wiggle)
static int wiggle = 2;
-static void set_year(void)
+static void set_year_20xx(void)
{
/* Set BCD mode */
cmos_write(RTC_REG_B, cmos_read(RTC_REG_B) & ~REG_B_DM);
cmos_write(RTC_REG_A, 0x76);
cmos_write(RTC_YEAR, 0x11);
+ cmos_write(RTC_CENTURY, 0x20);
cmos_write(RTC_MONTH, 0x02);
cmos_write(RTC_DAY_OF_MONTH, 0x02);
cmos_write(RTC_HOURS, 0x02);
@@ -198,6 +199,7 @@ static void set_year(void)
g_assert_cmpint(cmos_read(RTC_DAY_OF_MONTH), ==, 0x02);
g_assert_cmpint(cmos_read(RTC_MONTH), ==, 0x02);
g_assert_cmpint(cmos_read(RTC_YEAR), ==, 0x11);
+ g_assert_cmpint(cmos_read(RTC_CENTURY), ==, 0x20);
/* Set a date in 2080 to ensure there is no year-2038 overflow. */
cmos_write(RTC_REG_A, 0x76);
@@ -210,6 +212,7 @@ static void set_year(void)
g_assert_cmpint(cmos_read(RTC_DAY_OF_MONTH), ==, 0x02);
g_assert_cmpint(cmos_read(RTC_MONTH), ==, 0x02);
g_assert_cmpint(cmos_read(RTC_YEAR), ==, 0x80);
+ g_assert_cmpint(cmos_read(RTC_CENTURY), ==, 0x20);
cmos_write(RTC_REG_A, 0x76);
cmos_write(RTC_YEAR, 0x11);
@@ -221,6 +224,30 @@ static void set_year(void)
g_assert_cmpint(cmos_read(RTC_DAY_OF_MONTH), ==, 0x02);
g_assert_cmpint(cmos_read(RTC_MONTH), ==, 0x02);
g_assert_cmpint(cmos_read(RTC_YEAR), ==, 0x11);
+ g_assert_cmpint(cmos_read(RTC_CENTURY), ==, 0x20);
+}
+
+static void set_year_1980(void)
+{
+ /* Set BCD mode */
+ cmos_write(RTC_REG_B, cmos_read(RTC_REG_B) & ~REG_B_DM);
+ cmos_write(RTC_REG_A, 0x76);
+ cmos_write(RTC_YEAR, 0x80);
+ cmos_write(RTC_CENTURY, 0x19);
+ cmos_write(RTC_MONTH, 0x02);
+ cmos_write(RTC_DAY_OF_MONTH, 0x02);
+ cmos_write(RTC_HOURS, 0x02);
+ cmos_write(RTC_MINUTES, 0x04);
+ cmos_write(RTC_SECONDS, 0x58);
+ cmos_write(RTC_REG_A, 0x26);
+
+ g_assert_cmpint(cmos_read(RTC_HOURS), ==, 0x02);
+ g_assert_cmpint(cmos_read(RTC_MINUTES), ==, 0x04);
+ g_assert_cmpint(cmos_read(RTC_SECONDS), >=, 0x58);
+ g_assert_cmpint(cmos_read(RTC_DAY_OF_MONTH), ==, 0x02);
+ g_assert_cmpint(cmos_read(RTC_MONTH), ==, 0x02);
+ g_assert_cmpint(cmos_read(RTC_YEAR), ==, 0x80);
+ g_assert_cmpint(cmos_read(RTC_CENTURY), ==, 0x19);
}
static void bcd_check_time(void)
@@ -313,7 +340,8 @@ int main(int argc, char **argv)
qtest_add_func("/rtc/bcd/check-time", bcd_check_time);
qtest_add_func("/rtc/dec/check-time", dec_check_time);
qtest_add_func("/rtc/alarm-time", alarm_time);
- qtest_add_func("/rtc/set-year", set_year);
+ qtest_add_func("/rtc/set-year/20xx", set_year_20xx);
+ qtest_add_func("/rtc/set-year/1980", set_year_1980);
qtest_add_func("/rtc/fuzz-registers", fuzz_registers);
ret = g_test_run();