diff options
Diffstat (limited to 'hw/mc146818rtc.c')
| -rw-r--r-- | hw/mc146818rtc.c | 40 |
1 files changed, 26 insertions, 14 deletions
diff --git a/hw/mc146818rtc.c b/hw/mc146818rtc.c index d63554f89..332a77d4d 100644 --- a/hw/mc146818rtc.c +++ b/hw/mc146818rtc.c @@ -399,6 +399,10 @@ static void cmos_ioport_write(void *opaque, uint32_t addr, uint32_t data) s->cmos_data[s->cmos_index] = data; check_update_timer(s); break; + case RTC_IBM_PS2_CENTURY_BYTE: + s->cmos_index = RTC_CENTURY; + /* fall through */ + case RTC_CENTURY: case RTC_SECONDS: case RTC_MINUTES: case RTC_HOURS: @@ -515,7 +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) @@ -548,10 +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) @@ -598,6 +603,10 @@ static uint32_t cmos_ioport_read(void *opaque, uint32_t addr) return 0xff; } else { switch(s->cmos_index) { + case RTC_IBM_PS2_CENTURY_BYTE: + s->cmos_index = RTC_CENTURY; + /* fall through */ + case RTC_CENTURY: case RTC_SECONDS: case RTC_MINUTES: case RTC_HOURS: @@ -661,15 +670,10 @@ void rtc_set_memory(ISADevice *dev, int addr, int val) s->cmos_data[addr] = val; } -/* PC cmos mappings */ -#define REG_IBM_CENTURY_BYTE 0x32 -#define REG_IBM_PS2_CENTURY_BYTE 0x37 - 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); @@ -679,10 +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, REG_IBM_CENTURY_BYTE, val); - rtc_set_memory(dev, REG_IBM_PS2_CENTURY_BYTE, val); } static int rtc_post_load(void *opaque, int version_id) @@ -807,6 +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 |