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[Qemu-devel] [PATCH 04/14] timer: ds1338 clarify HOUR handling
From: |
Michael Davidsaver |
Subject: |
[Qemu-devel] [PATCH 04/14] timer: ds1338 clarify HOUR handling |
Date: |
Sat, 24 Mar 2018 12:24:45 -0700 |
Simplify and comment the translation between
registers and struct tm.
Signed-off-by: Michael Davidsaver <address@hidden>
---
hw/timer/ds1338.c | 35 +++++++++++++++++------------------
1 file changed, 17 insertions(+), 18 deletions(-)
diff --git a/hw/timer/ds1338.c b/hw/timer/ds1338.c
index 72a4692d60..9bcda26e51 100644
--- a/hw/timer/ds1338.c
+++ b/hw/timer/ds1338.c
@@ -88,23 +88,23 @@ static void capture_current_time(DS1338State *s)
* which will be actually read by the data transfer operation.
*/
struct tm now;
+ bool mode12 = ARRAY_FIELD_EX32(s->nvram, HOUR, SET12);
qemu_get_timedate(&now, s->offset);
+
s->nvram[R_SEC] = to_bcd(now.tm_sec);
s->nvram[R_MIN] = to_bcd(now.tm_min);
- if (ARRAY_FIELD_EX32(s->nvram, HOUR, SET12)) {
- int tmp = now.tm_hour;
- if (tmp % 12 == 0) {
- tmp += 12;
- }
- s->nvram[R_HOUR] = 0;
+ s->nvram[R_HOUR] = 0;
+ if (mode12) {
+ /* map 0-23 to 1-12 am/pm */
ARRAY_FIELD_DP32(s->nvram, HOUR, SET12, 1);
- if (tmp <= 12) {
- ARRAY_FIELD_DP32(s->nvram, HOUR, AMPM, 0);
- ARRAY_FIELD_DP32(s->nvram, HOUR, HOUR12, to_bcd(tmp));
- } else {
- ARRAY_FIELD_DP32(s->nvram, HOUR, AMPM, 1);
- ARRAY_FIELD_DP32(s->nvram, HOUR, HOUR12, to_bcd(tmp - 12));
+ ARRAY_FIELD_DP32(s->nvram, HOUR, AMPM, now.tm_hour >= 12u);
+ now.tm_hour %= 12u; /* wrap 0-23 to 0-11 */
+ if (now.tm_hour == 0u) {
+ /* midnight/noon stored as 12 */
+ now.tm_hour = 12u;
}
+ ARRAY_FIELD_DP32(s->nvram, HOUR, HOUR12, to_bcd(now.tm_hour));
+
} else {
ARRAY_FIELD_DP32(s->nvram, HOUR, HOUR24, to_bcd(now.tm_hour));
}
@@ -182,14 +182,13 @@ static int ds1338_send(I2CSlave *i2c, uint8_t data)
break;
case R_HOUR:
if (FIELD_EX32(data, HOUR, SET12)) {
- int tmp = from_bcd(FIELD_EX32(data, HOUR, HOUR12));
+ /* 12 hour (1-12) */
+ /* read and wrap 1-12 -> 0-11 */
+ now.tm_hour = from_bcd(FIELD_EX32(data, HOUR, HOUR12)) % 12u;
if (FIELD_EX32(data, HOUR, AMPM)) {
- tmp += 12;
+ now.tm_hour += 12;
}
- if (tmp % 12 == 0) {
- tmp -= 12;
- }
- now.tm_hour = tmp;
+
} else {
now.tm_hour = from_bcd(FIELD_EX32(data, HOUR, HOUR24));
}
--
2.11.0
- [Qemu-devel] [PATCH 00/14] Generalize Dallas/Maxim I2C RTC devices v2, Michael Davidsaver, 2018/03/24
- [Qemu-devel] [PATCH 05/14] timer: ds1338 change write handling, Michael Davidsaver, 2018/03/24
- [Qemu-devel] [PATCH 14/14] tests: drop ds1338-test, Michael Davidsaver, 2018/03/24
- [Qemu-devel] [PATCH 08/14] tests: ds-rtc test wday offset, Michael Davidsaver, 2018/03/24
- [Qemu-devel] [PATCH 12/14] timer: ds-rtc handle CENTURY bit, Michael Davidsaver, 2018/03/24
- [Qemu-devel] [PATCH 02/14] timer: ds1338 use registerfields.h, Michael Davidsaver, 2018/03/24
- [Qemu-devel] [PATCH 09/14] timer: rename ds1338 -> dsrtc, Michael Davidsaver, 2018/03/24
- [Qemu-devel] [PATCH 06/14] tests: ds-rtc test 12 hour mode, Michael Davidsaver, 2018/03/24
- [Qemu-devel] [PATCH 04/14] timer: ds1338 clarify HOUR handling,
Michael Davidsaver <=
- [Qemu-devel] [PATCH 10/14] timer: rename file ds1338.c -> ds-rtc.c, Michael Davidsaver, 2018/03/24
- [Qemu-devel] [PATCH 01/14] tests: more thorough tests of ds1338, Michael Davidsaver, 2018/03/24
- [Qemu-devel] [PATCH 07/14] timer: ds1338 fix wday_offset handling, Michael Davidsaver, 2018/03/24
- [Qemu-devel] [PATCH 13/14] timer: ds-rtc model ds1375, Michael Davidsaver, 2018/03/24
- [Qemu-devel] [PATCH 03/14] timer: ds1338 persist 12-hour mode selection, Michael Davidsaver, 2018/03/24
- [Qemu-devel] [PATCH 11/14] timer: generalize ds1338, Michael Davidsaver, 2018/03/24
- Re: [Qemu-devel] [PATCH 00/14] Generalize Dallas/Maxim I2C RTC devices v2, no-reply, 2018/03/24
- Re: [Qemu-devel] [PATCH 00/14] Generalize Dallas/Maxim I2C RTC devices v2, no-reply, 2018/03/24