From dc3f9062ca29a36951669751e49ff4f69d108f98 Mon Sep 17 00:00:00 2001
From: "Andrey A. Chernov" <ache@FreeBSD.org>
Date: Mon, 8 Jan 1996 18:50:14 +0000
Subject: [PATCH] Replace ugly year/month calculations in resettodr to more
 clean variants, idea taken from NetBSD clock.c. At least year calculation was
 wrong, pointed by Bruce. Use different strategy to store year for BIOS
 without RTC_CENTURY

---
 sys/amd64/amd64/tsc.c | 26 ++++++++++++--------------
 sys/amd64/isa/clock.c | 26 ++++++++++++--------------
 sys/i386/i386/tsc.c   | 26 ++++++++++++--------------
 sys/i386/isa/clock.c  | 26 ++++++++++++--------------
 sys/isa/atrtc.c       | 26 ++++++++++++--------------
 5 files changed, 60 insertions(+), 70 deletions(-)

diff --git a/sys/amd64/amd64/tsc.c b/sys/amd64/amd64/tsc.c
index 6dc58968f6a..487e7bc3351 100644
--- a/sys/amd64/amd64/tsc.c
+++ b/sys/amd64/amd64/tsc.c
@@ -34,7 +34,7 @@
  * SUCH DAMAGE.
  *
  *	from: @(#)clock.c	7.2 (Berkeley) 5/12/91
- *	$Id: clock.c,v 1.43 1995/12/24 08:10:52 davidg Exp $
+ *	$Id: clock.c,v 1.44 1996/01/04 21:11:33 wollman Exp $
  */
 
 /*
@@ -529,27 +529,25 @@ resettodr()
 
 	/* We have now the days	since 01-01-1970 in tm */
 	writertc(RTC_WDAY, (tm+4)%7);			/* Write back Weekday */
-	for (y=1970;; y++)
-		if ((tm	- DAYSPERYEAR -	LEAPYEAR(y)) > tm)
-			break;
-		else
-			tm -= DAYSPERYEAR + LEAPYEAR(y);
+	for (y = 1970, m = DAYSPERYEAR + LEAPYEAR(y);
+	     tm >= m;
+	     y++,      m = DAYSPERYEAR + LEAPYEAR(y))
+	     tm -= m;
 
 	/* Now we have the years in y and the day-of-the-year in tm */
-	writertc(RTC_YEAR, int2bcd(y%100));		/* Write back Year    */
 #ifdef USE_RTC_CENTURY
+	writertc(RTC_YEAR, int2bcd(y%100));		/* Write back Year    */
 	writertc(RTC_CENTURY, int2bcd(y/100));		/* ... and Century    */
+#else
+	writertc(RTC_YEAR, int2bcd(y - 1900));          /* Write back Year    */
 #endif
 	if (LEAPYEAR(y)	&& (tm >= 31+29))
 		tm--;					/* Subtract Feb-29 */
-	for (m=1;; m++)
-		if (tm - daysinmonth[m-1] > tm)
-			break;
-		else
-			tm -= daysinmonth[m-1];
+	for (m = 0; tm >= daysinmonth[m]; m++)
+		tm -= daysinmonth[m];
 
-	writertc(RTC_MONTH, int2bcd(m));		/* Write back Month   */
-	writertc(RTC_DAY, int2bcd(tm+1));		/* Write back Day     */
+	writertc(RTC_MONTH, int2bcd(m + 1));            /* Write back Month   */
+	writertc(RTC_DAY, int2bcd(tm + 1));             /* Write back Month Day */
 
 	/* Reenable RTC updates and interrupts. */
 	writertc(RTC_STATUSB, RTCSB_24HR | RTCSB_PINTR);
diff --git a/sys/amd64/isa/clock.c b/sys/amd64/isa/clock.c
index 6dc58968f6a..487e7bc3351 100644
--- a/sys/amd64/isa/clock.c
+++ b/sys/amd64/isa/clock.c
@@ -34,7 +34,7 @@
  * SUCH DAMAGE.
  *
  *	from: @(#)clock.c	7.2 (Berkeley) 5/12/91
- *	$Id: clock.c,v 1.43 1995/12/24 08:10:52 davidg Exp $
+ *	$Id: clock.c,v 1.44 1996/01/04 21:11:33 wollman Exp $
  */
 
 /*
@@ -529,27 +529,25 @@ resettodr()
 
 	/* We have now the days	since 01-01-1970 in tm */
 	writertc(RTC_WDAY, (tm+4)%7);			/* Write back Weekday */
-	for (y=1970;; y++)
-		if ((tm	- DAYSPERYEAR -	LEAPYEAR(y)) > tm)
-			break;
-		else
-			tm -= DAYSPERYEAR + LEAPYEAR(y);
+	for (y = 1970, m = DAYSPERYEAR + LEAPYEAR(y);
+	     tm >= m;
+	     y++,      m = DAYSPERYEAR + LEAPYEAR(y))
+	     tm -= m;
 
 	/* Now we have the years in y and the day-of-the-year in tm */
-	writertc(RTC_YEAR, int2bcd(y%100));		/* Write back Year    */
 #ifdef USE_RTC_CENTURY
+	writertc(RTC_YEAR, int2bcd(y%100));		/* Write back Year    */
 	writertc(RTC_CENTURY, int2bcd(y/100));		/* ... and Century    */
+#else
+	writertc(RTC_YEAR, int2bcd(y - 1900));          /* Write back Year    */
 #endif
 	if (LEAPYEAR(y)	&& (tm >= 31+29))
 		tm--;					/* Subtract Feb-29 */
-	for (m=1;; m++)
-		if (tm - daysinmonth[m-1] > tm)
-			break;
-		else
-			tm -= daysinmonth[m-1];
+	for (m = 0; tm >= daysinmonth[m]; m++)
+		tm -= daysinmonth[m];
 
-	writertc(RTC_MONTH, int2bcd(m));		/* Write back Month   */
-	writertc(RTC_DAY, int2bcd(tm+1));		/* Write back Day     */
+	writertc(RTC_MONTH, int2bcd(m + 1));            /* Write back Month   */
+	writertc(RTC_DAY, int2bcd(tm + 1));             /* Write back Month Day */
 
 	/* Reenable RTC updates and interrupts. */
 	writertc(RTC_STATUSB, RTCSB_24HR | RTCSB_PINTR);
diff --git a/sys/i386/i386/tsc.c b/sys/i386/i386/tsc.c
index 6dc58968f6a..487e7bc3351 100644
--- a/sys/i386/i386/tsc.c
+++ b/sys/i386/i386/tsc.c
@@ -34,7 +34,7 @@
  * SUCH DAMAGE.
  *
  *	from: @(#)clock.c	7.2 (Berkeley) 5/12/91
- *	$Id: clock.c,v 1.43 1995/12/24 08:10:52 davidg Exp $
+ *	$Id: clock.c,v 1.44 1996/01/04 21:11:33 wollman Exp $
  */
 
 /*
@@ -529,27 +529,25 @@ resettodr()
 
 	/* We have now the days	since 01-01-1970 in tm */
 	writertc(RTC_WDAY, (tm+4)%7);			/* Write back Weekday */
-	for (y=1970;; y++)
-		if ((tm	- DAYSPERYEAR -	LEAPYEAR(y)) > tm)
-			break;
-		else
-			tm -= DAYSPERYEAR + LEAPYEAR(y);
+	for (y = 1970, m = DAYSPERYEAR + LEAPYEAR(y);
+	     tm >= m;
+	     y++,      m = DAYSPERYEAR + LEAPYEAR(y))
+	     tm -= m;
 
 	/* Now we have the years in y and the day-of-the-year in tm */
-	writertc(RTC_YEAR, int2bcd(y%100));		/* Write back Year    */
 #ifdef USE_RTC_CENTURY
+	writertc(RTC_YEAR, int2bcd(y%100));		/* Write back Year    */
 	writertc(RTC_CENTURY, int2bcd(y/100));		/* ... and Century    */
+#else
+	writertc(RTC_YEAR, int2bcd(y - 1900));          /* Write back Year    */
 #endif
 	if (LEAPYEAR(y)	&& (tm >= 31+29))
 		tm--;					/* Subtract Feb-29 */
-	for (m=1;; m++)
-		if (tm - daysinmonth[m-1] > tm)
-			break;
-		else
-			tm -= daysinmonth[m-1];
+	for (m = 0; tm >= daysinmonth[m]; m++)
+		tm -= daysinmonth[m];
 
-	writertc(RTC_MONTH, int2bcd(m));		/* Write back Month   */
-	writertc(RTC_DAY, int2bcd(tm+1));		/* Write back Day     */
+	writertc(RTC_MONTH, int2bcd(m + 1));            /* Write back Month   */
+	writertc(RTC_DAY, int2bcd(tm + 1));             /* Write back Month Day */
 
 	/* Reenable RTC updates and interrupts. */
 	writertc(RTC_STATUSB, RTCSB_24HR | RTCSB_PINTR);
diff --git a/sys/i386/isa/clock.c b/sys/i386/isa/clock.c
index 6dc58968f6a..487e7bc3351 100644
--- a/sys/i386/isa/clock.c
+++ b/sys/i386/isa/clock.c
@@ -34,7 +34,7 @@
  * SUCH DAMAGE.
  *
  *	from: @(#)clock.c	7.2 (Berkeley) 5/12/91
- *	$Id: clock.c,v 1.43 1995/12/24 08:10:52 davidg Exp $
+ *	$Id: clock.c,v 1.44 1996/01/04 21:11:33 wollman Exp $
  */
 
 /*
@@ -529,27 +529,25 @@ resettodr()
 
 	/* We have now the days	since 01-01-1970 in tm */
 	writertc(RTC_WDAY, (tm+4)%7);			/* Write back Weekday */
-	for (y=1970;; y++)
-		if ((tm	- DAYSPERYEAR -	LEAPYEAR(y)) > tm)
-			break;
-		else
-			tm -= DAYSPERYEAR + LEAPYEAR(y);
+	for (y = 1970, m = DAYSPERYEAR + LEAPYEAR(y);
+	     tm >= m;
+	     y++,      m = DAYSPERYEAR + LEAPYEAR(y))
+	     tm -= m;
 
 	/* Now we have the years in y and the day-of-the-year in tm */
-	writertc(RTC_YEAR, int2bcd(y%100));		/* Write back Year    */
 #ifdef USE_RTC_CENTURY
+	writertc(RTC_YEAR, int2bcd(y%100));		/* Write back Year    */
 	writertc(RTC_CENTURY, int2bcd(y/100));		/* ... and Century    */
+#else
+	writertc(RTC_YEAR, int2bcd(y - 1900));          /* Write back Year    */
 #endif
 	if (LEAPYEAR(y)	&& (tm >= 31+29))
 		tm--;					/* Subtract Feb-29 */
-	for (m=1;; m++)
-		if (tm - daysinmonth[m-1] > tm)
-			break;
-		else
-			tm -= daysinmonth[m-1];
+	for (m = 0; tm >= daysinmonth[m]; m++)
+		tm -= daysinmonth[m];
 
-	writertc(RTC_MONTH, int2bcd(m));		/* Write back Month   */
-	writertc(RTC_DAY, int2bcd(tm+1));		/* Write back Day     */
+	writertc(RTC_MONTH, int2bcd(m + 1));            /* Write back Month   */
+	writertc(RTC_DAY, int2bcd(tm + 1));             /* Write back Month Day */
 
 	/* Reenable RTC updates and interrupts. */
 	writertc(RTC_STATUSB, RTCSB_24HR | RTCSB_PINTR);
diff --git a/sys/isa/atrtc.c b/sys/isa/atrtc.c
index 6dc58968f6a..487e7bc3351 100644
--- a/sys/isa/atrtc.c
+++ b/sys/isa/atrtc.c
@@ -34,7 +34,7 @@
  * SUCH DAMAGE.
  *
  *	from: @(#)clock.c	7.2 (Berkeley) 5/12/91
- *	$Id: clock.c,v 1.43 1995/12/24 08:10:52 davidg Exp $
+ *	$Id: clock.c,v 1.44 1996/01/04 21:11:33 wollman Exp $
  */
 
 /*
@@ -529,27 +529,25 @@ resettodr()
 
 	/* We have now the days	since 01-01-1970 in tm */
 	writertc(RTC_WDAY, (tm+4)%7);			/* Write back Weekday */
-	for (y=1970;; y++)
-		if ((tm	- DAYSPERYEAR -	LEAPYEAR(y)) > tm)
-			break;
-		else
-			tm -= DAYSPERYEAR + LEAPYEAR(y);
+	for (y = 1970, m = DAYSPERYEAR + LEAPYEAR(y);
+	     tm >= m;
+	     y++,      m = DAYSPERYEAR + LEAPYEAR(y))
+	     tm -= m;
 
 	/* Now we have the years in y and the day-of-the-year in tm */
-	writertc(RTC_YEAR, int2bcd(y%100));		/* Write back Year    */
 #ifdef USE_RTC_CENTURY
+	writertc(RTC_YEAR, int2bcd(y%100));		/* Write back Year    */
 	writertc(RTC_CENTURY, int2bcd(y/100));		/* ... and Century    */
+#else
+	writertc(RTC_YEAR, int2bcd(y - 1900));          /* Write back Year    */
 #endif
 	if (LEAPYEAR(y)	&& (tm >= 31+29))
 		tm--;					/* Subtract Feb-29 */
-	for (m=1;; m++)
-		if (tm - daysinmonth[m-1] > tm)
-			break;
-		else
-			tm -= daysinmonth[m-1];
+	for (m = 0; tm >= daysinmonth[m]; m++)
+		tm -= daysinmonth[m];
 
-	writertc(RTC_MONTH, int2bcd(m));		/* Write back Month   */
-	writertc(RTC_DAY, int2bcd(tm+1));		/* Write back Day     */
+	writertc(RTC_MONTH, int2bcd(m + 1));            /* Write back Month   */
+	writertc(RTC_DAY, int2bcd(tm + 1));             /* Write back Month Day */
 
 	/* Reenable RTC updates and interrupts. */
 	writertc(RTC_STATUSB, RTCSB_24HR | RTCSB_PINTR);