commit 1bb34a412750291e4e5e9f1d0fe7ae1b7e976098
author john stultz <johnstul@us.ibm.com> Sun Oct 30 15:01:42 2005 -0800
committer Linus Torvalds <torvalds@g5.osdl.org> Sun Oct 30 17:37:18 2005 -0800
tree 00d481a2ff4302f444fbf7c31e5e661f79dc85a9
parent 9c0cbd54ce0397017a823484f9a8054ab369b8a2

[PATCH] NTP shift_right cleanup

Create a macro shift_right() that avoids the numerous ugly conditionals in the
NTP code that look like:

        if(a < 0)
                b = -(-a >> shift);
        else
                b = a >> shift;

Replacing it with:

        b = shift_right(a, shift);

This should have zero effect on the logic, however it should probably have
a bit of testing just to be sure.

Also replace open-coded min/max with the macros.

Signed-off-by : John Stultz <johnstul@us.ibm.com>

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

kernel/time.c

diff --git a/kernel/time.c b/kernel/time.c
index a3c2100..245d595 100644
--- a/kernel/time.c
+++ b/kernel/time.c
@@ -338,30 +338,20 @@
 		        if (mtemp >= MINSEC) {
 			    ltemp = (time_offset / mtemp) << (SHIFT_USEC -
 							      SHIFT_UPDATE);
-			    if (ltemp < 0)
-			        time_freq -= -ltemp >> SHIFT_KH;
-			    else
-			        time_freq += ltemp >> SHIFT_KH;
+			    time_freq += shift_right(ltemp, SHIFT_KH);
 			} else /* calibration interval too short (p. 12) */
 				result = TIME_ERROR;
 		    } else {	/* PLL mode */
 		        if (mtemp < MAXSEC) {
 			    ltemp *= mtemp;
-			    if (ltemp < 0)
-			        time_freq -= -ltemp >> (time_constant +
-							time_constant +
-							SHIFT_KF - SHIFT_USEC);
-			    else
-			        time_freq += ltemp >> (time_constant +
+			    time_freq += shift_right(ltemp,(time_constant +
 						       time_constant +
-						       SHIFT_KF - SHIFT_USEC);
+						       SHIFT_KF - SHIFT_USEC));
 			} else /* calibration interval too long (p. 12) */
 				result = TIME_ERROR;
 		    }
-		    if (time_freq > time_tolerance)
-		        time_freq = time_tolerance;
-		    else if (time_freq < -time_tolerance)
-		        time_freq = -time_tolerance;
+		    time_freq = min(time_freq, time_tolerance);
+		    time_freq = max(time_freq, -time_tolerance);
 		} /* STA_PLL || STA_PPSTIME */
 	    } /* txc->modes & ADJ_OFFSET */
 	    if (txc->modes & ADJ_TICK) {
@@ -384,10 +374,7 @@
 	if ((txc->modes & ADJ_OFFSET_SINGLESHOT) == ADJ_OFFSET_SINGLESHOT)
 	    txc->offset	   = save_adjust;
 	else {
-	    if (time_offset < 0)
-		txc->offset = -(-time_offset >> SHIFT_UPDATE);
-	    else
-		txc->offset = time_offset >> SHIFT_UPDATE;
+	    txc->offset = shift_right(time_offset, SHIFT_UPDATE);
 	}
 	txc->freq	   = time_freq + pps_freq;
 	txc->maxerror	   = time_maxerror;