[Xen-devel] [PATCH] x86/time: Remove redundant RTC REG_B read

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

RTC_ALWAYS_BCD is always defined by default, meaning that we will
unconditionally enter the if statement.  Reordering the condition allows
short-circult evaluation to remove a redundant CMOS read.

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CC: Keir Fraser <keir@xxxxxxx>
CC: Jan Beulich <JBeulich@xxxxxxxx>
---
 xen/arch/x86/time.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/xen/arch/x86/time.c b/xen/arch/x86/time.c
index 6e31e1f..82492c1 100644
--- a/xen/arch/x86/time.c
+++ b/xen/arch/x86/time.c
@@ -661,7 +661,7 @@ static unsigned long __get_cmos_time(void)
     mon  = CMOS_READ(RTC_MONTH);
     year = CMOS_READ(RTC_YEAR);
     
-    if ( !(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY) || RTC_ALWAYS_BCD )
+    if ( RTC_ALWAYS_BCD || !(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY) )
     {
         BCD_TO_BIN(sec);
         BCD_TO_BIN(min);
-- 
1.7.10.4


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