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| author | Joel Sherrill <joel.sherrill@OARcorp.com> | 2010-03-10 17:16:11 +0000 |
|---|---|---|
| committer | Joel Sherrill <joel.sherrill@OARcorp.com> | 2010-03-10 17:16:11 +0000 |
| commit | f1c5a5228f91993c90504652dbc10e39cbd0c967 (patch) | |
| tree | 7f3bcaff117b59d24e0ddde53c36cbf5df4abdcd | |
| parent | 2010-03-10 Joel Sherrill <joel.sherrill@oarcorp.com> (diff) | |
| download | rtems-f1c5a5228f91993c90504652dbc10e39cbd0c967.tar.bz2 | |
2010-03-10 Gedare Bloom <gedare@gwu.edu>
PR 1495/bsp
* clock/ckinit.c: Calling rtems_clock_get_uptime() in a tight loop
sometimes showed time moving backwards.
| -rw-r--r-- | c/src/lib/libbsp/i386/pc386/ChangeLog | 6 | ||||
| -rw-r--r-- | c/src/lib/libbsp/i386/pc386/clock/ckinit.c | 16 |
2 files changed, 22 insertions, 0 deletions
diff --git a/c/src/lib/libbsp/i386/pc386/ChangeLog b/c/src/lib/libbsp/i386/pc386/ChangeLog index c45515ef08..a846549bd8 100644 --- a/c/src/lib/libbsp/i386/pc386/ChangeLog +++ b/c/src/lib/libbsp/i386/pc386/ChangeLog @@ -1,3 +1,9 @@ +2010-03-10 Gedare Bloom <gedare@gwu.edu> + + PR 1495/bsp + * clock/ckinit.c: Calling rtems_clock_get_uptime() in a tight loop + sometimes showed time moving backwards. + 2009-09-15 Till Straumann <strauman@slac.stanford.edu> PR 1344/bsps: diff --git a/c/src/lib/libbsp/i386/pc386/clock/ckinit.c b/c/src/lib/libbsp/i386/pc386/clock/ckinit.c index ff5b9c46c1..22519a98ee 100644 --- a/c/src/lib/libbsp/i386/pc386/clock/ckinit.c +++ b/c/src/lib/libbsp/i386/pc386/clock/ckinit.c @@ -47,6 +47,11 @@ uint64_t pc586_tsc_at_tick; /* this driver may need to count ISRs per tick */ #define CLOCK_DRIVER_ISRS_PER_TICK pc386_isrs_per_tick +/* if so, the driver may use the count in Clock_driver_support_at_tick */ +#ifdef CLOCK_DRIVER_ISRS_PER_TICK +extern volatile uint32_t Clock_driver_isrs; +#endif + #define READ_8254( _lsb, _msb ) \ do { outport_byte(TIMER_MODE, TIMER_SEL0|TIMER_LATCH); \ inport_byte(TIMER_CNTR0, _lsb); \ @@ -66,7 +71,18 @@ uint32_t (*Clock_driver_nanoseconds_since_last_tick)(void) = NULL; */ void Clock_driver_support_at_tick_tsc(void) { +#ifdef CLOCK_DRIVER_ISRS_PER_TICK + /* + * The driver is multiple ISRs per clock tick. + */ + if (!Clock_driver_isrs) + pc586_tsc_at_tick = rdtsc(); +#else + /* + * The driver is one ISR per clock tick. + */ pc586_tsc_at_tick = rdtsc(); +#endif } void Clock_driver_support_at_tick_empty(void) |