forked from Minki/linux
[PATCH] x86_64: Make use of the *PER* constants in time.c
This patch makes use of the newly added conversion constants in time.h to x86-64 time.c. The code gets significantly easier to understand. Signed-off-by: Vojtech Pavlik <vojtech@suse.cz> Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Vojtech Pavlik
Linus Torvalds
parent
e30db3e699
commit
4221133845
@ -56,6 +56,13 @@ DEFINE_SPINLOCK(i8253_lock);
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int nohpet __initdata = 0;
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static int notsc __initdata = 0;
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#define USEC_PER_TICK (USEC_PER_SEC / HZ)
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#define NSEC_PER_TICK (NSEC_PER_SEC / HZ)
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#define FSEC_PER_TICK (FSEC_PER_SEC / HZ)
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#define NS_SCALE 10 /* 2^10, carefully chosen */
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#define US_SCALE 32 /* 2^32, arbitralrily chosen */
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unsigned int cpu_khz; /* TSC clocks / usec, not used here */
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static unsigned long hpet_period; /* fsecs / HPET clock */
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unsigned long hpet_tick; /* HPET clocks / interrupt */
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@ -88,7 +95,7 @@ static inline unsigned int do_gettimeoffset_tsc(void)
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t = get_cycles_sync();
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if (t < vxtime.last_tsc)
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t = vxtime.last_tsc; /* hack */
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x = ((t - vxtime.last_tsc) * vxtime.tsc_quot) >> 32;
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x = ((t - vxtime.last_tsc) * vxtime.tsc_quot) >> US_SCALE;
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return x;
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}
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@ -96,7 +103,7 @@ static inline unsigned int do_gettimeoffset_hpet(void)
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{
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/* cap counter read to one tick to avoid inconsistencies */
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unsigned long counter = hpet_readl(HPET_COUNTER) - vxtime.last;
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return (min(counter,hpet_tick) * vxtime.quot) >> 32;
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return (min(counter,hpet_tick) * vxtime.quot) >> US_SCALE;
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}
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unsigned int (*do_gettimeoffset)(void) = do_gettimeoffset_tsc;
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@ -116,7 +123,7 @@ void do_gettimeofday(struct timeval *tv)
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seq = read_seqbegin(&xtime_lock);
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sec = xtime.tv_sec;
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usec = xtime.tv_nsec / 1000;
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usec = xtime.tv_nsec / NSEC_PER_USEC;
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/* i386 does some correction here to keep the clock
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monotonous even when ntpd is fixing drift.
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@ -127,14 +134,14 @@ void do_gettimeofday(struct timeval *tv)
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in arch/x86_64/kernel/vsyscall.c and export all needed
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variables in vmlinux.lds. -AK */
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t = (jiffies - wall_jiffies) * (1000000L / HZ) +
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t = (jiffies - wall_jiffies) * USEC_PER_TICK +
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do_gettimeoffset();
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usec += t;
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} while (read_seqretry(&xtime_lock, seq));
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tv->tv_sec = sec + usec / 1000000;
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tv->tv_usec = usec % 1000000;
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tv->tv_sec = sec + usec / USEC_PER_SEC;
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tv->tv_usec = usec % USEC_PER_SEC;
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}
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EXPORT_SYMBOL(do_gettimeofday);
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@ -155,8 +162,8 @@ int do_settimeofday(struct timespec *tv)
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write_seqlock_irq(&xtime_lock);
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nsec -= do_gettimeoffset() * 1000 +
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(jiffies - wall_jiffies) * (NSEC_PER_SEC/HZ);
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nsec -= do_gettimeoffset() * NSEC_PER_USEC +
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(jiffies - wall_jiffies) * NSEC_PER_TICK;
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wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
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wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
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@ -286,7 +293,7 @@ unsigned long long monotonic_clock(void)
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this_offset = hpet_readl(HPET_COUNTER);
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} while (read_seqretry(&xtime_lock, seq));
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offset = (this_offset - last_offset);
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offset *= (NSEC_PER_SEC/HZ) / hpet_tick;
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offset *= NSEC_PER_TICK / hpet_tick;
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} else {
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do {
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seq = read_seqbegin(&xtime_lock);
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@ -295,6 +302,7 @@ unsigned long long monotonic_clock(void)
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base = monotonic_base;
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} while (read_seqretry(&xtime_lock, seq));
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this_offset = get_cycles_sync();
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/* FIXME: 1000 or 1000000? */
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offset = (this_offset - last_offset)*1000 / cpu_khz;
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}
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return base + offset;
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@ -380,7 +388,7 @@ void main_timer_handler(struct pt_regs *regs)
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}
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monotonic_base +=
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(offset - vxtime.last)*(NSEC_PER_SEC/HZ) / hpet_tick;
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(offset - vxtime.last) * NSEC_PER_TICK / hpet_tick;
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vxtime.last = offset;
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#ifdef CONFIG_X86_PM_TIMER
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@ -389,24 +397,25 @@ void main_timer_handler(struct pt_regs *regs)
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#endif
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} else {
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offset = (((tsc - vxtime.last_tsc) *
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vxtime.tsc_quot) >> 32) - (USEC_PER_SEC / HZ);
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vxtime.tsc_quot) >> US_SCALE) - USEC_PER_TICK;
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if (offset < 0)
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offset = 0;
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if (offset > (USEC_PER_SEC / HZ)) {
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lost = offset / (USEC_PER_SEC / HZ);
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offset %= (USEC_PER_SEC / HZ);
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if (offset > USEC_PER_TICK) {
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lost = offset / USEC_PER_TICK;
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offset %= USEC_PER_TICK;
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}
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/* FIXME: 1000 or 1000000? */
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monotonic_base += (tsc - vxtime.last_tsc) * 1000000 / cpu_khz;
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vxtime.last_tsc = tsc - vxtime.quot * delay / vxtime.tsc_quot;
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if ((((tsc - vxtime.last_tsc) *
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vxtime.tsc_quot) >> 32) < offset)
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vxtime.tsc_quot) >> US_SCALE) < offset)
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vxtime.last_tsc = tsc -
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(((long) offset << 32) / vxtime.tsc_quot) - 1;
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(((long) offset << US_SCALE) / vxtime.tsc_quot) - 1;
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}
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if (lost > 0) {
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@ -466,16 +475,15 @@ static irqreturn_t timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
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}
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static unsigned int cyc2ns_scale __read_mostly;
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#define CYC2NS_SCALE_FACTOR 10 /* 2^10, carefully chosen */
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static inline void set_cyc2ns_scale(unsigned long cpu_khz)
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{
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cyc2ns_scale = (1000000 << CYC2NS_SCALE_FACTOR)/cpu_khz;
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cyc2ns_scale = (NSEC_PER_MSEC << NS_SCALE) / cpu_khz;
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}
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static inline unsigned long long cycles_2_ns(unsigned long long cyc)
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{
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return (cyc * cyc2ns_scale) >> CYC2NS_SCALE_FACTOR;
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return (cyc * cyc2ns_scale) >> NS_SCALE;
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}
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unsigned long long sched_clock(void)
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@ -488,7 +496,7 @@ unsigned long long sched_clock(void)
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Disadvantage is a small drift between CPUs in some configurations,
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but that should be tolerable. */
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if (__vxtime.mode == VXTIME_HPET)
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return (hpet_readl(HPET_COUNTER) * vxtime.quot) >> 32;
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return (hpet_readl(HPET_COUNTER) * vxtime.quot) >> US_SCALE;
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#endif
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/* Could do CPU core sync here. Opteron can execute rdtsc speculatively,
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@ -631,7 +639,7 @@ static int time_cpufreq_notifier(struct notifier_block *nb, unsigned long val,
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cpu_khz = cpufreq_scale(cpu_khz_ref, ref_freq, freq->new);
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if (!(freq->flags & CPUFREQ_CONST_LOOPS))
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vxtime.tsc_quot = (1000L << 32) / cpu_khz;
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vxtime.tsc_quot = (USEC_PER_MSEC << US_SCALE) / cpu_khz;
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}
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set_cyc2ns_scale(cpu_khz_ref);
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@ -823,8 +831,7 @@ static int hpet_init(void)
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if (hpet_period < 100000 || hpet_period > 100000000)
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return -1;
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hpet_tick = (1000000000L * (USEC_PER_SEC / HZ) + hpet_period / 2) /
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hpet_period;
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hpet_tick = (FSEC_PER_TICK + hpet_period / 2) / hpet_period;
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hpet_use_timer = (id & HPET_ID_LEGSUP);
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@ -898,7 +905,7 @@ void __init time_init(void)
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-xtime.tv_sec, -xtime.tv_nsec);
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if (!hpet_init())
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vxtime_hz = (1000000000000000L + hpet_period / 2) / hpet_period;
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vxtime_hz = (FSEC_PER_SEC + hpet_period / 2) / hpet_period;
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else
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vxtime.hpet_address = 0;
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@ -927,8 +934,8 @@ void __init time_init(void)
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vxtime_hz / 1000000, vxtime_hz % 1000000, timename, gtod);
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printk(KERN_INFO "time.c: Detected %d.%03d MHz processor.\n",
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cpu_khz / 1000, cpu_khz % 1000);
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vxtime.quot = (1000000L << 32) / vxtime_hz;
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vxtime.tsc_quot = (1000L << 32) / cpu_khz;
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vxtime.quot = (USEC_PER_SEC << US_SCALE) / vxtime_hz;
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vxtime.tsc_quot = (USEC_PER_MSEC << US_SCALE) / cpu_khz;
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vxtime.last_tsc = get_cycles_sync();
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setup_irq(0, &irq0);
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