- tsc_ctr_switch is made cpu local - although an x86 specific variable it must be declared globaly as the cpulocal implementation does not allow otherwise
236 lines
5.7 KiB
C
236 lines
5.7 KiB
C
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/* i386-specific clock functions. */
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#include <machine/ports.h>
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#include <minix/portio.h>
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#include "kernel/kernel.h"
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#include "kernel/clock.h"
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#include "kernel/proc.h"
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#include <minix/u64.h>
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#include "glo.h"
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#ifdef CONFIG_APIC
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#include "apic.h"
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#endif
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#include "spinlock.h"
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#define CLOCK_ACK_BIT 0x80 /* PS/2 clock interrupt acknowledge bit */
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/* Clock parameters. */
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#define COUNTER_FREQ (2*TIMER_FREQ) /* counter frequency using square wave */
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#define LATCH_COUNT 0x00 /* cc00xxxx, c = channel, x = any */
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#define SQUARE_WAVE 0x36 /* ccaammmb, a = access, m = mode, b = BCD */
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/* 11x11, 11 = LSB then MSB, x11 = sq wave */
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#define TIMER_FREQ 1193182 /* clock frequency for timer in PC and AT */
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#define TIMER_COUNT(freq) (TIMER_FREQ/(freq)) /* initial value for counter*/
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PRIVATE irq_hook_t pic_timer_hook; /* interrupt handler hook */
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PRIVATE unsigned probe_ticks;
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PRIVATE u64_t tsc0, tsc1;
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#define PROBE_TICKS (system_hz / 10)
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PRIVATE unsigned tsc_per_ms[CONFIG_MAX_CPUS];
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/*===========================================================================*
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* init_8235A_timer *
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*===========================================================================*/
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PUBLIC int init_8253A_timer(const unsigned freq)
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{
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/* Initialize channel 0 of the 8253A timer to, e.g., 60 Hz,
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* and register the CLOCK task's interrupt handler to be run
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* on every clock tick.
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*/
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outb(TIMER_MODE, SQUARE_WAVE); /* run continuously */
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outb(TIMER0, (TIMER_COUNT(freq) & 0xff)); /* timer low byte */
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outb(TIMER0, TIMER_COUNT(freq) >> 8); /* timer high byte */
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return OK;
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}
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/*===========================================================================*
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* stop_8235A_timer *
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*===========================================================================*/
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PUBLIC void stop_8253A_timer(void)
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{
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/* Reset the clock to the BIOS rate. (For rebooting.) */
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outb(TIMER_MODE, 0x36);
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outb(TIMER0, 0);
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outb(TIMER0, 0);
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}
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PRIVATE int calib_cpu_handler(irq_hook_t * UNUSED(hook))
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{
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u64_t tsc;
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probe_ticks++;
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read_tsc_64(&tsc);
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if (probe_ticks == 1) {
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tsc0 = tsc;
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}
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else if (probe_ticks == PROBE_TICKS) {
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tsc1 = tsc;
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}
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/* just in case we are in an SMP single cpu fallback mode */
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BKL_UNLOCK();
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return 1;
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}
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PRIVATE void estimate_cpu_freq(void)
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{
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u64_t tsc_delta;
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u64_t cpu_freq;
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irq_hook_t calib_cpu;
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/* set the probe, we use the legacy timer, IRQ 0 */
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put_irq_handler(&calib_cpu, CLOCK_IRQ, calib_cpu_handler);
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/* just in case we are in an SMP single cpu fallback mode */
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BKL_UNLOCK();
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/* set the PIC timer to get some time */
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intr_enable();
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/* loop for some time to get a sample */
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while(probe_ticks < PROBE_TICKS) {
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intr_enable();
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}
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intr_disable();
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/* just in case we are in an SMP single cpu fallback mode */
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BKL_LOCK();
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/* remove the probe */
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rm_irq_handler(&calib_cpu);
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tsc_delta = sub64(tsc1, tsc0);
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cpu_freq = mul64(div64u64(tsc_delta, PROBE_TICKS - 1), make64(system_hz, 0));
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cpu_set_freq(cpuid, cpu_freq);
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BOOT_VERBOSE(cpu_print_freq(cpuid));
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}
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PUBLIC int arch_init_local_timer(unsigned freq)
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{
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#ifdef CONFIG_APIC
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/* if we know the address, lapic is enabled and we should use it */
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if (lapic_addr) {
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unsigned cpu = cpuid;
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lapic_set_timer_periodic(freq);
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tsc_per_ms[cpu] = div64u(cpu_get_freq(cpu), 1000);
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} else
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{
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BOOT_VERBOSE(printf("Initiating legacy i8253 timer\n"));
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#else
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{
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#endif
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init_8253A_timer(freq);
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estimate_cpu_freq();
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/* always only 1 cpu in the system */
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tsc_per_ms[0] = div64u(cpu_get_freq(0), 1000);
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}
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return 0;
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}
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PUBLIC void arch_stop_local_timer(void)
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{
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#ifdef CONFIG_APIC
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if (lapic_addr) {
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lapic_stop_timer();
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} else
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#endif
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{
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stop_8253A_timer();
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}
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}
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PUBLIC int arch_register_local_timer_handler(const irq_handler_t handler)
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{
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#ifdef CONFIG_APIC
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if (lapic_addr) {
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/* Using APIC, it is configured in apic_idt_init() */
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BOOT_VERBOSE(printf("Using LAPIC timer as tick source\n"));
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} else
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#endif
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{
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/* Using PIC, Initialize the CLOCK's interrupt hook. */
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pic_timer_hook.proc_nr_e = NONE;
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pic_timer_hook.irq = CLOCK_IRQ;
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put_irq_handler(&pic_timer_hook, CLOCK_IRQ, handler);
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}
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return 0;
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}
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PUBLIC void cycles_accounting_init(void)
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{
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read_tsc_64(get_cpulocal_var_ptr(tsc_ctr_switch));
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}
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PUBLIC void context_stop(struct proc * p)
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{
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u64_t tsc, tsc_delta;
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u64_t * __tsc_ctr_switch = get_cpulocal_var_ptr(tsc_ctr_switch);
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read_tsc_64(&tsc);
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tsc_delta = sub64(tsc, *__tsc_ctr_switch);
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p->p_cycles = add64(p->p_cycles, tsc_delta);
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/*
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* deduct the just consumed cpu cycles from the cpu time left for this
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* process during its current quantum. Skip IDLE and other pseudo kernel
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* tasks
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*/
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if (p->p_endpoint >= 0) {
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#if DEBUG_RACE
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make_zero64(p->p_cpu_time_left);
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#else
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/* if (tsc_delta < p->p_cpu_time_left) in 64bit */
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if (tsc_delta.hi < p->p_cpu_time_left.hi ||
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(tsc_delta.hi == p->p_cpu_time_left.hi &&
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tsc_delta.lo < p->p_cpu_time_left.lo))
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p->p_cpu_time_left = sub64(p->p_cpu_time_left, tsc_delta);
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else {
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make_zero64(p->p_cpu_time_left);
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}
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#endif
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}
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/*
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* This function is called only if we switch from kernel to user or idle
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* or back. Therefore this is a perfect location to place the big kernel
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* lock which will hopefully disappear soon.
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*
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* If we stop accounting for KERNEL we must unlock the BKL. If account
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* for IDLE we must not hold the lock
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*/
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if (p == proc_addr(KERNEL)) {
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read_tsc_64(&tsc);
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p->p_cycles = add64(p->p_cycles, sub64(tsc, *__tsc_ctr_switch));
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BKL_UNLOCK();
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} else {
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BKL_LOCK();
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read_tsc_64(&tsc);
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p->p_cycles = add64(p->p_cycles, sub64(tsc, *__tsc_ctr_switch));
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}
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*__tsc_ctr_switch = tsc;
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}
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PUBLIC void context_stop_idle(void)
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{
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context_stop(proc_addr(IDLE));
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}
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PUBLIC u64_t ms_2_cpu_time(unsigned ms)
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{
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return mul64u(tsc_per_ms[cpuid], ms);
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}
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