57 lines
1.3 KiB
C
57 lines
1.3 KiB
C
#include <signal.h>
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#include <stdlib.h>
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#include <sys/time.h>
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#include "clock.h"
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#include "simulation.h"
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static uint8_t clock_counter_250ms = 0;
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static uint8_t clock_counter_1s = 0;
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volatile uint8_t clock_flag = 0;
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static bool clock_initialised = false;
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#define SIM_CLOCK_SLOWDOWN 50
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static void timer2_isr(int cause, siginfo_t *HowCome, void *ucontext)
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{
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if (!sim_interrupts) return;
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sim_interrupts = false;
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// 1/4 second tick
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if (++clock_counter_250ms == 250 / SIM_CLOCK_SLOWDOWN) {
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clock_flag |= CLOCK_FLAG_250MS;
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clock_counter_250ms = 0;
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if (++clock_counter_1s == 4) {
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clock_flag |= CLOCK_FLAG_1S;
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clock_counter_1s = 0;
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}
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}
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sim_interrupts = true;
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}
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void clock_setup(void)
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{
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struct itimerval itimer;
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struct sigaction sa;
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long unsigned int usec = 1000 * SIM_CLOCK_SLOWDOWN;
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sim_info("clock_setup: simulate timer 2 ISR at %luus", usec);
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sa.sa_sigaction = timer2_isr;
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sigemptyset(&sa.sa_mask);
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sa.sa_flags = SA_SIGINFO;
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if (sigaction(SIGPROF, &sa, 0)) {
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sim_error("sigaction");
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}
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itimer.it_interval.tv_sec = 0;
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itimer.it_interval.tv_usec = 1000 * SIM_CLOCK_SLOWDOWN;
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itimer.it_value.tv_sec = 0;
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itimer.it_value.tv_usec = 1000 * SIM_CLOCK_SLOWDOWN;
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setitimer(ITIMER_PROF, &itimer, NULL);
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clock_initialised = true;
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}
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