33 lines
576 B
C
33 lines
576 B
C
#include "timer.h"
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#include "io.h"
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#include "sys.h"
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#include "interrupts.h"
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volatile uint32_t tick = 0;
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void pit_handler(Stack *registers)
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{
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++tick;
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}
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void delay(uint32_t milliseconds)
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{
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uint32_t end = tick + milliseconds;
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while (tick < end)
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;
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}
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void pit_set_frequency(uint32_t frequency)
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{
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uint32_t divisor = PIT_FREQUENCY / frequency;
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outb(PIT_COMMAND, 0x36);
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outb(PIT_CHANNEL_0, divisor & 0xFF);
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outb(PIT_CHANNEL_0, divisor >> 8);
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}
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void timer_install(void)
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{
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irq_install_handler(0, pit_handler);
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pit_set_frequency(1000);
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}
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