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27 lines
658 B
27 lines
658 B
#include "timer.h"
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#include "isr.h"
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#include "ports.h"
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#include "../libc/function.h"
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uint32_t tick = 0;
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static void timer_callback(registers_t *regs) {
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tick++;
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UNUSED(regs);
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}
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void init_timer(uint32_t freq) {
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/* Install the function we just wrote */
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register_interrupt_handler(IRQ0, timer_callback);
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/* Get the PIT value: hardware clock at 1193180 Hz */
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uint32_t divisor = 1193180 / freq;
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uint8_t low = (uint8_t)(divisor & 0xFF);
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uint8_t high = (uint8_t)( (divisor >> 8) & 0xFF);
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/* Send the command */
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port_byte_out(0x43, 0x36); /* Command port */
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port_byte_out(0x40, low);
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port_byte_out(0x40, high);
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}
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