54 lines
777 B
C++
54 lines
777 B
C++
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#include "pit.h"
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#include "tty/kterm.h"
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uint32_t pit_tick = 0;
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void pit_initialise()
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{
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asm volatile("CLI");
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printf("init PIT!\n");
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// clear mask for IRQ 0
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uint8_t value = inb(0x21) & ~(1<< 0);
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outb(0x21, value);
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io_wait();
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const int freq = 500;
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uint32_t divisor = 1193180 / freq;
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outb(PIT_COMMAND, 0x36);
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uint8_t l = (uint8_t) (divisor & 0xFF);
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uint8_t h = (uint8_t) ( (divisor>>8) & 0xff);
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outb(PIT_DATA_0, l);
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outb(PIT_DATA_0,h);
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asm volatile("STI");
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}
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void get_pit_count()
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{
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asm volatile ("CLI");
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outb(PIT_COMMAND, 0);
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uint16_t count = inb(PIT_DATA_0);
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count |= inb(PIT_DATA_0) << 8;
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printf("PIT count: 0x%x\n", count);
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asm volatile("STI");
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}
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void set_pit_count()
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{
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}
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