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pit ticks each ms

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This commit is contained in:
rami 2024-07-02 15:36:47 -04:00
parent 57a6d51e68
commit 3e127f4686
3 changed files with 6 additions and 2 deletions
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1
Makefile
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@ -20,6 +20,7 @@ ISO := Hazel.iso
CFLAGS := -ffreestanding -Wall -Wextra -Werror -I $(INCLUDEDIR) -I lib
LDFLAGS := -ffreestanding -nostdlib -lgcc -T kernel/kernel.ld
QEMUFLAGS := -cdrom $(BUILDDIR)/$(ISO) \
-d int \
-serial stdio
$(BUILDDIR)/$(KIMG): $(KOBJ) $(LOBJ)

3
include/kernel/pit.h
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@ -7,12 +7,13 @@
#define PIT_MODE_CMD 0x43
#define PIT_MODE0 0
#define PIT_MODE2 (2<<1)
#define PIT_LOBYTE (1<<4)
#define PIT_LOHIGH (3<<4)
#define PIT_CHAN0 0
#define PIT_FREQUENCY 1193182
#define DESIRED_FREQUENCY 100
#define DESIRED_FREQUENCY 1000
#define DIVISOR (PIT_FREQUENCY/DESIRED_FREQUENCY)
void pit_init(void);

4
kernel/pit.c
View File

@ -6,14 +6,16 @@
extern kernel_ctx_t ctx;
void pit_init(void) {
outb(PIT_MODE_CMD, PIT_CHAN0 | PIT_LOBYTE | PIT_MODE0);
outb(PIT_MODE_CMD, PIT_CHAN0 | PIT_LOHIGH | PIT_MODE2);
outb(PIT_CHAN0_DATA, (uint8_t)(DIVISOR & 0xff));
outb(PIT_CHAN0_DATA, (uint8_t)((DIVISOR & 0xff00) >> 8));
}
void pit_handler(void) {
ctx.ticks++;
outb(PIT_CHAN0_DATA, (uint8_t)(DIVISOR & 0xff));
outb(PIT_CHAN0_DATA, (uint8_t)((DIVISOR & 0xff00) >> 8));
pic_send_eoi(0);
}