73 lines
1.7 KiB
C++
73 lines
1.7 KiB
C++
#include <pic.h>
|
|
#include <common.h>
|
|
#include <string_utils.h>
|
|
#include <serial.h>
|
|
|
|
static inline void outb(UINT16 port, UINT8 val) {
|
|
ASM("outb %0, %1" : : "a"(val), "Nd"(port));
|
|
}
|
|
|
|
static inline UINT8 inb(UINT16 port) {
|
|
UINT8 ret;
|
|
ASM("inb %1, %0" : "=a"(ret) : "Nd"(port));
|
|
return ret;
|
|
}
|
|
|
|
static void pic_wait(void) {
|
|
// Small delay for slow PICs
|
|
ASM("jmp 1f\n\t1: jmp 1f\n\t1:");
|
|
}
|
|
|
|
void pic_init(void) {
|
|
serial_write("PIC: remapping 8259 PIC\n");
|
|
|
|
// Save masks
|
|
UINT8 mask1 = inb(PIC1_DATA);
|
|
UINT8 mask2 = inb(PIC2_DATA);
|
|
|
|
// ICW1: begin initialization, ICW4 needed
|
|
outb(PIC1_CMD, 0x11); pic_wait();
|
|
outb(PIC2_CMD, 0x11); pic_wait();
|
|
|
|
// ICW2: vector offset
|
|
outb(PIC1_DATA, PIC_IRQ_BASE); // IRQ 0-7 → vector 0x20-0x27
|
|
pic_wait();
|
|
outb(PIC2_DATA, PIC_IRQ_BASE + 8); // IRQ 8-15 → vector 0x28-0x2F
|
|
pic_wait();
|
|
|
|
// ICW3: cascading
|
|
outb(PIC1_DATA, 0x04); pic_wait(); // slave on IRQ 2
|
|
outb(PIC2_DATA, 0x02); pic_wait(); // cascade identity
|
|
|
|
// ICW4: 8086 mode
|
|
outb(PIC1_DATA, 0x01); pic_wait();
|
|
outb(PIC2_DATA, 0x01); pic_wait();
|
|
|
|
// Restore masks
|
|
outb(PIC1_DATA, mask1);
|
|
outb(PIC2_DATA, mask2);
|
|
|
|
serial_write("PIC: remapped IRQ 0-7 → 0x20-0x27\n");
|
|
}
|
|
|
|
void pic_send_eoi(UINT8 irq) {
|
|
if (irq >= 8) {
|
|
outb(PIC2_CMD, PIC_EOI);
|
|
}
|
|
outb(PIC1_CMD, PIC_EOI);
|
|
}
|
|
|
|
void pic_mask_irq(UINT8 irq) {
|
|
UINT16 port = (irq < 8) ? PIC1_DATA : PIC2_DATA;
|
|
UINT8 shift = irq % 8;
|
|
UINT8 mask = inb(port) | (1 << shift);
|
|
outb(port, mask);
|
|
}
|
|
|
|
void pic_unmask_irq(UINT8 irq) {
|
|
UINT16 port = (irq < 8) ? PIC1_DATA : PIC2_DATA;
|
|
UINT8 shift = irq % 8;
|
|
UINT8 mask = inb(port) & ~(1 << shift);
|
|
outb(port, mask);
|
|
}
|