-
Notifications
You must be signed in to change notification settings - Fork 0
/
pic8259.c
82 lines (68 loc) · 2.55 KB
/
pic8259.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
#include "pic8259.h"
#include "io.h"
#include "log.h"
#include "string.h"
#define PIC1_BASE 0x20 /* IO base address for master PIC */
#define PIC2_BASE 0xA0 /* IO base address for slave PIC */
#define PIC1_COMMAND PIC1_BASE
#define PIC1_DATA (PIC1_BASE+1)
#define PIC2_COMMAND PIC2_BASE
#define PIC2_DATA (PIC2_BASE+1)
#define ICW1_ICW4 0x01 /* ICW4 (not) needed */
#define ICW1_SINGLE 0x02 /* Single (cascade) mode */
#define ICW1_INTERVAL4 0x04 /* Call address interval 4 (8) */
#define ICW1_LEVEL 0x08 /* Level triggered (edge) mode */
#define ICW1_INIT 0x10 /* Initialization - required! */
#define ICW4_8086 0x01 /* 8086/88 (MCS-80/85) mode */
#define ICW4_AUTO 0x02 /* Auto (normal) EOI */
#define ICW4_BUF_SLAVE 0x08 /* Buffered mode/slave */
#define ICW4_BUF_MASTER 0x0C /* Buffered mode/master */
#define ICW4_SFNM 0x10 /* Special fully nested (not) */
#define PIC_ACK 0x20
/*
reinitialize the PIC controllers, giving them specified vector offsets
rather than 8h and 70h, as configured by default
arguments:
offset1 - vector offset for master PIC
vectors on the master become offset1..offset1+7
offset2 - same for slave PIC: offset2..offset2+7
*/
void PicRemap(int offset1, int offset2)
{
unsigned char a1, a2;
a1 = inb(PIC1_DATA); // save masks
a2 = inb(PIC2_DATA);
outb(PIC1_COMMAND, ICW1_INIT | ICW1_ICW4); // starts the initialization sequence (in cascade mode)
outb(PIC2_COMMAND, ICW1_INIT | ICW1_ICW4);
outb(PIC1_DATA, offset1); // ICW2: Master PIC vector offset
outb(PIC2_DATA, offset2); // ICW2: Slave PIC vector offset
outb(PIC1_DATA, 4); // ICW3: tell Master PIC that there is a slave PIC at IRQ2 (0000 0100)
outb(PIC2_DATA, 2); // ICW3: tell Slave PIC its cascade identity (0000 0010)
outb(PIC1_DATA, ICW4_8086);
outb(PIC2_DATA, ICW4_8086);
outb(PIC1_DATA, a1); // restore saved masks.
outb(PIC2_DATA, a2);
}
void PicSetMask(unsigned char mask1, unsigned char mask2) {
outb(PIC1_DATA, mask1);
outb(PIC2_DATA, mask2);
}
void PicInit() {
PicRemap(PIC1_START_INTERRUPT, PIC2_START_INTERRUPT);
}
/** PicAck:
* Acknowledges an interrupt from either PIC 1 or PIC 2.
*
* @param num The number of the interrupt
*/
void PicAck(unsigned int interrupt)
{
if (interrupt < PIC1_START_INTERRUPT || interrupt > PIC2_END_INTERRUPT) {
return;
}
if (interrupt < PIC2_START_INTERRUPT) {
outb(PIC1_COMMAND, PIC_ACK);
} else {
outb(PIC2_COMMAND, PIC_ACK);
}
}