1 files changed, 97 insertions, 0 deletions
diff --git a/kernel/arch/i386/pic.cpp b/kernel/arch/i386/pic.cpp
new file mode 100644
index 0000000..78cbcf8
--- /dev/null
+++ b/kernel/arch/i386/pic.cpp
@@ -0,0 +1,97 @@
+#include <io.h>
+#include <arch/i386/pic.h>
+#include <stdint.h>
+#include <arch/i386/pic.h>
+
+#define PIC1 0x20
+#define PIC2 0xA0
+#define PIC1_CMD PIC1
+#define PIC1_DATA (PIC1 + 1)
+#define PIC2_CMD PIC2
+#define PIC2_DATA (PIC2 + 1)
+#define PIC_READ_IRR 0x0a    // OCW3 irq ready next CMD read
+#define PIC_READ_ISR 0x0b    // OCW3 irq service next CMD read
+
+#define PIC_EOI 0x20
+
+// pic reinitialization constants
+#define ICW1_ICW4 0x01 // indicates icw4 will be present
+#define ICW1_SINGLE 0x02 // single cascade mode
+#define ICW1_INTERVAL4 0x04 // call address interval 4
+#define ICW1_LEVEL 0x08 // level triggered (edge) mode
+#define ICW1_INIT 0x10 // initialization
+
+#define ICW4_8086 0x01 // 8086 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)
+
+void pic_send_eoi(unsigned char irq) {
+    if (irq >= 8) {
+        outb(PIC2_CMD, PIC_EOI);
+    }
+    outb(PIC1_CMD, PIC_EOI);
+}
+
+// offset 1 is for master, offset 2 is for slave
+void pic_remap(int offset1, int offset2) {
+    unsigned char a1, a2;
+
+    a1 = inb(PIC1_DATA); // save masks
+    a2 = inb(PIC2_DATA);
+
+    outb(PIC1_CMD, ICW1_INIT | ICW1_ICW4); // starts initialization in cascade mode
+    io_wait();
+    outb(PIC2_CMD, ICW1_INIT | ICW1_ICW4);
+    io_wait();
+    outb(PIC1_DATA, offset1); // icw2: master and slave vector offset set
+    io_wait();
+    outb(PIC2_DATA, offset2);
+    io_wait();
+    outb(PIC1_DATA, 4); // tells master pic theres a slave pic at irq2
+    io_wait();
+    outb(PIC2_DATA, 2); // tells slave pic its cascade identity
+    io_wait();
+
+    outb(PIC1_DATA, ICW4_8086);
+    io_wait();
+    outb(PIC2_DATA, ICW4_8086);
+    io_wait();
+
+    outb(PIC1_DATA, a1); // restore masks
+    outb(PIC2_DATA, a2);
+
+    for (char i = 0; i < 15; i++)
+	{
+		irq_set_mask(i);
+	}
+}
+
+void irq_set_mask(unsigned char irq) {
+    uint16_t port;
+    uint8_t value;
+
+    if (irq < 8) {
+        port = PIC1_DATA;
+    } else {
+        port = PIC2_DATA;
+        irq -= 8;
+    }
+    value = inb(port) | (1 << irq);
+    outb(port, value);
+}
+
+void irq_clear_mask(unsigned char irq) {
+    uint16_t port;
+    uint8_t value;
+
+    if (irq < 8) {
+        port = PIC1_DATA;
+    } else {
+        port = PIC2_DATA;
+        irq -= 8;
+    }
+    value = inb(port) & ~(1 << irq);
+    outb(port, value);
+}
+\ No newline at end of file