setup pic

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 24 insertions, 0 deletions

diff --git a/main.c b/main.c
index ed871df..5ef38cf 100644
--- a/main.c
+++ b/main.c
@@ -45,11 +45,34 @@ static void set_realmode_int(int vec, void *p)
 	realmode_idt[vec * 2 + 1] = flat_to_seg16((uintptr_t) p);
 }
 
+static void setup_pic(void)
+{
+    /* Send ICW1 (select OCW1 + will send ICW4) */
+    outb(0x20, 0x11);
+    outb(0xa0, 0x11);
+    /* Send ICW2 (base irqs: 0x08-0x0f for irq0-7, 0x70-0x77 for irq8-15) */
+    outb(0x21, 8);
+    outb(0xa1, 0x70);
+    /* Send ICW3 (cascaded pic ids) */
+    outb(0x21, 0x04);
+    outb(0xa1, 0x02);
+    /* Send ICW4 (enable 8086 mode) */
+    outb(0x21, 0x01);
+    outb(0xa1, 0x01);
+    /* Mask all irqs (except cascaded PIC2 irq) */
+    outb(0x21, ~(1 << 2));
+    outb(0xa1, ~0);
+}
+
 static void setup_idt(void)
 {
 	int i;
 	for (i = 0; i < 0x1f; i++)
 		set_realmode_int(i, bios_intfake);
+	for (i = 8; i < 16; i++)
+		set_realmode_int(i, bios_irq);
+	for (i = 0x70; i < 0x78; i++)
+		set_realmode_int(i, bios_irq);
 	set_realmode_int(0x10, bios_int10);
 	set_realmode_int(0x15, bios_int15);
 }
@@ -57,6 +80,7 @@ static void setup_idt(void)
 int main(void)
 {
 	make_bios_writable();
+	setup_pic();
 	setup_idt();
 	// extract_acpi();
 	// extract_e820();