arch: i386: add PIC register support

Add functions that let the OS read the internal state registers of the
8259 PIC.

Signed-off-by: Danny Holman <dholman@gymli.xyz>

1 files changed, 14 insertions, 0 deletions

diff --git a/arch/i386/boot/pic.c b/arch/i386/boot/pic.c
index f103b92..607023c 100644
--- a/arch/i386/boot/pic.c
+++ b/arch/i386/boot/pic.c
@@ -22,6 +22,20 @@ void pic_remap(void) {
         outb(PIC2_DATA, a2);
 }
 
+static uint16_t __pic_get_irq_reg(int ocw3) {
+        outb(PIC1_COMMAND, ocw3);
+        outb(PIC2_COMMAND, ocw3);
+        return (inb(PIC2_COMMAND) << 8) | inb(PIC1_COMMAND);
+}
+
+uint16_t pic_get_irr(void) {
+        return __pic_get_irq_reg(PIC_READ_IRR);
+}
+
+uint16_t pic_get_isr(void) {
+        return __pic_get_irq_reg(PIC_READ_ISR);
+}
+
 void irq_set_mask(uint8_t irq) {
         uint16_t port;
         uint8_t data;