Initial commit

code/ioapic_redtbl_example.cpp

@@ -0,0 +1,26 @@
+// Excerpt from the IoAPic::initializeREDTBL function
+void IoApic::initializeREDTBL() {
+    // GSI2 belongs to the PIT in many systems
+    auto gsi = GlobalSystemInterrupt(2);
+    IrqOverride *override = getOverride(gsi);
+
+    REDTBLEntry redtblEntry{};
+    redtblEntry.deliveryMode    = REDTBLEntry::DeliveryMode::FIXED;
+    redtblEntry.destinationMode = REDTBLEntry::DestinationMode::PHYSICAL;
+    redtblEntry.isMasked        = true;
+    redtblEntry.destination     = LocalApic::getId(); // Redirect to BSP
+
+    if (override != nullptr) {
+        // Apply any information provided by an interrupt override
+        redtblEntry.vector      = override->source + 32;
+        redtblEntry.pinPolarity = override->polarity;
+        redtblEntry.triggerMode = override->trigger;
+    } else {
+        // Apply PC/AT compatible ISA bus defaults
+        redtblEntry.vector      = gsi + 32;
+        redtblEntry.pinPolarity = REDTBLEntry::PinPolarity::HIGH;
+        redtblEntry.triggerMode = REDTBLEntry::TriggerMode::EDGE;
+    }
+
+    writeREDTBL(gsi, redtblEntry);
+}