From b3ca9af48a0d4946a08f48bc7fc0061578ed4546 Mon Sep 17 00:00:00 2001
From: Josh Holtrop <jholtrop@gmail.com>
Date: Tue, 6 Sep 2022 22:35:41 -0400
Subject: [PATCH] Disable PIC

---
 src/hos/cpu.d   | 10 ++++++++++
 src/hulk/hulk.d |  2 ++
 src/hulk/pic.d  | 16 ++++++++++++++++
 3 files changed, 28 insertions(+)
 create mode 100644 src/hulk/pic.d

diff --git a/src/hos/cpu.d b/src/hos/cpu.d
index 9fb02ad..10ee1ac 100644
--- a/src/hos/cpu.d
+++ b/src/hos/cpu.d
@@ -40,6 +40,11 @@ ulong read_cr4()
     return __asm!ulong("mov %cr4, %rax", "={rax}");
 }
 
+ubyte in8(ushort ioaddr)
+{
+    return __asm!ubyte("inb %dx, %al", "={al},{dx}", ioaddr);
+}
+
 ushort in16(ushort ioaddr)
 {
     return __asm!ushort("inw %dx, %ax", "={ax},{dx}", ioaddr);
@@ -50,6 +55,11 @@ ulong in32(ushort ioaddr)
     return __asm!ulong("inl %dx, %eax", "={eax},{dx}", ioaddr);
 }
 
+void out8(ushort ioaddr, ubyte v)
+{
+    __asm("outb %al, %dx", "{dx},{al}", ioaddr, v);
+}
+
 void out16(ushort ioaddr, ushort v)
 {
     __asm("outw %ax, %dx", "{dx},{ax}", ioaddr, v);
diff --git a/src/hulk/hulk.d b/src/hulk/hulk.d
index 419d828..eab7d4b 100644
--- a/src/hulk/hulk.d
+++ b/src/hulk/hulk.d
@@ -17,6 +17,7 @@ import hulk.gdt;
 import hulk.idt;
 import hos.cpu;
 import ldc.llvmasm;
+import hulk.pic;
 
 extern extern(C) __gshared ubyte _hulk_total_size;
 
@@ -47,6 +48,7 @@ void hulk_start()
 
     hippo.initialize(&hulk_header);
     pci.initialize();
+    pic.initialize();
     sti();
 
     for (;;)
diff --git a/src/hulk/pic.d b/src/hulk/pic.d
new file mode 100644
index 0000000..ffc8ca6
--- /dev/null
+++ b/src/hulk/pic.d
@@ -0,0 +1,16 @@
+/**
+ * PIC (Programmable Interrupt Controller) functionality.
+ */
+module hulk.pic;
+
+import hos.cpu;
+
+struct pic
+{
+    public static void initialize()
+    {
+        /* Disable the PIC. */
+        out8(0xA1u, 0xFFu);
+        out8(0x21u, 0xFFu);
+    }
+}