From ed3ef0fdab8b0ccb57e67e3be4f8c8b7581343dd Mon Sep 17 00:00:00 2001
From: Marin Ivanov <dev@metala.org>
Date: Wed, 1 May 2024 16:34:00 +0300
Subject: boot: convert to multiboot2

---
 src/grub.cfg |  2 +-
 src/main.zig | 24 +++++++++++++++++-------
 2 files changed, 18 insertions(+), 8 deletions(-)

(limited to 'src')

diff --git a/src/grub.cfg b/src/grub.cfg
index 7904bf7..2629c03 100644
--- a/src/grub.cfg
+++ b/src/grub.cfg
@@ -1,3 +1,3 @@
 menuentry "Zig Bare Bones" {
-	multiboot /boot/kernel.elf
+	multiboot2 /boot/kernel.elf
 }
diff --git a/src/main.zig b/src/main.zig
index adef54c..de91b83 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -2,19 +2,29 @@ const debug = @import("debugcon.zig");
 
 const ALIGN = 1 << 0;
 const MEMINFO = 1 << 1;
-const MAGIC = 0x1BADB002;
-const FLAGS = ALIGN | MEMINFO;
+const MAGIC = 0xE85250D6;
+// const FLAGS = ALIGN | MEMINFO;
+const FLAGS = 0;
 
 const MultibootHeader = extern struct {
-    magic: i32,
-    flags: i32,
-    checksum: i32,
+    magic: u32,
+    flags: u32,
+    len: u32,
+    checksum: u32,
+
+    tag0: u16,
+    tag1: u16,
+    tag2: u32,
 };
 
-export const multiboot align(4) linksection(".multiboot") = MultibootHeader{
+export const multiboot2 align(4) linksection(".multiboot") = MultibootHeader{
     .magic = MAGIC,
     .flags = FLAGS,
-    .checksum = -(MAGIC + FLAGS),
+    .len = 24,
+    .checksum = 0x100000000 - (MAGIC + FLAGS + 24),
+    .tag0 = 0,
+    .tag1 = 0,
+    .tag2 = 8,
 };
 
 export fn _start() callconv(.Naked) noreturn {
-- 
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