From c0a8113ba0b7cd6984cc685ec63f79bef3bc9899 Mon Sep 17 00:00:00 2001
From: Aleksa Vuckovic <aleksav013@gmail.com>
Date: Tue, 2 Aug 2022 18:59:51 +0200
Subject: framebuffer multiboot2

---
 kernel/header.S | 43 +++++++++++++++++++++++++++++++++----------
 1 file changed, 33 insertions(+), 10 deletions(-)

(limited to 'kernel/header.S')

diff --git a/kernel/header.S b/kernel/header.S
index 5a57741..bbcb9be 100644
--- a/kernel/header.S
+++ b/kernel/header.S
@@ -1,17 +1,40 @@
+// multiboot tags
+.set TAG_END,		0
+.set TAG_FRAMEBUFFER,	5
+
+// multiboot flags
+.set TAG_REQUIRED,	0
+.set TAG_OPTIONAL,	1
+
+# multiboot2 header constants
+.set MAGIC,		0xe85250d6
+.set ARCH,		0
+.set HEADER_LENGTH,	(header_end - header_start)
+.set CHECKSUM,		0x100000000 - (MAGIC + ARCH + HEADER_LENGTH)
+
 .section .multiboot_header, "a"
 .align 4
 header_start:
-	# magic number
-	.long 0xe85250d6 # multiboot2
-	# architecture
-	.long 0 # protected mode i386
-	# header length
-	.long (header_end - header_start)
-	# checksum
-	.long 0x100000000 - (0xe85250d6 + 0 + (header_end - header_start))
+	# magic
+	.align 8
+	.long MAGIC
+	.long ARCH
+	.long HEADER_LENGTH
+	.long CHECKSUM
+
+	# framebuffer
+	.align 8
+	.word TAG_FRAMEBUFFER
+	.word TAG_REQUIRED
+	.long 20
+	.long 1024
+	.long 768
+	.long 32
 
 	# end tag
-	.word 0
-	.word 0
+	.align 8
+	.word TAG_END
+	.word TAG_REQUIRED
 	.long 8
+
 header_end:
-- 
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