From ad8ab9b672d9f040f84b9933878b22fb291e41e7 Mon Sep 17 00:00:00 2001
From: Aiden Gall <aiden@aidengall.xyz>
Date: Sun, 26 May 2024 22:22:14 +0100
Subject: add primitive vga terminal output

---
 boot/boot.asm | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

(limited to 'boot/boot.asm')

diff --git a/boot/boot.asm b/boot/boot.asm
index eedde07..62f80f8 100644
--- a/boot/boot.asm
+++ b/boot/boot.asm
@@ -1,5 +1,7 @@
 format ELF64
 
+extrn kmain
+
 PML4_TABLE = 0x1000
 E820_MMAP  = 0xf000
 
@@ -9,7 +11,7 @@ include 'bios.inc'
 include 'page.inc'
 include 'segdesc.inc'
 
-section '.text.boot' executable
+section '.boot' executable writeable
 
 org 0x7c00
 use16
@@ -104,12 +106,17 @@ longmode:
 	xor ecx, ecx
 	xor edx, edx
 	xor edi, edi
+	xor esi, esi
 
 	; put stack at top of addressable memory
 	mov esp, 0x200000
 	mov ebp, esp
 
-	jmp 0x100000
+	; manually encoded 'jmp rel32', fasm throws an 'invalid use of symbol'
+	; error when generating code for a jmp to an external symbol after
+	; setting code origin with 'org' directive or a 'virtual at X' block.
+	db 0xe9
+	dd kmain-$-4
 
 align 4
 dw 0
-- 
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