From 18591b2770da1b2f3ed738fe4932e6319a5e9bbf Mon Sep 17 00:00:00 2001
From: maelstrom <maelstrom@noreply.git.maelstrom.dev>
Date: Wed, 24 Jul 2024 20:16:51 +0300
Subject: [PATCH] Boot sector complete

---
 boot.asm |  44 +++++++++++++++++++++++++++++++++++++++++---
 main.asm |   3 +++
 main.bin | Bin 531 -> 683 bytes
 3 files changed, 44 insertions(+), 3 deletions(-)

diff --git a/boot.asm b/boot.asm
index beb1127..126351c 100644
--- a/boot.asm
+++ b/boot.asm
@@ -1,8 +1,45 @@
 [org 0x7c00]
+section BOOTSECTOR start=7C00h
 
+OS_SEGMENT equ 0x100
+
+; https://github.com/cfenollosa/os-tutorial
 boot:
-    mov bx, HELLO_WORLD2
-    call println
+    ; Load from disk
+    mov ah, 0x02 ; read
+    mov al, 0x01 ; No of sectors (1)
+    mov cl, 0x02 ; Sector start (1 = boot sector, 2 = OS)
+    mov ch, 0x00 ; Cylinder 0
+    mov dh, 0x00 ; Head 0
+    
+    mov bx, OS_SEGMENT ; Set target segment
+    mov es, bx
+    mov bx, 0x0 ; Target offset in segment
+    
+    int 0x13      ; Send read interrupt
+    jc disk_error
+    
+    ; Now that the OS is loaded in 0x1000, let's call main!
+    jmp 0x100:0x0
+
+disk_error:
+    mov si, DISK_ERR_MSG
+    call bs_print
+    jmp $
+    
+; https://stackoverflow.com/a/53403853
+bs_print:
+    mov     ah, 0x0e            ; BIOS TTY function
+    
+    .L0:
+        lodsb
+        or      al, al
+        jnz     .J0
+        ret
+    .J0:
+    
+    int     0x10
+    jmp     .L0
 
 jmp $ ; Halt
 
@@ -10,7 +47,8 @@ jmp $ ; Halt
 
 
 ; Boot sector data
-
+DISK_ERR_MSG:
+    db 'DISK ERROR: Failed to load kernel!', 0
 
 ; Boot sector padding and magic number
 times 510-($-$$) db 0
diff --git a/main.asm b/main.asm
index 188af92..bbbfc03 100644
--- a/main.asm
+++ b/main.asm
@@ -1,6 +1,9 @@
 ; Bootloader
 %include "boot.asm"
 
+
+section KERNEL follows=BOOTSECTOR vstart=1000h
+
 main:
     mov bx, HELLO_WORLD
     call println
diff --git a/main.bin b/main.bin
index 7ca3f4e48733e6920afbdbc759f4176fa2fa196f..fe4ae114ded8add81650b9ce28f78f5193a857a9 100644
GIT binary patch
delta 104
zcmV-u0GI!h1giy8v;wdJu>!RKwg9^T0gl7F007Msas}!D0005LF?{F(0PFs=4y*{k
zbpgZ85bO5q{zOSrOCUv3QcqGkAVy(nY-MC1bZ;PRZ((F0Yh`k7Wo#j_u}uMyz+MGa
Ks=JyHkprk72`GC2

delta 38
ucmZ3@I+=xe_pF-9%uFjbCIvH!hOT=3&m%P_CtpXQJijO>MNz@Zg#iE_zzydB