From dfe4a33865ef01c5068804f77da844cdebd87f00 Mon Sep 17 00:00:00 2001
From: kotorifan <kotorifan05@gmail.com>
Date: Sat, 31 Jan 2026 13:32:57 +0100
Subject: Added stage 1 of the bootloader + make.sh

---
 src/boot.common.asm       |  0
 src/boot.stage1.asm       | 56 +++++++++++++++++++++++++++++++++++++++++++++++
 src/boot.stage1.print.asm | 21 ++++++++++++++++++
 src/boot.stage2.asm       |  2 ++
 src/boot.stage2.gdt32.asm | 29 ++++++++++++++++++++++++
 5 files changed, 108 insertions(+)
 create mode 100644 src/boot.common.asm
 create mode 100644 src/boot.stage1.asm
 create mode 100644 src/boot.stage1.print.asm
 create mode 100644 src/boot.stage2.asm
 create mode 100644 src/boot.stage2.gdt32.asm

(limited to 'src')

diff --git a/src/boot.common.asm b/src/boot.common.asm
new file mode 100644
index 0000000..e69de29
diff --git a/src/boot.stage1.asm b/src/boot.stage1.asm
new file mode 100644
index 0000000..c5bab26
--- /dev/null
+++ b/src/boot.stage1.asm
@@ -0,0 +1,56 @@
+    ;; boot.stage1.asm
+
+    %include "boot.common.asm"
+    %include "boot.stage1.print.asm"
+    [org 0x7c00]    
+    [bits 16]
+
+    %define READ_SECTORS_NUM 64
+    %define BOOT_LOAD_ADDR 0x7c00
+    %define SECTOR_SIZE 512
+
+    entry _start
+
+_start: 
+    ;; Disable interrupts
+    cli                         
+
+    ;; Setup segment registers
+    xor ax, ax
+    mov ds, ax
+    mov es, ax  
+    mov ss, ax
+
+    ;; Adjust Stack
+    mov sp, _start
+
+    mov si, [disk_addr_packet]
+    mov ah, 0x42                ; BIOS extended read function
+    mov dl, 0x80                ; Drive number
+    int 0x13                    ; BIOS disk services
+    jc _disk_read_err
+    
+    jmp 0x0000:0x7e00
+
+_disk_read_err: 
+    hlt
+    jmp _disk_read_err
+
+_end:
+    hlt 
+    jmp _end
+
+disk_read_err_msg: db "Failed to read disk", 13, 10, 0
+disk_read_success_msg: db "Read the disk successfully", 13, 10, 0
+disk_addr_packet:  
+    db 0x10 
+    db 0x0
+DAP_sectors_num:    
+    dw READ_SECTORS_NUM         ; Number of read sectors
+    dd (BOOT_LOAD_ADDR + SECTOR_SIZE) ; Destination address
+    dq 1                              ; First sector after the boot sector
+
+    ;; Padding and magic number
+    times 510 - ($ - $$) db 0
+    dw 0xaa55
+    
diff --git a/src/boot.stage1.print.asm b/src/boot.stage1.print.asm
new file mode 100644
index 0000000..106a4df
--- /dev/null
+++ b/src/boot.stage1.print.asm
@@ -0,0 +1,21 @@
+    ;; boot.stage1.print.asm
+
+    [bits 16]
+_print_string:  
+    pusha
+    mov ah, 0x0e
+
+_print_string_loop:     
+    cmp byte [bx], 0
+    je print_string_return
+    
+    mov al, [bx]
+    int 0x10
+    
+    inc bx 
+    jmp print_string_loop
+
+_print_string_return:   
+    popa
+    ret
+    align 4
diff --git a/src/boot.stage2.asm b/src/boot.stage2.asm
new file mode 100644
index 0000000..7eeefe7
--- /dev/null
+++ b/src/boot.stage2.asm
@@ -0,0 +1,2 @@
+    ;; boot.stage2.asm
+    
diff --git a/src/boot.stage2.gdt32.asm b/src/boot.stage2.gdt32.asm
new file mode 100644
index 0000000..f9f27a5
--- /dev/null
+++ b/src/boot.stage2.gdt32.asm
@@ -0,0 +1,29 @@
+y    ;; boot.stage2.gdt32.asm
+
+    
+GDT32:  
+    .null:
+    dd 0x0
+    dd 0x0
+    .code:
+    dw 0xffff
+    dw 0x0000
+    db 0x00
+    db 10011010b
+    db 11001111b
+    db 0x00
+    .data:
+    dw 0xffff
+    dw 0x0000
+    db 0x00
+    db 10010010b
+    db 11001111b
+    db 0x00
+GDT32_end:  
+
+GDT32_ptr:  
+    .limit: dw GDT32_end - GDT32 - 1
+    .base: dd GDT32
+
+    CODE_SEG32 equ gdt32_code_segment - gdt32_start
+    DATA_SEG32 equ gdt32_data_segment - gdt32_start
-- 
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