Refractor: Moved each file to their respective folder.

2025-11-19 20:16:36 +00:00
parent 3bd026ca7a
commit 8f9ea8b71f
4 changed files with 1 additions and 1 deletions
@@ -0,0 +1,94 @@
+; File: boot.asm
+; Stage 1 Bootloader (Master Boot Record - exactly 512 bytes)
+; Job: Load Stage 2 from disk and jump to it
+
+[org 0x7c00]
+[bits 16]
+
+STAGE2_OFFSET equ 0x7e00    ; Load stage2 right after boot sector
+
+start:
+    ; Set up segments
+    xor ax, ax
+    mov ds, ax
+    mov es, ax
+    mov ss, ax
+    mov sp, 0x7c00
+    
+    ; IMPORTANT: Save boot drive number (BIOS passes it in DL)
+    push dx
+
+    ; Clear screen
+    mov ah, 0x00
+    mov al, 0x03
+    int 0x10
+
+    ; Print loading message
+    mov si, msg_loading
+    call print_string
+
+    ; Load Stage 2 from disk
+    ; Read 5 sectors (sectors 2-6) - gives us 2.5KB for Stage 2
+    pop dx                  ; Restore boot drive
+    push dx                 ; Save it again for stage 2
+    mov bx, STAGE2_OFFSET   ; Destination
+    mov dh, 5               ; Number of sectors
+    ; DL already has drive number
+    call load_disk
+
+    ; Jump to Stage 2 (DL still has boot drive number)
+    pop dx                  ; Pass drive number to stage 2 in DL
+    jmp STAGE2_OFFSET
+
+; ============================================================
+; LOAD DISK - Read sectors using BIOS INT 0x13
+; ============================================================
+load_disk:
+    push dx
+    
+    mov ah, 0x02        ; Read function
+    mov al, dh          ; Number of sectors
+    mov ch, 0           ; Cylinder 0
+    mov cl, 2           ; Start at sector 2
+    mov dh, 0           ; Head 0
+    
+    int 0x13
+    jc disk_error
+    
+    pop dx
+    cmp al, dh
+    jne disk_error
+    ret
+
+disk_error:
+    mov si, msg_error
+    call print_string
+    jmp $
+
+; ============================================================
+; PRINT STRING
+; ============================================================
+print_string:
+    pusha
+    mov ah, 0x0e
+.loop:
+    lodsb
+    test al, al
+    jz .done
+    int 0x10
+    jmp .loop
+.done:
+    popa
+    ret
+
+; ============================================================
+; DATA
+; ============================================================
+msg_loading: db '[STAGE1] Loading SoraOS...', 0x0D, 0x0A, 0
+msg_error:   db '[ERROR] Disk read failed!', 0x0D, 0x0A, 0
+
+; ============================================================
+; BOOT SIGNATURE
+; ============================================================
+times 510-($-$$) db 0
+dw 0xAA55