Initial commit

.gitignore

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+*.bin
+*.img

Makefile

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+disk.img: boot kernel
+	cat boot.bin kernel.bin > disk.img
+
+boot.bin: boot.asm
+	nasm boot.asm -o $@
+
+kernel.bin: kernel.asm
+	nasm kernel.asm -o $@

boot.asm

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+[BITS 16]  ;tell the assembler that its a 16 bit code
+
+mov ax, 7c0h
+mov ds, ax
+
+mov si, _boot_msg
+call _boot_print
+
+mov ah, 02h
+mov al, 1
+mov ch, 0
+mov cl, 2
+mov dh, 0
+
+mov bx, 2000h
+mov es, bx
+xor bx, bx
+int 13h
+
+jmp 2000h:0
+
+_boot_print:
+  mov ah, 0eh
+  mov cx, 1
+  mov bh, 0
+_boot_print_loop:
+  lodsb
+  cmp al, 0
+  je _boot_print_exit
+  int 10h
+  jmp _boot_print_loop
+_boot_print_exit:
+  ret
+
+_boot_msg db "Boot Sector OK!", 13, 10, 0
+
+TIMES 510 - ($ - $$) db 0    ;fill the rest of sector with 0
+DW 0xAA55          ; add boot signature at the end of bootloader

kernel.asm

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+sect2:
+  mov ax, 2000h
+  mov ds, ax
+
+  mov si, msg
+  call print
+
+  mov si, msg2
+  call print
+
+  jmp $
+
+  msg db "Kernel OK!", 13, 10, 0
+  msg2 db "Hello, World!", 13, 10, 0
+
+print:
+  mov ah, 0eh
+  mov cx, 1
+  mov bh, 0
+print_loop:
+  lodsb
+  cmp al, 0
+  je print_exit
+  int 10h
+  jmp print_loop
+print_exit:
+  ret
+