LorenOS

Os traigo el código fuente de LorenOS 1.0, el primer sistema operativo en ensamblador que hice (este no esta basado en MikeOS)

Disfrutadlo

;----------------------------------------------------------------------
;Sistema Operativo Kernel
;----------------------------------------------------------------------
org 0x7c00 ; This is where BIOS loads the bootloader

; Execution begins here
entry:
jmp short begin ; jump over the DOS boot record data

; ----------------------------------------------------------------------
; data portion of the "DOS BOOT RECORD"
; ----------------------------------------------------------------------
brINT13Flag DB 90H ; 0002h - 0EH for INT13 AH=42 READ
brOEM DB 'MSDOS5.0' ; 0003h - OEM name & DOS version (8 chars)
brBPS DW 512 ; 000Bh - Bytes/sector
brSPC DB 1 ; 000Dh - Sectors/cluster
brResCount DW 1 ; 000Eh - Reserved (boot) sectors
brFATs DB 2 ; 0010h - FAT copies
brRootEntries DW 0E0H ; 0011h - Root directory entries
brSectorCount DW 2880 ; 0013h - Sectors in volume, < 32MB
brMedia DB 240 ; 0015h - Media descriptor
brSPF DW 9 ; 0016h - Sectors per FAT
brSPH DW 18 ; 0018h - Sectors per track
brHPC DW 2 ; 001Ah - Number of Heads
brHidden DD 0 ; 001Ch - Hidden sectors
brSectors DD 0 ; 0020h - Total number of sectors
DB 0 ; 0024h - Physical drive no.
DB 0 ; 0025h - Reserved (FAT32)
DB 29H ; 0026h - Extended boot record sig
brSerialNum DD 404418EAH ; 0027h - Volume serial number (random)
brLabel DB 'Tu disco ' ; 002Bh - Volume label (11 chars)
brFSID DB 'FAT12 ' ; 0036h - File System ID (8 chars)
;------------------------------------------------------------------------

; --------------------------------------------
; Boot program code begins here
; --------------------------------------------
; boot code begins at 0x003E
begin:
xor ax, ax ; zero out ax
mov ds, ax ; set data segment to base of RAM
mov si, msg ; load address of our message
call putstr ; print the message

loop1:
xor ah, ah ; function 0
int 0x16 ; get a key from the keyboard

mov si, charmsg ; load address of message
call putstr ; print the message

mov ah, 0x0e ; function print character
mov bl, 0x07 ; white on black
int 0x10

mov si, newline ; print a newline
call putstr

jmp loop1 ; just loop forever.

; --------------------------------------------
; data for our program

msg db 'Bienvenido a EjemplOS, pulse una tecla...'
newline db 13,10,0
charmsg db 'Caracter tecleado: ',0

; ---------------------------------------------
; Print a null-terminated string on the screen
; ---------------------------------------------
putstr:
push ax
putstrl:
lodsb ; AL = [DS:SI]
or al, al ; Set zero flag if al=0
jz putstrd ; jump to putstrd if zero flag is set
mov ah, 0x0e ; video function 0Eh (print char)
mov bx, 0x0007 ; color
int 0x10
jmp putstrl
putstrd:
pop ax
retn
;---------------------------------------------

size equ $ - entry
%if size+2 > 512
%error "code is too large for boot sector"
%endif
times (512 - size - 2) db 0

db 0x55, 0xAA ;2 byte boot signature

Código de LorenOS 1.0

LorenOS 2.0

LorenOS 1.0