kernel/kernel.asm

   1 ;-------------------------------------------------------;
   2 ;                      BOS kernel                       ;
   3 ;-------------------------------------------------------;
   4 ;    BOS 32-bit kernel, expects to be loaded at 32kb    ;
   5 ;    in mem.   Small amount of 16-bit code included.    ;
   6 ;                                                       ;
   7 ;      For any comments on this code, mail me.          ;
   8 ;   http://bos.asmhackers.net/   asmhacker@gmail.com    ;
   9 ;                                                       ;
  10 ;         by: Christoffer Bubach, 2003-2015             ;
  11 ;-------------------------------------------------------;
  12 use16
  13 org 0x8000
  14
  15 ;---------------------------;
  16 ;  jump to starting point   ;
  17 ;---------------------------;
  18         jmp    start
  19
  20 ;----------------------------------------;
  21 ;     16-bit include files               ;
  22 ;----------------------------------------;
  23     include  '16bit/a20.asm'                          ; Function to set the a20-gate.
  24     include  '16bit/gdt.asm'                          ; Global Description Table.
  25     include  '16bit/idt.asm'                          ; The Interrupt Description Table.
  26     include  '16bit/mem.asm'                          ; Get memory size.
  27     include  '16bit/variables.asm'                    ; For/from realmode.
  28     include  '16bit/init16bit.asm'                    ; Save "go back to 16-bit"-info.
  29
  30
  31
  32 ;--------------------------;
  33 ;   16-bit entry point     ;
  34 ;--------------------------;
  35 start:
  36         cli
  37         mov    ax, cs
  38         mov    ds, ax
  39                                                       ; fasm is more strict about
  40         xor    eax, eax                               ; "org 0x10000" then nasm, so
  41         mov    es, ax                                 ; i have to do -0x10000 from
  42         mov    fs, ax                                 ; all variable addresses while
  43         mov    gs, ax                                 ; in realmode.
  44         sti
  45
  46         call   enable_a20
  47         call   init16bit                              ; ...  :P
  48
  49         cli
  50         mov    ax, cs                                 ; save cs
  51         mov    [realmode_cs], ax                      ; in variables.inc
  52
  53         lgdt   [gdtr]                                 ; Load the GDT descriptor
  54         lidt   [idtr]                                 ; Load the IDT descriptor
  55
  56         mov    eax, cr0
  57         or     al, 1
  58         mov    cr0, eax
  59
  60         jmp    pword 0x08:flush                       ; dword in nasm
  61
  62
  63
  64 ;--------------------------;
  65 ;   32-bit entry point     ;
  66 ;--------------------------;
  67 use32
  68 flush:
  69         mov     ax, 0x10                              ; refresh all segment registers
  70         mov     ds, ax
  71         mov     es, ax
  72         mov     fs, ax
  73         mov     gs, ax
  74         mov     ss, ax
  75         mov     esp, 0xFFFC
  76
  77         call    bos_init                              ; fix everything
  78
  79         mov     bx, 0x04B1                            ; start the shell
  80         call    setcursor
  81         mov     esi, bos_shell
  82         mov     bl, 0x07
  83         call    print
  84         call    init_cmd
  85         jmp     shell
  86
  87         ;int     0x32
  88
  89     .hang:
  90         cli
  91         hlt
  92         jmp     .hang                                 ; hang, just in case..
  93
  94
  95 ;----------------------------------------;
  96 ;     32-bit include files               ;
  97 ;----------------------------------------;
  98     include  'int/idt.asm'                            ; The Interrupt Description Table.
  99     include  'vga/text.asm'                           ; The default textmode functions.
 100     include  'init/init32b.asm'                       ; Function that starts up BOS
 101     include  'vars/strings.asm'                       ; All strings in english (soon).
 102     include  'init/bios.asm'                          ; Get back to realmode and do an INT.
 103     include  'init/pic.asm'                           ; PIC rutines.
 104     include  'system/services.asm'                    ; System service handler (int 0x32).
 105     include  'kbd/keyboard.asm'                       ; Keyboard ISR.
 106     include  'kbd/keymap.asm'                         ; Keymap(s).
 107     include  'shell/shell.asm'                        ; File with shell/kernel monitor functions.
 108     include  'shell/commands.asm'                     ; Command table, for valid shell commands.
 109     include  'int/isr.asm'                            ; Interrupt Service Rutines.
 110     include  'int/debug.asm'                          ; Print contents of all regs and hang.
 111     include  'init/cmos.asm'                          ; To get CMOS data.
 112     include  'shell/clock.asm'                        ; Print time and date.
 113     include  'init/timer.asm'                         ; Timer IRQ.
 114     include  'vga/vga.asm'                            ; VGA functions.
 115 ;    include  'vga/font8x16.asm'                       ; Standard font.
 116     include  'fdc/dma.asm'                            ; DMA code.
 117     include  'fdc/fdc.asm'                            ; Floppy code.
 118     include  'vga/mario.asm'                          ; Mario sprite.
 119     include  'sound/speaker.asm'                      ; PC speaker.
 120     include  'ram/mem.asm'                            ; Memory allocation and freeing.
 121     include  'vfs/parse.asm'                          ; Path parser for VFS functions.