amd64/bareMetalOS-0.5.2/pure64.boot0/bootsector/pxestart.asm

   1 ; =============================================================================
   2 ; Pure64 PXE Start -- a 64-bit OS loader written in Assembly for x86-64 systems
   3 ; Copyright (C) 2008-2011 Return Infinity -- see LICENSE.TXT
   4 ;
   5 ; This is a stub file for chainloading Pure64 and a Kernel via PXE.
   6 ;
   7 ; You will need to uncomment the Chainloading lines in pure64.asm
   8 ;
   9 ; Windows - copy /b pxestart.bin + pure64.sys + kernel64.sys pxeboot.bin
  10 ; Unix - cat pxestart.bin pure64.sys kernel64.sys > pxeboot.bin
  11 ;
  12 ; Max size of the resulting pxeboot.bin is 32768 bytes. PXE loads the file to
  13 ; address 0x00007C00 (Just like a boot sector).
  14 ;
  15 ; File Sizes
  16 ; pxestart.bin   1024 bytes
  17 ; pure64.sys     6144 bytes
  18 ; kernel64.sys  16384 bytes (or so)
  19 ; =============================================================================
  20
  21
  22 USE16
  23 org 0x7C00
  24
  25 start:
  26         xor eax, eax
  27         xor esi, esi
  28         xor edi, edi
  29         mov ds, ax
  30         mov es, ax
  31         mov bp, 0x7c00
  32
  33 ; Make sure the screen is set to 80x25 color text mode
  34         mov ax, 0x0003                  ; Set to normal (80x25 text) video mode
  35         int 0x10
  36
  37 ; Print message
  38         mov si, msg_Load
  39         call print_string_16
  40
  41         jmp 0x0000:0x8000
  42
  43 ;------------------------------------------------------------------------------
  44 ; 16-bit Function to print a sting to the screen
  45 ; input: SI - Address of start of string
  46 print_string_16:                        ; Output string in SI to screen
  47         pusha
  48         mov ah, 0x0E                    ; int 0x10 teletype function
  49 .repeat:
  50         lodsb                           ; Get char from string
  51         cmp al, 0
  52         je .done                        ; If char is zero, end of string
  53         int 0x10                        ; Otherwise, print it
  54         jmp short .repeat
  55 .done:
  56         popa
  57         ret
  58 ;------------------------------------------------------------------------------
  59
  60
  61 msg_Load db "Loading via PXE... ", 0
  62
  63 times 510-$+$$ db 0     ; Pad out for a normal boot sector
  64
  65 sign dw 0xAA55
  66
  67 times 1024-$+$$ db 0    ; Padding so that Pure64 will be aligned at 0x8000