[bits  32]
; Define  some  constants
VIDEO_MEMORY  equ 0xb8000
WHITE_ON_BLACK  equ 0x0f
; prints a null -terminated  string  pointed  to by EDX
print_string_pm:
  pusha
  mov edx, VIDEO_MEMORY  ; Set  edx to the  start  of vid  mem.
print_string_pm_loop:
  mov al, [ebx]          ; Store  the  char at EBX in AL
  mov ah, WHITE_ON_BLACK ; Store  the  attributes  in AH
  cmp al, 0         ; if (al == 0), at end of string , so
  je print_string_pm_done
  mov [edx], ax     ; Store  char  and  attributes  at  current
                    ; character  cell.
  add ebx , 1       ; Increment  EBX to the  next  char in  string.
  add edx , 2       ; Move to next  character  cell in vid  mem.
  jmp  print_string_pm_loop   ; loop  around  to  print  the  next  char.
print_string_pm_done:
  popa
  ret               ; Return  from  the  function