SHARE
TWEET

code for testing A20

a guest Feb 8th, 2019 14 Never
Not a member of Pastebin yet? Sign Up, it unlocks many cool features!
  1. %macro change_es 1
  2.     push ax
  3.     mov ax, %1
  4.     mov es, ax
  5.     pop ax
  6. %endmacro  
  7.  
  8.  
  9. TestA20:
  10.     push es
  11.  
  12.     change_es 0
  13.     mov ax, word [es:0x7DFE]
  14.     change_es 0xFFFF
  15.     mov bx, word [es:0x7E0E]
  16.     cmp ax, bx
  17.     jne .not_enabled
  18.  
  19.     change_es 0
  20.     ror byte [es:0x7DFE], 8
  21.     mov ax, word [es:0x7DFE]
  22.     change_es 0xFFFF
  23.     mov bx, word [es:0x7E0E]
  24.  
  25.     ; restore boot signature
  26.     change_es 0
  27.     rol word [es:0x7DFE], 8
  28.  
  29.     cmp ax, bx
  30.     jne .not_enabled
  31.  
  32.     .enabled:
  33.     mov ax, 0
  34.     jmp .done
  35.  
  36.  
  37.     .not_enabled:
  38.     mov ax, 1    
  39.  
  40.     .done:
  41.     pop es
  42.     ret
RAW Paste Data
We use cookies for various purposes including analytics. By continuing to use Pastebin, you agree to our use of cookies as described in the Cookies Policy. OK, I Understand
 
Top