xor     edx,edx
 mov     dr0,edx
 mov     dr1,edx
 mov     dr2,edx
 mov     dr3,edx

;; debug registers clearing example by dr.golova
;; mailto: dr_golova#pisem.net
;; fully multihreaded and position-independent code
;; compile it with netwide assembler
;; e.g. nasmw.exe -o drx_clr.bin -f bin -O4 drx_clr.asm

bits 32
section .text
global  _start

_start:
;;         int    3
         call   .pbase                           ;; push code address
.pbase:
         xor    eax, eax
         add    dword [esp], (.x_hnd - .pbase)   ;; update handler offset
         push   dword [fs:eax]                   ;; save old exception handler
         mov    dword [fs:eax], esp              ;; setup new handler frame
         mov    eax,  [eax]                      ;; exception here
         pop    dword [fs:eax]                   ;; restore old frame
         pop    eax
         retn
.x_hnd:
         xor    eax, eax
         mov    ecx,  [esp+00Ch]                 ;; context ptr
         mov    dword [ecx], 010017h             ;; set context flags
         add    dword [ecx+0B8h], 02h            ;; exception address
         mov    dword [ecx+018h], 0101h          ;; setup dr7 flags
         mov    [ecx+04h], eax                   ;; clear dr0-dr3
         mov    [ecx+08h], eax
         mov    [ecx+0Ch], eax
         mov    [ecx+10h], eax
         retn                                    ;; return to host
end