程序代码：

public _alloca_probe
_chkstk proc
_alloca_probe = _chkstk
    push  ecx
; Calculate new TOS.
    lea  ecx,[esp]+8-4
    sub  ecx,eax

;Handle allocation size that results in wraparound
;Wraparound will result in StackOverflow exception

    sbb  eax,eax
    not  eax
    and  ecx,eax

    mov  eax,esp
    and  eax,not

cs10:
    cmp  ecx,eax
    jb   short cs20
    mov  eax,ecx
    pop  ecx
    xchg esp,eax
    mov eax,dword ptr [eax]
    mov  dword ptr [esp],eax
    ret

;Find next lower page and probe
cs20:
    sub  eax,_PAGESIZE_
    test dword ptr [eax],eax
    jmp  short cs10

_Chkstk endp

    end