mov     ecx,[month]
    mov     edx,[year]
    cmp     ecx,3
    sbb     edx,0
    mov     ecx,[.monthdata+ecx*4-4]
    mov     eax,edx
    imul    edx,0A3D8h
    shr     edx,22
    add     ecx,[day]
    add     ecx,eax
    shr     eax,2
    add     eax,ecx
    sub     eax,edx
    shr     edx,2
    add     eax,edx
    mov     ecx,eax
    mov     edx,24924925h
    mul     edx
    mov     eax,ecx
    lea     ecx,[edx+edx*2]
    lea     edx,[ecx+edx*4]
    sub     eax,edx

    .monthdata dd 0,3,2,5,0,3,5,1,4,6,2,4