import struct, re
EXES = ['/Users/jing/Documents/yutong/yutongapp/TP5(En).exe',
        '/Users/jing/Documents/yutong/yutongapp/TP5(Cn).exe']

def crc_table16(poly, reflect):
    t=[]
    for i in range(256):
        if reflect:
            c=i
            for _ in range(8):
                c = (c>>1) ^ (poly if c&1 else 0)
        else:
            c=i<<8
            for _ in range(8):
                c = ((c<<1)^poly)&0xffff if c&0x8000 else (c<<1)&0xffff
        t.append(c&0xffff)
    return t

def crc_table32(poly, reflect):
    t=[]
    for i in range(256):
        if reflect:
            c=i
            for _ in range(8):
                c = (c>>1) ^ (poly if c&1 else 0)
        else:
            c=i<<24
            for _ in range(8):
                c = ((c<<1)^poly)&0xffffffff if c&0x80000000 else (c<<1)&0xffffffff
        t.append(c&0xffffffff)
    return t

polys16 = [0x1021,0x8408,0x8005,0xa001,0x3d65,0xa6bc,0xc867,0x0589,0x8bb7,0x8d95,0x1DCF,0x755B]
for path in EXES:
    d=open(path,'rb').read()
    print('===', path, len(d))
    for p in polys16:
        for refl in (0,1):
            t = crc_table16(p, refl)
            blob = b''.join(struct.pack('<H',x) for x in t[:16])
            i = d.find(blob)
            print('  tbl16 poly=%04x refl=%d -> %s' % (p,refl, hex(i) if i>=0 else '-'))
    # generic immediate search for 16-bit polys used in bitwise loop:
    # look for "xor ax, imm16" = 66 35 xx xx  or "xor eax, imm32" = 35 xx xx xx xx
    for m in re.finditer(rb'\x66\x35(..)', d, re.S):
        pass