因为前9个向量对xgate而言是空的。请参见xgate.cxgate源文件中的向量表及注释： const XGATE_TableEntry XGATE_VectorTable[] = {
// Channel # = Vector address / 2
/* channel 0..8 are not used, first used must match macro XGATE_VECTOR_OFFSET in xgate.h */
{ErrorHandler, 0x09}, // Channel 09 - Reserved
{ErrorHandler, 0x0A}, // Channel 0A - Reserved .... ... | 
