68013的固件中描述符定位的问题

采用slave fifo模式
我看cypress给的这种模式的固件程序中
在TD_Init()之后
有一部分代码是重定位描述符
不知道这部分代码是什么目的，为什么要重新定位描述符？请大侠指点
// The following section of code is used to relocate the descriptor table.
   // Since the SUDPTRH and SUDPTRL are assigned the address of the descriptor
   // table, the descriptor table must be located in on-part memory.
   // The 4K demo tools locate all code sections in external memory.
   // The descriptor table is relocated by the frameworks ONLY if it is found
   // to be located in external memory.
   pDeviceDscr = (WORD)&DeviceDscr;
   pDeviceQualDscr = (WORD)&DeviceQualDscr;
   pHighSpeedConfigDscr = (WORD)&HighSpeedConfigDscr;
   pFullSpeedConfigDscr = (WORD)&FullSpeedConfigDscr;
   pStringDscr = (WORD)&StringDscr;

   if (EZUSB_HIGHSPEED())
   {
      pConfigDscr = pHighSpeedConfigDscr;
      pOtherConfigDscr = pFullSpeedConfigDscr;
   }
   else
   {
      pConfigDscr = pFullSpeedConfigDscr;
      pOtherConfigDscr = pHighSpeedConfigDscr;
   }

   if ((WORD)&DeviceDscr & 0xe000)
   // If DeviceDscr is not in the 0x0000~0x1FFFF
   {
      IntDescrAddr = INTERNAL_DSCR_ADDR;
      ExtDescrAddr = (WORD)&DeviceDscr;
      DevDescrLen = (WORD)&UserDscr - (WORD)&DeviceDscr + 2;
      for (i = 0; i < DevDescrLen; i++)
         *((BYTE xdata *)IntDescrAddr+i) = 0xCD;
      for (i = 0; i < DevDescrLen; i++)
         *((BYTE xdata *)IntDescrAddr+i) = *((BYTE xdata *)ExtDescrAddr+i);
      pDeviceDscr = IntDescrAddr;
      offset = (WORD)&DeviceDscr - INTERNAL_DSCR_ADDR;
      pDeviceQualDscr -= offset;
      pConfigDscr -= offset;
      pOtherConfigDscr -= offset;
      pHighSpeedConfigDscr -= offset;
      pFullSpeedConfigDscr -= offset;
      pStringDscr -= offset;
   }

采用slave fifo模式
我看cypress给的这种模式的固件程序中
在TD_Init()之后
有一部分代码是重定位描述符
不知道这部分代码是什么目的，为什么要重新定位描述符？请大侠指点
// The following section of code is used to relocate the descriptor table.
   // Since the SUDPTRH and SUDPTRL are assigned the address of the descriptor
   // table, the descriptor table must be located in on-part memory.
   // The 4K demo tools locate all code sections in external memory.
   // The descriptor table is relocated by the frameworks ONLY if it is found
   // to be located in external memory.
   pDeviceDscr = (WORD)&DeviceDscr;
   pDeviceQualDscr = (WORD)&DeviceQualDscr;
   pHighSpeedConfigDscr = (WORD)&HighSpeedConfigDscr;
   pFullSpeedConfigDscr = (WORD)&FullSpeedConfigDscr;
   pStringDscr = (WORD)&StringDscr;

   if (EZUSB_HIGHSPEED())
   {
      pConfigDscr = pHighSpeedConfigDscr;
      pOtherConfigDscr = pFullSpeedConfigDscr;
   }
   else
   {
      pConfigDscr = pFullSpeedConfigDscr;
      pOtherConfigDscr = pHighSpeedConfigDscr;
   }

   if ((WORD)&DeviceDscr & 0xe000)
   // If DeviceDscr is not in the 0x0000~0x1FFFF
   {
      IntDescrAddr = INTERNAL_DSCR_ADDR;
      ExtDescrAddr = (WORD)&DeviceDscr;
      DevDescrLen = (WORD)&UserDscr - (WORD)&DeviceDscr + 2;
      for (i = 0; i < DevDescrLen; i++)
         *((BYTE xdata *)IntDescrAddr+i) = 0xCD;
      for (i = 0; i < DevDescrLen; i++)
         *((BYTE xdata *)IntDescrAddr+i) = *((BYTE xdata *)ExtDescrAddr+i);
      pDeviceDscr = IntDescrAddr;
      offset = (WORD)&DeviceDscr - INTERNAL_DSCR_ADDR;
      pDeviceQualDscr -= offset;
      pConfigDscr -= offset;
      pOtherConfigDscr -= offset;
      pHighSpeedConfigDscr -= offset;
      pFullSpeedConfigDscr -= offset;
      pStringDscr -= offset;
   }

这是哪个程序啊？我怎么从来没有看到过

如果FX2没有外部扩展的存储空间，也就是用的非128脚的芯片
那么这一部分代码是不是可以去掉了
因为程序代码只能放在on-chip的0x0000～0x1FFF范围内

首先描述符是放在代码段里面的，在操作之前必须使用数据指针从代码段中装载；
其次，如果描述符的地址如果大于0xffff时，就要特殊处理。否则可以去掉。