todo-i386

F:worksip2440a board可启动u-boot-like.tar.gz F:worksip2440a board可启动u-boot-like.tar.gz

i386 port missing features:
* i386 cleaness (wbinvld is 486+ ... )
* Pentium TSC timer/udelay
* setup the BIOS data area and BIOS equipment word to reflect machine config. 
* Make reset work (from Linux and from the boot prompt)
* DMA, FDC, RTC, KBC initialization
* split of part of cpu/i386/interrupt.c to cpu/i385/entry.c?
* re-entry of protected mode from real mode, should be added to realmode_switch.S 
  (and used by INT 10h and INT 16h handlers for console I/O during early
   linux boot...) 
* missing functions in lib_i386 and cpu/i386
* speaker beep interface


SC520 missing features:
* Watchdog
* SC520 timer/udelay
* SC520 3rd PIC
* SC520 ICE serial
* SC520 MMCR reset 

SC520 CDP board support missing features:
* environment in sram

SC520 CDP board support bugs:
* SPI EEPROM support does not work
* 0x680 LEDS dos not work for me
* is it possible to make both the internal serial ports and the 
  ports on the sio work at the same time?