F850 UART bootloader 
It contains several parts.
* Bootloader firmware 
* PC software application
* Sample user application code
About bootloader real size, we need to check .M51 file 
instead of checking project build result output. The 
reason is there some GAPS interval among vector table. 
Here is the example:
When build project, IDE tells code size is 1023Bytes
Program Size: data=59.0 xdata=512 code=1023
LINK/LOCATE RUN COMPLETE.  0 WARNING(S),  0 ERROR(S)

But check the M51 file, the last function of bootloader locates 
at the last page. This means 0~0x400 are all occupied by bootloader,
So total size of bootloader is:
0x400+size_on_las_page = 0x400 + (0x1E43 - 0x1E00 + 0x13) = 1110 bytes.

            * * * * * * *   C O D E   M E M O R Y   * * * * * * *
            CODE    0000H     0002H     ABSOLUTE     
                    0002H     0001H                  *** GAP ***
            CODE    0003H     0002H     ABSOLUTE     
            CODE    0005H     0004H     UNIT         ?PR?OSCILLATOR_INIT?F85X_TARGETBL_DEVSPECIFIC
                    0009H     0002H                  *** GAP ***
            CODE    000BH     0002H     ABSOLUTE     
                    000DH     0006H                  *** GAP ***
            CODE    0013H     0002H     ABSOLUTE     
                    0015H     0006H                  *** GAP ***
            CODE    001BH     0002H     ABSOLUTE     
                    001DH     0006H                  *** GAP ***
            CODE    0023H     0002H     ABSOLUTE     
                    0025H     0006H                  *** GAP ***
            CODE    002BH     0002H     ABSOLUTE     
BL51 BANKED LINKER/LOCATER V6.22                                                                  10/15/2014  15:20:02  PAGE 2


                    002DH     0006H                  *** GAP ***
            CODE    0033H     0002H     ABSOLUTE     
                    0035H     0006H                  *** GAP ***
            CODE    003BH     0002H     ABSOLUTE     
                    003DH     0006H                  *** GAP ***
            CODE    0043H     0002H     ABSOLUTE     
                    0045H     0006H                  *** GAP ***
            CODE    004BH     0002H     ABSOLUTE     
                    004DH     0006H                  *** GAP ***
            CODE    0053H     0002H     ABSOLUTE     
                    0055H     0006H                  *** GAP ***
            CODE    005BH     0002H     ABSOLUTE     
                    005DH     0006H                  *** GAP ***
            CODE    0063H     0002H     ABSOLUTE     
                    0065H     0006H                  *** GAP ***
            CODE    006BH     0002H     ABSOLUTE     
                    006DH     0006H                  *** GAP ***
            CODE    0073H     0002H     ABSOLUTE     
            CODE    0075H     00E3H     UNIT         ?PR?MAIN?FXXX_TARGETBL_MAIN
            CODE    0158H     0085H     UNIT         ?C_C51STARTUP
            CODE    01DDH     0041H     UNIT         ?PR?_TGT_WRITE_FLASH?FXXX_TARGETBL_COMMANDS
            CODE    021EH     003BH     UNIT         ?C?LIB_CODE
            CODE    0259H     0037H     UNIT         ?PR?_GET_BUF_CRC?F85X_CRC
            CODE    0290H     002DH     UNIT         ?PR?_SRC_GET_PAGE?F85X_COMM_UART
            CODE    02BDH     0028H     UNIT         ?PR?_FLASH_MODIFY?F85X_FLASH
            CODE    02E5H     0024H     UNIT         ?PR?_UPDATE_CRC?F85X_CRC
            CODE    0309H     0023H     UNIT         ?PR?_UART_RECEIVE?F85X_COMM_UART
            CODE    032CH     001EH     UNIT         ?PR?SRC_GET_PAGE_INFO?F85X_COMM_UART
            CODE    034AH     001CH     UNIT         ?PR?_UART_SEND?F85X_COMM_UART
            CODE    0366H     001BH     UNIT         ?PR?_SRC_VALIDATE_PAGECRC?FXXX_TARGETBL_MAIN
            CODE    0381H     001BH     UNIT         ?PR?SRC_DISP_TGT_INFO?F85X_COMM_UART
            CODE    039CH     001BH     UNIT         ?PR?_SRC_DISP_INFO_CODE?F85X_COMM_UART
            CODE    03B7H     0019H     UNIT         ?PR?SRC_GET_INFO?F85X_COMM_UART
            CODE    03D0H     0018H     UNIT         ?PR?UART0_INIT?F85X_TARGETBL_DEVSPECIFIC
            CODE    03E8H     0012H     UNIT         ?PR?F85X_COMM_UART
                    03FAH     1A06H                  *** GAP ***
            CODE    1E00H     0010H     UNIT         ?PR?PORT_INIT?F85X_TARGETBL_DEVSPECIFIC
            CODE    1E10H     000EH     UNIT         ?PR?_SRC_VALIDATE_RESPONSE?FXXX_TARGETBL_MAIN
            CODE    1E1EH     000CH     UNIT         ?PR?DEVICE_INIT?F85X_TARGETBL_DEVSPECIFIC
            CODE    1E2AH     000AH     UNIT         ?C_INITSEG
            CODE    1E34H     0008H     UNIT         ?PR?_TGT_ERASE_PAGE?FXXX_TARGETBL_COMMANDS
            CODE    1E3CH     0007H     UNIT         ?PR?DISABLE_WATCHDOG?F85X_TARGETBL_DEVSPECIFIC
                    1E43H     00A8H                  *** GAP ***
            CODE    1EEBH     0013H     UNIT         ?CO?FXXX_TARGETBL_INFOBLOCK




