Does the linker really generate these labels? (arm-elf-ld)

[Ken]

 

HI, respectable fighter:

    I'm now using Cygnus to build program on ARM architecture, but i meet a problem that the variable(s) will not be initialized by the system, so i take a look at the startup file provided by ATMEL, it used some external functions to do that thing, and remarked these labels are automatically generated by the linker, and i do so, but the linker tell me that it can't find such symbles:

 

cstartup_flash.o:cstartup_flash.s:339: undefined reference to `Image$$RO$$Limit'

cstartup_flash.o:cstartup_flash.s:339: undefined reference to `Image$$RW$$Base'
cstartup_flash.o:cstartup_flash.s:339: undefined reference to `Image$$ZI$$Base'
cstartup_flash.o:cstartup_flash.s:339: undefined reference to `Image$$ZI$$Limit'

 

Does the linker really generate these labels?

 

Here is the part of startup file:

 

;------------------------------------------------------------------------------
;- Initialise C variables
;------------------------
;- Following labels are automatically generated by the linker.
;- RO: Read- code
;- RW: Read Write = the data pre-initialized and zero-initialized.
;- ZI: Zero-Initialized.
;- Pre-initialization values are located after the code area in the image.
;- Zero-initialized datas are mapped after the pre-initialized.
;- Note on the Data position :
;- If using the ARMSDT, when no -rw-base option is used for the linker, the
;- data area is mapped after the code. You can map the data either in internal
;- SRAM ( -rw-base=0x40 or 0x34) or in external SRAM ( -rw-base=0x2000000 ).
;- Note also that to improve the code density, the pre_initialized data must
;- be limited to a minimum.
;------------------------------------------------------------------------------
                IMPORT      |Image$$RO$$Limit|      ; End of ROM code (=start of ROM data)
                IMPORT      |Image$$RW$$Base|       ; Base of RAM to initialise
                IMPORT      |Image$$ZI$$Base|       ; Base and limit of area
                IMPORT      |Image$$ZI$$Limit|      ; to zero initialise

 

                ldr         r0, =|Image$$RO$$Limit| ; Get pointer to ROM data
                ldr         r1, =|Image$$RW$$Base|  ; and RAM copy
                ldr         r3, =|Image$$ZI$$Base|  ; Zero init base => top of initialised data
                cmp         r0, r1                  ; Check that they are different
                beq         NoRW
LoopRw          cmp         r1, r3                  ; Copy init data
                ldrcc       r2, [r0], #4
                strcc       r2, [r1], #4
                bcc         LoopRw
NoRW            ldr         r1, =|Image$$ZI$$Limit| ; Top of zero init segment
                mov         r2, #0
LoopZI          cmp         r3, r1                  ; Zero init
                strcc       r2, [r3], #4
                bcc         LoopZI

    Best regards
--------------------------------------
    Justin Zhang
    R&D Dept
    Tel: 62385599-5809
    Fax: 62389059
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    Beijing Comsys Tech. Co., Ltd.