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UNRESOLVED EXTERNAL WITH FAR MEMORY TYPE

Applies to: C51 C Compiler

Answer


Information in this article applies to:


QUESTION

I am using the far memory type. Everything compiles fine, but during linkage I get the following error messages:

*** ERROR L127: UNRESOLVED EXTERNAL SYMBOL
    SYMBOL:  ?C?CLDXPTR
    MODULE:  C:KEILC51LIBC51BL.LIB (?C?CLDPTR)

*** ERROR L128: REFERENCE MADE TO UNRESOLVED EXTERNAL
    SYMBOL:  ?C?CLDXPTR
    MODULE:  C:KEILC51LIBC51BL.LIB (?C?CLDPTR)

What is the reason for these error messages?

ANSWER

You need to configure the bank switching module for the far memory type. Once this is done, the following memory access functions are available for accessing far memory:

?C?CLDXPTR, ?C?CSTXPTR  ; load/store BYTE (char)  in extended memory
?C?ILDXPTR, ?C?ISTXPTR  ; load/store WORD (int)   in extended memory
?C?PLDXPTR, ?C?PSTXPTR  ; load/store 3-BYTE PTR   in extended memory
?C?LLDXPTR, ?C?LSTXPTR  ; load/store DWORD (long) in extended memory

There are two modules that contain the template code for these functions. Both modules are found in source code in the folder KeilC51LIB.

Detailed configuration examples for various hardware platforms can be found in the folder KeilC51EXAMPLESFarMemory.

MORE INFORMATION

SEE ALSO

Article last edited on: 2005-02-14 18:20:22

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