C51S and movx/xdata

Since Keil (as opposed to some other compilers) do not supply the library in source, I have a question:
I am tasked with debugging some glitches in a very strange design: External memory is used and ALE is disabled. To access external RAM one must latch the low address in an external latch by toggling a p1 pin before executing external RAM access (movx). My question thus is: do the routines in C51S EVER execute movx.
I have no possibility of replacing thousands of hardware units, and already have the next version concept so I need the above question answered.

Thanks in advance

Erik

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  • The ALE is actually not connected in this @#$%^& design. I have disassembled the code and found a few cases using CLODPTR, an undocumented "shortcut subroutine" which actually uses MOVX. I am not criticising the compiler, who in his right mind would design a compiler anticipating such a design, I am only looking for help in the hunt for the unknown MOVX'es.

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  • The ALE is actually not connected in this @#$%^& design. I have disassembled the code and found a few cases using CLODPTR, an undocumented "shortcut subroutine" which actually uses MOVX. I am not criticising the compiler, who in his right mind would design a compiler anticipating such a design, I am only looking for help in the hunt for the unknown MOVX'es.

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