A51: ACCESSING PDATA VARIABLES IN ASSEMBLER
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In a C source file, I have declared a pdata variable called foo. I wish to access this variable in an assembly module, and I have written the following code to do this:
EXTRN XDATA (foo) ... MOV R0, #foo MOV @R0, A
However, when I build my project I get:
ERROR 121: IMPROPER FIXUP.
While using the EXTRN directive, you have specified the variable as xdata. This is correct since pdata variables are stored in xdata, however, the assembler assigns a 16-bit address to the variable, but only an 8-bit address exists for the pdata variable.
Move the lower byte of the 16-bit address of the variable into R0. The upper byte will be present on P2 during the memory access.
MOV R0, #LOW (foo)
Last Reviewed: Tuesday, June 8, 2004
of your data.