L166: ACCESSING THE USER STACK VIA DPP2
Information in this article applies to:
I have reassigned the DPP registers using the DPPUSE directive so that my memory is arranged as follows:
DPP VALUE C166 GROUP ======================== 0 0000H NCONST 1 0001H NDATA 2 0002H NDATA 3 0003H NDATA C166 GROUP START STOP ============================== NCONST 000000H 003FFFH NDATA 004000H 00FDFFH
When I examine the memory map of my module in the m66 file I see the following:
007D94H 007F93H 000200H DATA REL WORD --- 5 PUBL NDATA ?C_USERSTACK
The User Stack is now accessed by DPP1 rather than DPP2. Why is this, how do I tell the compiler that DPP1 accesses the User Stack and how do I force the linker to use DPP2 for User Stack accesses?
The linker is free to place the User Stack anywhere in the NDATA area. Because you have changed the boundries of the NDATA area by reassigning the DPP registers, NDATA can now be accessed by DPP1, DPP2 and DPP3. Therefore, the User Stack can be located so it may be accessed via DPP1, DPP2 or DPP3.
When you use the DPPUSE linker directive to reassign the DPP registers, you must also use the NOFIXDPP compiler directive. This ensures that the compiler no longer assumes the User Stack is accessed via DPP2.
You may use the SECTIONS linker directive to force the linker to place the User Stack in a section of memory accessed by DPP2. For example:
Last Reviewed: Friday, July 15, 2005
of your data.