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pierre239955_stm1_stmicro_com
Visitor II
October 31, 2007
Question

St10 User stack

  • October 31, 2007
  • 2 replies
  • 732 views
Posted on October 31, 2007 at 09:48

St10 User stack

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    2 replies

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    pierre239955_stm1_stmicro_comAuthor
    Visitor II
    October 31, 2007
    Posted on October 31, 2007 at 05:44

    Hi all,

    I have a question about ST10 user stack.

    In my linker file, I located it at 0xF0100, size 0x2000; so from 0xF0100 to 0xF20FF

    In my startup file, I can see the user stack init :

    MOV R0,#DPP2:?C_USERSTKTOP

    ... but since R0 is a 16 bit register, the value may be truncated... When I run the simulator, after this MOV instruction, the updated R0 value is 0xA100... My target works fine but I can't understand this 0xA100 value.

    Could you explain me ?

    Thanks a lot !

    Pierre

    PS : I am using a ST10F276

    [ This message was edited by: pierre.roth on 31-10-2007 10:20 ]

    P
    pierre239955_stm1_stmicro_comAuthor
    Visitor II
    October 31, 2007
    Posted on October 31, 2007 at 09:48

    OK I found an explanation about DPP registers.

    User stack is located in NEAR memory which is accessed using DDP2.

    Therefore I think my R0 value is understandable :

    Stack located from 0xF0100 to 0xF20FF.

    R0 Value :

    Hex : A 1 0 0

    Bin : 1010 0001 0000 0000

    so DPP is 10 (bit 15-14) which is DDP2.

    DPP2 contains 0x3C and 0x3C * 4 = 0xF0 !!

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