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How to define a lit23 GOTO in PCD?

 
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FvM



Joined: 27 Aug 2008
Posts: 2337
Location: Germany

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How to define a lit23 GOTO in PCD?
PostPosted: Thu Sep 25, 2008 8:03 am     Reply with quote
Hello,

in EX_PCD_Bootloader.c, a jump to the real bootloader is performed by
Code:
      #asm
      goto LOADER_ADDR
      #endasm


For most PIC24 chips, LOADER_ADDR is a 23-Bit literal, e. g. 0x207FA.
PCD inserts a far GOTO instruction, but strips of the upper bits. Even inserting 23 Bit constant instead of a symbol doesn't generate the correct address.

There is also a built-in function goto_address(), but it seems to generate a near branch instruction unconditionally.

How to perform the necessary far GOTO?

Regards,
Frank
FvM



Joined: 27 Aug 2008
Posts: 2337
Location: Germany

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PostPosted: Thu Sep 25, 2008 8:30 am     Reply with quote
As an additional question, how to use symbols in literal MOV instructions, e. g.:
Code:
#asm
MOV  #LOADER_ADDR, W0

It gives an error Invalid Pre-Processor directive. I don't see that PCD provides an option.
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