Adding data to an "array" in ASM

[Bruce]

The first part of this probably isn't working like you might expect.

  movlw   _bOutDataPos    ; gets the "address" of bOutDataPos into W
  addwf   _bOutData,w     ; adds the address + the "value" in bOutData
  movwf   FSR             ; loads FSR with the wrong address

You want to add the base address of the array, which will never change, to the
offset value in bOutDataPos to get the address for each array element;

  movf   _bOutDataPos,W   ; get the value of your index pointer in bOutDataPos
  addlw  _bOutData        ; add the index to the base address of your array
  movwf  FSR              ; load FSR with base address + offset

This will probably make it easier to follow;

Array       VAR BYTE[8]
Index       VAR BYTE
Address     VAR BYTE

Action      CON 10
ControlChar CON 20

CLEAR

Address = 15  ' address
Index = 0     ' starting Array Index position

Main:
 Array[Index]=ControlChar
 Index=Index+1
 Array[Index]=0
 Index=Index+1
 Array[Index]=Address
 Index=Index+1
 Array[Index]=Action
 Index=Index+1
 GOTO Main

The code after Main would be something like this, which maintains your Index pointer.

asm
  movf   _Index, W     ;get "offset" value from Index pointer
  addlw  _Array        ;add it to Array[0] base address (result in W)           
  movwf  FSR           ;load pointer with base + offset  
  movlw  _ControlChar  ;load W with constant value in ControlChar
  movwf  INDF          ;move it to Array[Index]
  incf   _Index, F     ;inc Index pointer  
  movf   _Index, W     ;load new Index pointer value  
  addlw  _Array        ;add it to Array[0] base address            
  movwf  FSR           ;load pointer with base + offset  
  clrf   INDF          ;Clear Array[Index]  
  incf   _Index, F     ;inc Index pointer  
  movf   _Index, W     ;load new Index pointer value
  addlw  _Array        ;add it to Array[0] base address           
  movwf  FSR           ;load pointer with base + offset  
  movf   _Address, W   ;get Address byte value  
  movwf  INDF          ;move it to Array[Index]  
  incf   _Index, F     ;inc Index pointer  
  movf   _Index, W     ;load new Index pointer value  
  addlw  _Array        ;add it to Array[0] base address          
  movwf  FSR           ;load pointer with base + offset  
  movlw  _Action       ;load W with Constant value in Action
  movwf  INDF          ;move it to Array[Index]  
  incf   _Index, F     ;inc Index pointer
endasm

It could be made a bit smaller, and you could use incf FSR to increment the
pointer each time, but you could lose track of which array element you last
wrote to pretty quick.