How do you find the hub address of initialized data?

Comments

• potatohead Posts: 10,254

  2013-04-14 14:26 edited 2013-04-14 14:26

  Do you mean the @operator?
  
  What I do is look at the object listing in Pnut, then add the load address to it, which is usually $e80, but can be $1000, or something else
  

  TYPE: 4B   VALUE: 013402B8   NAME: XMIN
  TYPE: 4B   VALUE: 013802BC   NAME: YMIN
  TYPE: 4B   VALUE: 013C02C0   NAME: XMAX
  TYPE: 4B   VALUE: 014002C4   NAME: YMAX
  TYPE: 4B   VALUE: 014402C8   NAME: MAX_COMPUTE
  TYPE: 4B   VALUE: 014802CC   NAME: COLOR_MUL
  

  
  That is from the object listing for the fractal thing I just did. The VALUE: field is two words. For YMAX, these are 0140 02C4. The lower word is the HUB address, starting from 0. The upper word is the address relative to the ORG last issued.
  
  So then, YMAX lives at $0e80+$02c4 absolute HUB address.
  
  The "@" operator generally just needs the load address added to it for things to work nicely, if you've not padded the code with an array.
  
  IMHO, the monitor being in low RAM warrants and ORG and OBJ operator... or some other thing that specifies an address offset to work with.
  
  There is a more detailed explanation aimed at using the monitor to modify values, start COGS, etc... You can find that document here: http://forums.parallax.com/attachment.php?attachmentid=98587&d=1357887830
  
• Cluso99 Posts: 18,069

  2013-04-14 19:27 edited 2013-04-14 19:27

  pedward: If you fill the $e80 are with 0's and start your cog code at $e80, or fill to $1000 and start your cog code there, and use p2load to load it with the -s and optonally -h modifiers, you can do a straight @label. I do this throughout my P2 debugger so take a look there.
• pedward Posts: 1,642

  2013-04-14 20:23 edited 2013-04-14 20:23

  Well, I did get it to work this way:
  

  		setptrb	buffer
  		mov	buf, #fox
  		shl	buf, #2
  		add	buf, cogbase
  		call	#print_string
  
  print_string
  
  		setptra	buf
  :loop		rdbytec	c, PTRA++	wz
  if_nz		or	c, color
  if_nz		wrword	c, PTRB++
  if_nz		jmp	#:loop		
  		
  print_string_ret	ret
  
  
  cogbase		long	$E80
  fox		byte	"The quick brown fox jumped over the lazy dog.",0
  
  
• Cluso99 Posts: 18,069

  2013-04-14 22:11 edited 2013-04-14 22:11

  If you compile like this...

  CON
    _ROM_SIZE     = $E80                          ' length of ROM (i.e. the start of Hub Ram)
    _RESERVED     = $180                          ' reserved for drivers $00E80-$00FFF
    _COG_BASE     = _ROM_SIZE+_RESERVED           ' cog code entry
  
    _clkmode = xinput
    _xinfreq = 60_000_000
  ''============================[ DAT ]============================================================
  DAT
                  byte    0[_ROM_SIZE]            ' filler for ROM space $e80
                  byte    0[_RESERVED]            ' filler for reserved HUB space $180
  '$01000
                  
                  org     0
  entry
                  setptrb buffer
                  mov     buf, ptrfox
                  call    #print_string
  print_string
                  setptra buf
  :loop           rdbytec c, PTRA++       wz
          if_nz   or      c, color
          if_nz   wrword  c, PTRB++
          if_nz   jmp     #:loop          
                  
  print_string_ret
                  ret
  
  fox             byte    "The quick brown fox jumped over the lazy dog.",0 .
  ptrfox          long     @fox                   ' the hub address of string1
   
  

  
  and use p2load like this...
  

  p2load -v -s xxxx.obj -h -T
  

  
  p2load (-s) skips the first $e80 longs, and starts cog execution at (-h) $1000 hub.
  
  This method saves worrying about the $e80 offset.
  
  If you remove the -h, then execution will start at $e80, so delete the line allocating the
  byte 0[_RESERVED]