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% DOL3 Core V003 in alpha                  %
% Author: Steven Messenger                 %
% Copyright (c) 2010 Steven Messenger      %
% See end of file for terms of use.        %
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This is DOL3 (Dynamic Object Launcher). A big improvement on the original DOL and DOL2, well it would be if I
tested it...

This version cuts back on everything so it will be more useful.

**************
*Known Issues*
**************
0001 - Found in versions: V001 beta
     - Description: Not finished yet!
     - Workaround: Wait for me to finish it!
     - Fixed in version:
     - Credit: Steven

0002 - Found in versions: V002
     - Description: Need to compile using Sphinx to get the object address constants and object referencing working.
     - Workaround: Wait for someone else to modify other spin compilers!
     - Fixed in version: V003 - No long an issue in DOL itself, now only a problem in objects you want to load.
     - Credit: Steven

**********
*Versions*
**********
V003 - Released: not yet
     - New features
       - Much simplified, DOL should now be used as a child rather than a parent.
       - It is now up to the parent application to deallocate memory.
     - Bug fixes
       - N/A
     - Other improvements
       - N/A
     - API changes
       - Removed everything except "loadObject" and that has been significantly changed. When you want to load an object
         simply call this with a pointer to a file name in "fileNamePtr" and a "0" in "mode" to load an entire object. If
         you put a current object address in "mode" than only space for the var part of the object will be allocated, just
         like happens when you compile a spin program on a p.c. The value returned is the object address that you would
         use as demonstrated in the objTemp.spn file.

}}
CON
  'abort values. If something goes wrong, aborted gets set to TRUE and one of these values is returned.
  #0
  AbortNotEnoughMemory      'There is not enough memory left to complete the operation
  AbortCouldNotFindFile     'The file could not be found
  
  FULL=0

OBJ
  sd    : "fsrwDOL"
  mem   : "heap"

VAR
  long aborted

PUB loadObject(fileNamePtr,mode)|objectLength,varSize,objectStartBase,objectAddr
  'open file
  if sd.popen(fileNamePtr,"r")<>0
    long[@aborted]:=true
    abort AbortCouldNotFindFile

  'read ProgramStart, VARStart and StackStart from header
  'subtracting these will give us program length and var length
  'set objectSize - from header
  'read all the data in the header and use whatever we need
  repeat 8
    sd.pgetc
  objectLength:=sd.pgetc '8  'byte of varBASE
  objectLength.byte[1]:=sd.pgetc '9  'byte of varBase
  objectLength:=objectLength-$10
  varSize:=sd.pgetc 'A  'byte of stack start
  varSize.byte[1]:=sd.pgetc 'B  'byte of stack start
  varSize:=VARSize-$10-objectLength-8 '-$8 fudge factor to be figured out
  repeat 4    'get to end of header
    sd.pgetc

  if mode==FULL
    'allocate space for methods
    objectStartBase:=mem.allocate(objectLength+3) 'need the extra 3 bytes so we can make sure that the object is long aligned
    if objectStartBase<10
      long[@aborted]:=true
      mem.free(objectStartBase)
      sd.pclose
      abort AbortNotEnoughMemory
    'long align the object space
    objectStartBase:=(objectStartBase+3)&!%11
    'load methods
    sd.pread(objectStartBase,objectLength)
  else
    objectStartBase:=mode.word[0]

  sd.pclose

  'allocate space for VAR
  objectVarBase:=mem.allocate(varSize+3) 'need the extra 3 to ensure vars are long aligned
  if objectVarBase<10
    long[@aborted]:=true
    mem.free(objectVarBase)
    if mode==FULL
      mem.free(objectStartBase)
    abort AbortNotEnoughMemory
  'long align the variables
  objectVarBase:=(objectVarBase+objectVarBase+3)&!%11
  'zero the var area
  bytefill(objectVarBase,0,varSize)

  objectAddr.word[0]:=objectStartBase
  objectAddr.word[1]:=objectVarBase

  return objectAddr

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%                                                   TERMS OF USE: MIT License                                                  %
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