I got a problem here.. I have defined a pointer like this:

var    vaddr            : word;
       vaddrp           : pointer;

begin
  getmem(vaddrp,64000); vaddr:=seg(vaddrp^);

[cut]

type
  Tvidscreen = array[0..63999] of byte;
  Pvidscreen = ^Tvidscreen;

var
  vaddrp : Pvidscreen;

begin
  new (vaddrp);
  vaddrp^[32000] := 15;
  {...}
  dispose (vaddrp);
end;

I just want to make one extra point here.  From what I can tell, you're using this as a
buffer page for graphics, specifically mode 13h.  Now, you're assigning the segment of
vaddrp^ to vaddr.  IMHO, do not, do not, DO NOT do this.  When you define a block on the
heap, you can not assume that the offset it 0.  In TP7, it could be 0 or 8 (and I think
earlier versions may be 0 or 16).  So, just using the segment has a chance for pointing
in the vicinity of the memory block, not to the block itself.  This can cause unexpected
bugs.  If you're going to use a pointer, use the whole pointer.

If you're using BASM, you can use "les di,[ptrname]" to load a pointer, and in regular
TP, you can use pointer arithmetic.

    This problem is not a problem !!!

    You could simply define another pointer and then load address in it
    via function PTR(segment,Offset:Integer):Pointer

EXAMPLE: You want to access position 32000!

var
  vaddr:word;
  vaddrp:pointer;
  other_pointer:pointer;
begin
  getmem(vaddrp,64000);
  ......
  do anything
  .......
  other_pointer:=Ptr(vaddr,32000);

   ***
end.
[cut]

After that you can "other_pointer" will contain address to 32000'th item!

Hope, it will help ya!

In <3245A50D.5...@algonet.se>, Erik Lundh <may...@algonet.se> writes:

step 1.
    Define a TYPE that will contain your buffer.

    type
       big_byte_type = Packed array [0..63999] of byte;
       big_word_type = Packed array [0..31999] of word;

    var
       uPointer : ^big_byte_type;

    begin
    new(upointer);
    { to access it as an array of bytes }
    upointer^[1] := 0;
    { to access it as an array of words }
    big_word_type(upointer^)[2] := 3;
    end;

   You can use the MEM or MEMW command

   Example:    MyData := MemW[Seg(vaddrp):Ofs(vaddrp)];

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