[FORTH] proper way to iterate with offset?

[tschak909]

@cas and anyone else who can answer:

 

I currently have a routine that needs to iterate from a known address for a certain # of bytes, and it uses a VARIABLE to keep track of the start of the buffer.

 

What is the correct way to implement this, as this probably is completely wrong:

 

SCR # 78 
  0 ( FLD - DISPLAY FILENAME FOR SLOT )
  1 
  2 ( uses CURRENT variable )
  3 
  4 : .FLD"      ( n -- )
  5     CURRENT C!
  6     38 2 DO
  7         CURRENT C@ FLDBUF
  8         I +
  9         C@
 10         HEMIT
 11     LOOP ;
 12 
 13 
 14 
 15 -->

is the right thing to do to use the return stack? I genuinely am not comfortable with doing that, for some reason.

 

-Thom

[GarthW]

Does CURRENT get modified during the loop, by FLDBUF?  If not, you could forgo the use of the variable and just DUP it where it's needed in the loop, then get it off the data stack with DROP after LOOP.  Actually, to go further, if the DUP FLDBUF is going to always give you the same thing for any given time that .FLD" is called, why not do that just once, before you enter the loop, and put its result on the data stack, then do your DUP  I  +  C@  HEMIT  LOOP  DROP  ;  To further streamline things, if you use I + often enough, it's worth making it a primitive I+, and it might even be worth integrating more than that, like I+@.  Does the " at the end of the .FLD" name mean a string literal is supposed to follow in the source code?  Maybe there's too much here I'm not familiar with.