In article ,   
     wrote:   
   >In article <2024Mar5.125837@mips.complang.tuwien.ac.at>,   
   >Anton Ertl  wrote:   
   >>albert@spenarnc.xs4all.nl writes:   
   >>>In article <2024Mar4.182409@mips.complang.tuwien.ac.at>   
   >>>>My question is: Which Forth systems have a DO/?DO that pushes the   
   >>>>address [at run-time to the return stack] that LOOP/+LOOP then jumps to?   
   >>>   
   >>>All the versions of ciforth MS/Linux/OSX 32/64 ARM/86 do this.   
   >>   
   >>Thanks.  AFAIK you started with fig-Forth that puts the loop-back   
   >>address in the interpreted code.  Why did you change this approach?   
   >   
   >The address that I push is the address after the loop.   
   >So LEAVE as well as LOOP discards only loop parameters and go NEXT.   
   >(DO) is followed by a (FORWARD half jump, it doesn't jump over the   
   >body but is resolved by a FORWARD) , so it knows what   
   >address to push.   
   >If I remember correctly the original FIG LEAVE was not ISO, so this   
   >had to be fixed anyway. LEAVE and UNLOOP are almost synonyms.   
   >Simple manipulation of the return stack are preferred in view of my   
   >optimiser that can push return stack items into oblivion (registers).   
   >   
   >DO LOOP in FIG / ISO say FORTH is a mess anyway. The idea that   
   >signed/unsigned numbers can be handled uniformly was cute at the   
   >time, when you could not spare 10 bytes. In the 50 years no novice   
   >even dared to try negative indices or negative increments.   
   >   
   >>- anton   
   >Groetjes Albert   
      
   I looked at your original post again. Actually this is different.   
   +LOOP does a branch back. The address pushed on the return stack   
   is the address past the loop.   
      
   Groetjes Albert   
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