OpenEuphoria

Re: Need help with PD source (again)

• Posted by Vincent <darkvincentdude at yahoo.com> Apr 05, 2005
• 409 views

Matt Lewis wrote:
> 
> Pete Lomax wrote:
> > 
> > >
> > Matt Lewis wrote:
> > > So it's those ENDFOR_INT_UP1's and ENDFOR_GENERAL's that you need to 
> > > reproduce.
> >
> > You would need additional goto's after them, to properly exit the
> > loop, should you be on the last iteration. I think you would be better
> > off jumping to the existing endfor/endwhile statement instead.
> > Branch straightening might tidy things up automatically, with luck.
> 
> That seems wasteful (execution-wise) and requires changing the back end,
> anyway.  It was actually pretty simple to do.  I basically had to create
> a couple of stacks to remember the loop type, variable and the backpatch
> addresses, and added a continue statement.  In the for-loop case, I just
> added an exit right after the ENDFOR statement (ENDWHILE just jumps back
> to the while statement for evaluation).  Here's what the new routine looks 
> like:
> }}}
<eucode>
> procedure Continue_statement()
> 	token tok
> 	integer bp1, bp2
> 	sequence s
> 	if preprocess then
> 	    CompileErr("continue not allowed in preprocessing")
> 	end if
> 		
> 	if not loop_stack[$] then
> 	    CompileErr( "continue must be inside of loop" )
> 
> 	elsif loop_stack[$] = FOR then
> 	    StartSourceLine(TRUE)
> 	    op_info1 = loop_sym_stack[$]
> 	    op_info2 = loop_bp_stack[$] + 1
> 		s = Pop() & Pop()
> 		Push( s[2] )
> 		Push( s[1] )
> 	    emit_op(ENDFOR_GENERAL) -- will be set at runtime by FOR op
> 		Push( s[2] )
> 		Push( s[1] )
> 	    emit_op(EXIT)
> 	    AppendXList(length(Code)+1)
> 	    emit_forward_addr()     -- to be back-patched 
> 	    tok = next_token()
> 	    putback(tok)
> 	    
> 	elsif loop_stack[$] = WHILE then
> 		bp1 = loop_bp_stack[$][1]
> 		bp2 = loop_bp_stack[$][1]
> 	    StartSourceLine(TRUE)
> 	    emit_op(ENDWHILE)
> 	    emit_addr(bp1)
> 	    	
> 	end if
> 
> end procedure
> </eucode>
{{{

>  
> > How about duplicating AppendXList/PatchXList in parser.e?
> 
> I don't know what you mean by this...
> 
> Matt Lewis
> 

Awasome Matt & Pete, thanks so much for responding ...

I've implemented the "continue" keyword in emit.e, keylist.e,
opnames.e, and reswords.e. Matt, I implemented your
Continue_statement() in parser.e.

In parser.e I made stacks variables to hold the values in
For_statement() and While_statement().. like this
(tell me if Im wrong)..


... While_statement() *parser.e*

loop stack
----------
    loop_nest += 1
    loop_stack &= WHILE  <<--- (should this be T_ID instead?)


loop backpatch stack
--------------------
(bp1)
    bp1 = length(Code)+1
    loop_bp_stack &= bp1  <<--- here

(bp2)
    if not optimized_while then
	-- WHILE was emitted or combined into IFW op 

	bp2 = length(Code)+1
	loop_bp_stack &= bp2  <<--- here

	emit_forward_addr() -- will be patched 
    else -- WHILE TRUE was optimized to nothing 

	bp2 = 0
	loop_bp_stack &= bp2  <<--- here

    end if


... For_statement() *parser.e*

loop stack
----------
    loop_nest += 1
    loop_stack &= FOR  <<--- here


loop variable symbol stack
--------------------------
    loop_var_sym = loop_var[T_SYM]
    loop_sym_stack &= loop_var_sym  <<--- here


loop backpatch stack
--------------------
    bp1 = length(Code)+1
    loop_bp_stack &= bp1  <<--- here


Matt... I noticed in Continue_statement(), you put

s = Pop() & Pop()

and I'm not sure whats in it.. could you post the Pop() code
and tell where I could place the routine?

I got this error...
------------------------------------

C:\DOCUME~1\Vincent\Desktop\OFFICI~1\parser.e:923
Pop has not been declared
		s = Pop() & Pop()
		      ^
------------------------------------


I'm not sure what I should add in execute.e (backend) to
opFOR(), opFOR_GENERAL(), opENDFOR_INT_UP1(), opWHILE(),
etc..

Also I tracked "exit" (perhaps associated feature) here in
InitBackEnd() in execute.e...

    elsif find(name, {"EXIT", "ENDWHILE"}) then
        name = "ELSE"

I think opELSE is associated with that..

===============================================
Please Reply Matt and/or Pete :)


Thanks,
Vincent


Euphoria/VEEU v2.5 Rocks!!!