Issue 4 - propellerforth - Stack underflow breaks .S

Issue 4:	Stack underflow breaks .S	‹ Prev 4 of 7 Next ›
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Status:	New
Owner:	----
Type-Defect
Priority-Medium

Reported by jokurki, Jun 06, 2008

What steps will reproduce the problem?
1. DROP
2. DROP
3. .S

What is the expected output? What do you see instead?
.S should abort with Stack Underflow error, instead it begins dumping
entire 32-bit address space with no apparent way to stop (board reset works).

What version of the product are you using? On what operating system?
8.1

Please provide any additional information below.

My current fix
( Safer version of .S )
: S.S SP@ sp0 @ <
  if ." Stack underflow"
  else .s
  then
;

Comment 1 by jokurki, Jun 09, 2008

After a bit of study, it seems that PropellerForth Interpreter is culprit. Usually
the Forth Interpreter checks the parameter stack status after each Execute. I copied
this one from Starting Forth web edition. 

: INTERPRET ( -- )
		BEGIN
		   BL WORD FIND IF  EXECUTE ?STACK ABORT" Stack empty"
			      ELSE  NUMBER
			      THEN 
		AGAIN ;