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Adding stack over/underflow check.

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This commit is contained in:
Brad Nelson
2022-07-31 21:53:13 -07:00
parent a32fce7334
commit 243087aee1
2 changed files with 7 additions and 2 deletions
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7
common/io.fs
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@ -93,9 +93,14 @@ create input-buffer input-limit allot
: tib-setup input-buffer 'tib ! ;
: refill tib-setup tib input-limit accept #tib ! 0 >in ! -1 ;
( Stack Guards )
sp0 'stack-cells @ 2 3 */ cells + constant sp-limit
: ?stack sp@ sp0 < if ." STACK UNDERFLOW " -1 throw then
sp-limit sp@ < if ." STACK OVERFLOW " -1 throw then ;
( REPL )
: prompt ." ok" cr ;
: evaluate-buffer begin >in @ #tib @ < while evaluate1 repeat ;
: evaluate-buffer begin >in @ #tib @ < while evaluate1 ?stack repeat ;
: evaluate ( a n -- ) 'tib @ >r #tib @ >r >in @ >r
#tib ! 'tib ! 0 >in ! evaluate-buffer
r> >in ! r> #tib ! r> 'tib ! ;