collapseos/apps/forth/core.fs

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: H HERE @ ;
: -^ SWAP - ;
: +! SWAP OVER @ + SWAP ! ;
: ALLOT HERE +! ;
: , H ! 2 ALLOT ;
: C, H C! 1 ALLOT ;
: BEGIN H ; IMMEDIATE
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: COMPILE ' ['] LITN EXECUTE ['] , , ; IMMEDIATE
: AGAIN COMPILE (bbr) H -^ C, ; IMMEDIATE
: NOT 1 SWAP SKIP? EXIT 0 * ;
: ( BEGIN LITS ) WORD SCMP NOT SKIP? AGAIN ; IMMEDIATE
( Hello, hello, krkrkrkr... do you hear me?
Ah, voice at last! Some lines above need comments
BTW: Forth lines limited to 64 cols because of default
input buffer size in Collapse OS
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COMPILE; Tough one. Get addr of caller word (example above
(bbr)) and then call LITN on it. However, LITN is an
immediate and has to be indirectly executed. Then, write
a reference to "," so that this word is written to HERE.
NOT: a bit convulted because we don't have IF yet )
: IF ( -- a | a: br cell addr )
COMPILE SKIP? ( if true, don't branch )
COMPILE (fbr)
H ( push a )
1 ALLOT ( br cell allot )
; IMMEDIATE
: THEN ( a -- | a: br cell addr )
DUP H -^ SWAP ( a-H a )
C!
; IMMEDIATE
: ELSE ( a1 -- a2 | a1: IF cell a2: ELSE cell )
COMPILE (fbr)
1 ALLOT
DUP H -^ SWAP ( a-H a )
C!
H 1 - ( push a. -1 for allot offset )
; IMMEDIATE
: ? @ . ;
: VARIABLE CREATE 2 ALLOT ;
: CONSTANT CREATE H ! DOES> @ ;
: = CMP NOT ;
: < CMP 0 1 - = ;
: > CMP 1 = ;
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: / /MOD SWAP DROP ;
: MOD /MOD DROP ;
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( Format numbers )
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( TODO FORGET this word )
: PUSHDGTS
999 SWAP ( stop indicator )
DUP 0 = IF '0' EXIT THEN ( 0 is a special case )
BEGIN
DUP 0 = IF DROP EXIT THEN
10 /MOD ( r q )
SWAP '0' + SWAP ( d q )
AGAIN
;
: . ( n -- )
( handle negative )
( that "0 1 -" thing is because we don't parse negative
number correctly yet. )
DUP 0 < IF '-' EMIT 0 1 - * THEN
PUSHDGTS
BEGIN
DUP '9' > IF DROP EXIT THEN ( stop indicator, we're done )
EMIT
AGAIN
;
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: PUSHDGTS
999 SWAP ( stop indicator )
DUP 0 = IF '0' EXIT THEN ( 0 is a special case )
BEGIN
DUP 0 = IF DROP EXIT THEN
16 /MOD ( r q )
SWAP ( r q )
DUP 9 > IF 10 - 'a' +
ELSE '0' + THEN ( q d )
SWAP ( d q )
AGAIN
;
: .X ( n -- )
( For hex display, there are no negatives )
PUSHDGTS
BEGIN
DUP 'f' > IF DROP EXIT THEN ( stop indicator, we're done )
EMIT
AGAIN
;