mirror of https://github.com/hsoft/collapseos.git
204 lines
4.7 KiB
Forth
204 lines
4.7 KiB
Forth
: H@ HERE @ ;
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: IMMEDIATE
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CURRENT @ 1-
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DUP C@ 128 OR SWAP C!
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;
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: [ INTERPRET ; IMMEDIATE
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: ] R> DROP ;
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: LITS 34 , SCPY ;
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: LIT< WORD LITS ; IMMEDIATE
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: LITA 36 , , ;
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: '
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WORD (find) (?br) [ 4 , ] EXIT
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LIT< (wnf) (find) DROP EXECUTE
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;
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: ['] ' LITA ; IMMEDIATE
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: COMPILE ' LITA ['] , , ; IMMEDIATE
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: [COMPILE] ' , ; IMMEDIATE
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: BEGIN H@ ; IMMEDIATE
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: AGAIN COMPILE (br) H@ - , ; IMMEDIATE
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: UNTIL COMPILE (?br) H@ - , ; IMMEDIATE
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: _ BEGIN LIT< ) WORD S= UNTIL ; IMMEDIATE
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40 CURRENT @ 4 - C!
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( Hello, hello, krkrkrkr... do you hear me?
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Ah, voice at last! Some lines above need comments
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BTW: Forth lines limited to 64 cols because of default
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input buffer size in Collapse OS
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"_": words starting with "_" are meant to be "private",
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that is, only used by their immediate surrondings.
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40 is ASCII for '('. We do this to simplify XPACK's task of
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not mistakenly consider '(' definition as a comment.
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LITS: 34 == litWord
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LITA: 36 == addrWord
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COMPILE: Tough one. Get addr of caller word (example above
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(br)) and then call LITA on it. )
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: +! SWAP OVER @ + SWAP ! ;
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: -^ SWAP - ;
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: ALLOT HERE +! ;
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: IF ( -- a | a: br cell addr )
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COMPILE (?br)
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H@ ( push a )
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2 ALLOT ( br cell allot )
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; IMMEDIATE
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: THEN ( a -- | a: br cell addr )
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DUP H@ -^ SWAP ( a-H a )
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!
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; IMMEDIATE
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: ELSE ( a1 -- a2 | a1: IF cell a2: ELSE cell )
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COMPILE (br)
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2 ALLOT
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DUP H@ -^ SWAP ( a-H a )
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!
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H@ 2- ( push a. -2 for allot offset )
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; IMMEDIATE
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( During a CASE, the stack grows by 1 at each ENDOF so that
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we can fill all those ENDOF branching addrs. So that we
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know when to stop, we put a 0 on PSP. That's our stopgap. )
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: CASE 0 COMPILE >R ; IMMEDIATE
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: OF
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COMPILE I COMPILE =
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[COMPILE] IF
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; IMMEDIATE
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: ENDOF [COMPILE] ELSE ; IMMEDIATE
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( At this point, we have something like "0 e1 e2 e3 val". We
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want top drop val, and then call THEN as long as we don't
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hit 0. )
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: ENDCASE
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BEGIN
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DUP NOT IF
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DROP COMPILE R> COMPILE DROP EXIT
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THEN
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[COMPILE] THEN
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AGAIN
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; IMMEDIATE
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: CREATE
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(entry) ( empty header with name )
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11 ( 11 == cellWord )
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C, ( write it )
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;
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( We run this when we're in an entry creation context. Many
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things we need to do.
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1. Change the code link to doesWord
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2. Leave 2 bytes for regular cell variable.
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3. Write down RS' RTOS to entry.
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4. exit parent definition
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)
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: DOES>
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( Overwrite cellWord in CURRENT )
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( 43 == doesWord )
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43 CURRENT @ C!
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( When we have a DOES>, we forcefully place HERE to 4
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bytes after CURRENT. This allows a DOES word to use ","
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and "C," without messing everything up. )
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CURRENT @ 3 + HERE !
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( HERE points to where we should write R> )
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R> ,
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( We're done. Because we've popped RS, we'll exit parent
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definition )
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;
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: VARIABLE CREATE 2 ALLOT ;
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: CONSTANT CREATE , DOES> @ ;
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: / /MOD SWAP DROP ;
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: MOD /MOD DROP ;
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( In addition to pushing H@ this compiles 2 >R so that loop
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variables are sent to PS at runtime )
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: DO
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COMPILE SWAP COMPILE >R COMPILE >R
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H@
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; IMMEDIATE
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( Increase loop counter and returns whether we should loop. )
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: _
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R> ( IP, keep for later )
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R> 1+ ( ip i+1 )
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DUP >R ( ip i )
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I' = ( ip f )
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SWAP >R ( f )
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;
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( One could think that we should have a sub word to avoid all
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these COMPILE, but we can't because otherwise it messes with
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the RS )
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: LOOP
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COMPILE _ COMPILE (?br)
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H@ - ,
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COMPILE R> COMPILE DROP COMPILE R> COMPILE DROP
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; IMMEDIATE
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: LEAVE R> R> DROP I 1- >R >R ;
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: ROLL
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DUP NOT IF EXIT THEN
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1+ DUP PICK ( n val )
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SWAP 2 * (roll) ( val )
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SWAP DROP
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;
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: 2DUP OVER OVER ;
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: 2OVER 3 PICK 3 PICK ;
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: 2SWAP 3 ROLL 3 ROLL ;
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( a1 a2 u -- )
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: MOVE
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( u ) 0 DO
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SWAP DUP I + C@ ( a2 a1 x )
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ROT SWAP OVER I + ( a1 a2 x a2 )
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C! ( a1 a2 )
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LOOP
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2DROP
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;
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: DELW
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1- 0 SWAP C!
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;
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: PREV
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3 - DUP @ ( a o )
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- ( a-o )
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;
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: WORD(
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DUP 1- C@ ( name len field )
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127 AND ( 0x7f. remove IMMEDIATE flag )
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3 + ( fixed header len )
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-
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;
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: FORGET
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' DUP ( w w )
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( HERE must be at the end of prev's word, that is, at the
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beginning of w. )
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WORD( HERE ! ( w )
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PREV CURRENT !
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;
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: EMPTY
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LIT< _sys (find) NOT IF ABORT THEN
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DUP HERE ! CURRENT !
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;
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( Drop RSP until I-2 == INTERPRET. )
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: EXIT!
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['] INTERPRET ( I )
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BEGIN ( I )
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DUP ( I I )
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R> DROP I 2- @ ( I I a )
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= UNTIL
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DROP
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;
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( a -- a+1 c )
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: C@+ DUP C@ SWAP 1+ SWAP ;
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