mirror of
https://github.com/hsoft/collapseos.git
synced 2024-12-26 03:28:05 +11:00
forth: clarify the meaning of "wordref"
Also, make entry labels in dict.asm be wordref instead of entry ref.
This commit is contained in:
Virgil Dupras
parent
e8a4768304
commit
0e8af3cea4
@ -13,11 +13,8 @@
|
||||
nativeWord:
|
||||
jp (iy)
|
||||
|
||||
; Execute a compiled word containing a list of references to other words,
|
||||
; usually ended by a reference to EXIT.
|
||||
; A reference to a word in a compiledWord section is *not* a direct reference,
|
||||
; but a word+CODELINK_OFFSET reference. Therefore, for a code link "link",
|
||||
; (link) is the routine to call.
|
||||
; Execute a list of atoms, which usually ends with EXIT.
|
||||
; IY points to that list.
|
||||
compiledWord:
|
||||
push iy \ pop hl
|
||||
inc hl
|
||||
@ -86,7 +83,7 @@ elseWord:
|
||||
inc bc \ inc bc
|
||||
call intoHL
|
||||
or a ; clear carry
|
||||
ld de, EXIT+CODELINK_OFFSET
|
||||
ld de, EXIT
|
||||
sbc hl, de
|
||||
jp z, exit
|
||||
; Not EXIT, let's continue with ELSE. No carry possible because EXIT
|
||||
@ -152,10 +149,10 @@ LIT:
|
||||
.dw litWord
|
||||
|
||||
; ( R:I -- )
|
||||
EXIT:
|
||||
.db ";"
|
||||
.fill 7
|
||||
.dw 0
|
||||
EXIT:
|
||||
.dw nativeWord
|
||||
; When we call the EXIT word, we have to do a "double exit" because our current
|
||||
; Interpreter pointer is pointing to the word *next* to our EXIT reference when,
|
||||
@ -171,26 +168,26 @@ exit:
|
||||
jp compiledWord
|
||||
|
||||
; ( R:I -- )
|
||||
QUIT:
|
||||
.db "QUIT", 0, 0, 0, 0
|
||||
.dw EXIT
|
||||
QUIT:
|
||||
.dw nativeWord
|
||||
quit:
|
||||
jp forthRdLine
|
||||
|
||||
ABORT:
|
||||
.db "ABORT", 0, 0, 0
|
||||
.dw QUIT
|
||||
ABORT:
|
||||
.dw nativeWord
|
||||
abort:
|
||||
; Reinitialize PS (RS is reinitialized in forthInterpret
|
||||
ld sp, (INITIAL_SP)
|
||||
jp forthRdLine
|
||||
|
||||
BYE:
|
||||
.db "BYE"
|
||||
.fill 5
|
||||
.dw ABORT
|
||||
BYE:
|
||||
.dw nativeWord
|
||||
; Goodbye Forth! Before we go, let's restore the stack
|
||||
ld sp, (INITIAL_SP)
|
||||
@ -201,9 +198,9 @@ BYE:
|
||||
ret
|
||||
|
||||
; ( c -- )
|
||||
EMIT:
|
||||
.db "EMIT", 0, 0, 0, 0
|
||||
.dw BYE
|
||||
EMIT:
|
||||
.dw nativeWord
|
||||
pop hl
|
||||
ld a, l
|
||||
@ -211,13 +208,11 @@ EMIT:
|
||||
jp exit
|
||||
|
||||
; ( addr -- )
|
||||
EXECUTE:
|
||||
.db "EXECUTE", 0
|
||||
.dw EMIT
|
||||
EXECUTE:
|
||||
.dw nativeWord
|
||||
pop iy ; Points to word_offset
|
||||
ld de, CODELINK_OFFSET
|
||||
add iy, de
|
||||
pop iy ; is a wordref
|
||||
executeCodeLink:
|
||||
ld l, (iy)
|
||||
ld h, (iy+1)
|
||||
@ -227,10 +222,10 @@ executeCodeLink:
|
||||
; IY points to PFA
|
||||
jp (hl) ; go!
|
||||
|
||||
DEFINE:
|
||||
.db ":"
|
||||
.fill 7
|
||||
.dw EXECUTE
|
||||
DEFINE:
|
||||
.dw nativeWord
|
||||
call entryhead
|
||||
ld de, compiledWord
|
||||
@ -272,9 +267,9 @@ DEFINE:
|
||||
ld (HERE), de ; update HERE
|
||||
jp exit
|
||||
|
||||
DOES:
|
||||
.db "DOES>", 0, 0, 0
|
||||
.dw DEFINE
|
||||
DOES:
|
||||
.dw nativeWord
|
||||
; We run this when we're in an entry creation context. Many things we
|
||||
; need to do.
|
||||
@ -285,8 +280,6 @@ DOES:
|
||||
; 3. exit. Because we've already popped RS, a regular exit will abort
|
||||
; colon definition, so we're good.
|
||||
ld iy, (CURRENT)
|
||||
ld de, CODELINK_OFFSET
|
||||
add iy, de
|
||||
ld hl, doesWord
|
||||
call wrCompHL
|
||||
inc iy \ inc iy ; cell variable space
|
||||
@ -296,10 +289,10 @@ DOES:
|
||||
jp exit
|
||||
|
||||
; ( -- c )
|
||||
KEY:
|
||||
.db "KEY"
|
||||
.fill 5
|
||||
.dw DOES
|
||||
KEY:
|
||||
.dw nativeWord
|
||||
call stdioGetC
|
||||
ld h, 0
|
||||
@ -307,9 +300,9 @@ KEY:
|
||||
push hl
|
||||
jp exit
|
||||
|
||||
INTERPRET:
|
||||
.db "INTERPRE"
|
||||
.dw KEY
|
||||
INTERPRET:
|
||||
.dw nativeWord
|
||||
interpret:
|
||||
ld iy, COMPBUF
|
||||
@ -319,14 +312,14 @@ interpret:
|
||||
call compile
|
||||
jr .loop
|
||||
.end:
|
||||
ld hl, QUIT+CODELINK_OFFSET
|
||||
ld hl, QUIT
|
||||
call wrCompHL
|
||||
ld iy, COMPBUF
|
||||
jp compiledWord
|
||||
|
||||
CREATE:
|
||||
.db "CREATE", 0, 0
|
||||
.dw INTERPRET
|
||||
CREATE:
|
||||
.dw nativeWord
|
||||
call entryhead
|
||||
jp nz, quit
|
||||
@ -338,24 +331,24 @@ CREATE:
|
||||
ld (HERE), hl
|
||||
jp exit
|
||||
|
||||
HERE_: ; Caution: conflicts with actual variable name
|
||||
.db "HERE"
|
||||
.fill 4
|
||||
.dw CREATE
|
||||
HERE_: ; Caution: conflicts with actual variable name
|
||||
.dw sysvarWord
|
||||
.dw HERE
|
||||
|
||||
CURRENT_:
|
||||
.db "CURRENT", 0
|
||||
.dw HERE_
|
||||
CURRENT_:
|
||||
.dw sysvarWord
|
||||
.dw CURRENT
|
||||
|
||||
; ( n -- )
|
||||
DOT:
|
||||
.db "."
|
||||
.fill 7
|
||||
.dw CURRENT_
|
||||
DOT:
|
||||
.dw nativeWord
|
||||
pop de
|
||||
; We check PS explicitly because it doesn't look nice to spew gibberish
|
||||
@ -367,10 +360,10 @@ DOT:
|
||||
jp exit
|
||||
|
||||
; ( n a -- )
|
||||
STORE:
|
||||
.db "!"
|
||||
.fill 7
|
||||
.dw DOT
|
||||
STORE:
|
||||
.dw nativeWord
|
||||
pop iy
|
||||
pop hl
|
||||
@ -379,10 +372,10 @@ STORE:
|
||||
jp exit
|
||||
|
||||
; ( a -- n )
|
||||
FETCH:
|
||||
.db "@"
|
||||
.fill 7
|
||||
.dw STORE
|
||||
FETCH:
|
||||
.dw nativeWord
|
||||
pop hl
|
||||
call intoHL
|
||||
@ -390,10 +383,10 @@ FETCH:
|
||||
jp exit
|
||||
|
||||
; ( a b -- b a )
|
||||
SWAP:
|
||||
.db "SWAP"
|
||||
.fill 4
|
||||
.dw FETCH
|
||||
SWAP:
|
||||
.dw nativeWord
|
||||
pop hl
|
||||
ex (sp), hl
|
||||
@ -401,10 +394,10 @@ SWAP:
|
||||
jp exit
|
||||
|
||||
; ( a -- a a )
|
||||
DUP:
|
||||
.db "DUP"
|
||||
.fill 5
|
||||
.dw SWAP
|
||||
DUP:
|
||||
.dw nativeWord
|
||||
pop hl
|
||||
push hl
|
||||
@ -412,10 +405,10 @@ DUP:
|
||||
jp exit
|
||||
|
||||
; ( a b -- a b a )
|
||||
OVER:
|
||||
.db "OVER"
|
||||
.fill 4
|
||||
.dw DUP
|
||||
OVER:
|
||||
.dw nativeWord
|
||||
pop hl ; B
|
||||
pop de ; A
|
||||
@ -425,10 +418,10 @@ OVER:
|
||||
jp exit
|
||||
|
||||
; ( a b -- c ) A + B
|
||||
PLUS:
|
||||
.db "+"
|
||||
.fill 7
|
||||
.dw OVER
|
||||
PLUS:
|
||||
.dw nativeWord
|
||||
pop hl
|
||||
pop de
|
||||
@ -437,10 +430,10 @@ PLUS:
|
||||
jp exit
|
||||
|
||||
; ( a b -- c ) A - B
|
||||
MINUS:
|
||||
.db "-"
|
||||
.fill 7
|
||||
.dw PLUS
|
||||
MINUS:
|
||||
.dw nativeWord
|
||||
pop de ; B
|
||||
pop hl ; A
|
||||
@ -450,10 +443,10 @@ MINUS:
|
||||
jp exit
|
||||
|
||||
; ( a b -- c ) A * B
|
||||
MULT:
|
||||
.db "*"
|
||||
.fill 7
|
||||
.dw MINUS
|
||||
MULT:
|
||||
.dw nativeWord
|
||||
pop de
|
||||
pop bc
|
||||
@ -462,10 +455,10 @@ MULT:
|
||||
jp exit
|
||||
|
||||
; ( a b -- c ) A / B
|
||||
DIV:
|
||||
.db "/"
|
||||
.fill 7
|
||||
.dw MULT
|
||||
DIV:
|
||||
.dw nativeWord
|
||||
pop de
|
||||
pop hl
|
||||
@ -473,83 +466,83 @@ DIV:
|
||||
push bc
|
||||
jp exit
|
||||
|
||||
IF:
|
||||
.db "IF"
|
||||
.fill 6
|
||||
.dw DIV
|
||||
IF:
|
||||
.dw ifWord
|
||||
|
||||
ELSE:
|
||||
.db "ELSE"
|
||||
.fill 4
|
||||
.dw IF
|
||||
ELSE:
|
||||
.dw elseWord
|
||||
|
||||
THEN:
|
||||
.db "THEN"
|
||||
.fill 4
|
||||
.dw ELSE
|
||||
THEN:
|
||||
.dw thenWord
|
||||
|
||||
; End of native words
|
||||
|
||||
; ( a -- )
|
||||
; @ .
|
||||
FETCHDOT:
|
||||
.db "?"
|
||||
.fill 7
|
||||
.dw THEN
|
||||
FETCHDOT:
|
||||
.dw compiledWord
|
||||
.dw FETCH+CODELINK_OFFSET
|
||||
.dw DOT+CODELINK_OFFSET
|
||||
.dw EXIT+CODELINK_OFFSET
|
||||
.dw FETCH
|
||||
.dw DOT
|
||||
.dw EXIT
|
||||
|
||||
; ( n a -- )
|
||||
; SWAP OVER @ + SWAP !
|
||||
STOREINC:
|
||||
.db "+!"
|
||||
.fill 6
|
||||
.dw FETCHDOT
|
||||
STOREINC:
|
||||
.dw compiledWord
|
||||
.dw SWAP+CODELINK_OFFSET
|
||||
.dw OVER+CODELINK_OFFSET
|
||||
.dw FETCH+CODELINK_OFFSET
|
||||
.dw PLUS+CODELINK_OFFSET
|
||||
.dw SWAP+CODELINK_OFFSET
|
||||
.dw STORE+CODELINK_OFFSET
|
||||
.dw EXIT+CODELINK_OFFSET
|
||||
.dw SWAP
|
||||
.dw OVER
|
||||
.dw FETCH
|
||||
.dw PLUS
|
||||
.dw SWAP
|
||||
.dw STORE
|
||||
.dw EXIT
|
||||
|
||||
; ( n -- )
|
||||
; HERE +!
|
||||
ALLOT:
|
||||
.db "ALLOT", 0, 0, 0
|
||||
.dw STOREINC
|
||||
ALLOT:
|
||||
.dw compiledWord
|
||||
.dw HERE_+CODELINK_OFFSET
|
||||
.dw STOREINC+CODELINK_OFFSET
|
||||
.dw EXIT+CODELINK_OFFSET
|
||||
.dw HERE_
|
||||
.dw STOREINC
|
||||
.dw EXIT
|
||||
|
||||
; CREATE 2 ALLOT
|
||||
VARIABLE:
|
||||
.db "VARIABLE"
|
||||
.dw ALLOT
|
||||
VARIABLE:
|
||||
.dw compiledWord
|
||||
.dw CREATE+CODELINK_OFFSET
|
||||
.dw CREATE
|
||||
.dw NUMBER
|
||||
.dw 2
|
||||
.dw ALLOT+CODELINK_OFFSET
|
||||
.dw EXIT+CODELINK_OFFSET
|
||||
.dw ALLOT
|
||||
.dw EXIT
|
||||
|
||||
; ( n -- )
|
||||
; CREATE HERE @ ! DOES> @
|
||||
CONSTANT:
|
||||
.db "CONSTANT"
|
||||
.dw VARIABLE
|
||||
CONSTANT:
|
||||
.dw compiledWord
|
||||
.dw CREATE+CODELINK_OFFSET
|
||||
.dw HERE_+CODELINK_OFFSET
|
||||
.dw FETCH+CODELINK_OFFSET
|
||||
.dw STORE+CODELINK_OFFSET
|
||||
.dw DOES+CODELINK_OFFSET
|
||||
.dw FETCH+CODELINK_OFFSET
|
||||
.dw EXIT+CODELINK_OFFSET
|
||||
.dw CREATE
|
||||
.dw HERE_
|
||||
.dw FETCH
|
||||
.dw STORE
|
||||
.dw DOES
|
||||
.dw FETCH
|
||||
.dw EXIT
|
||||
|
||||
@ -1,19 +1,29 @@
|
||||
Stack notation: "<stack before> -- <stack after>". Rightmost is top of stack
|
||||
(TOS). For example, in "a b -- c d", b is TOS before, d is TOS
|
||||
after. "R:" means that the Return Stack is modified.
|
||||
(TOS). For example, in "a b -- c d", b is TOS before, d is TOS after. "R:" means
|
||||
that the Return Stack is modified.
|
||||
|
||||
DOES>: Used inside a colon definition that itself uses CREATE, DOES> transforms
|
||||
that newly created word into a "does cell", that is, a regular cell (
|
||||
when called, puts the cell's addr on PS), but right after that, it
|
||||
executes words that appear after the DOES>.
|
||||
that newly created word into a "does cell", that is, a regular cell ( when
|
||||
called, puts the cell's addr on PS), but right after that, it executes words
|
||||
that appear after the DOES>.
|
||||
|
||||
"does cells" always allocate 4 bytes (2 for the cell, 2 for the DOES>
|
||||
link) and there is no need for ALLOT in colon definition.
|
||||
"does cells" always allocate 4 bytes (2 for the cell, 2 for the DOES> link) and
|
||||
there is no need for ALLOT in colon definition.
|
||||
|
||||
At compile time, colon definition stops processing words when reaching
|
||||
the DOES>.
|
||||
At compile time, colon definition stops processing words when reaching the
|
||||
DOES>.
|
||||
|
||||
Example: ": CONSTANT CREATE HERE @ ! DOES> @ ;"
|
||||
Example: ": CONSTANT CREATE HERE @ ! DOES> @ ;"
|
||||
|
||||
Word references (wordref): When we say we have a "word reference", it's a
|
||||
pointer to a words *code link*. For example, the label "PLUS:" in this unit is a
|
||||
word reference. Why not refer to the beginning of the word struct? Because we
|
||||
actually seldom refer to the name and prev link, except during compilation, so
|
||||
defining "word reference" this way makes the code easier to understand.
|
||||
|
||||
Atom: A word of the type compiledWord contains, in its PF, a list of what we
|
||||
call "atoms". Those atoms are most of the time word references, but they can
|
||||
also be references to NUMBER and LIT.
|
||||
|
||||
*** Native Words ***
|
||||
|
||||
@ -27,11 +37,12 @@ DOES>: Used inside a colon definition that itself uses CREATE, DOES> transforms
|
||||
* a b -- c a * b -> c
|
||||
/ a b -- c a / b -> c
|
||||
CREATE x -- Create cell named x. Doesn't allocate a PF.
|
||||
CURRENT -- n Set n to wordref of last added entry.
|
||||
DOES> -- See description at top of file
|
||||
DUP a -- a a
|
||||
ELSE -- Branch to THEN
|
||||
EMIT c -- Spit char c to stdout
|
||||
EXECUTE a -- Execute word at addr a
|
||||
EXECUTE a -- Execute wordref at addr a
|
||||
HERE -- a Push HERE's address
|
||||
IF n -- Branch to ELSE or THEN if n is zero
|
||||
QUIT R:drop -- Return to interpreter promp immediately
|
||||
|
||||
@ -6,7 +6,7 @@
|
||||
; Max length of dict entry names
|
||||
.equ NAMELEN 8
|
||||
; Offset of the code link relative to the beginning of the word
|
||||
.equ CODELINK_OFFSET 10
|
||||
.equ CODELINK_OFFSET NAMELEN+2
|
||||
|
||||
; *** Variables ***
|
||||
.equ INITIAL_SP FORTH_RAMSTART
|
||||
@ -39,7 +39,7 @@ forthRdLine:
|
||||
ld (INPUTPOS), hl
|
||||
forthInterpret:
|
||||
ld ix, RS_ADDR-2 ; -2 because we inc-before-push
|
||||
ld iy, INTERPRET+CODELINK_OFFSET
|
||||
ld iy, INTERPRET
|
||||
jp executeCodeLink
|
||||
msgOk:
|
||||
.db " ok", 0
|
||||
|
||||
@ -80,7 +80,7 @@ RSIsLIT:
|
||||
; Z if yes, NZ if no.
|
||||
RSIsEXIT:
|
||||
push de
|
||||
ld de, EXIT+CODELINK_OFFSET
|
||||
ld de, EXIT
|
||||
call RSIsDE
|
||||
pop de
|
||||
ret
|
||||
@ -163,14 +163,10 @@ readCompWord:
|
||||
.msg:
|
||||
.db "word expected", 0
|
||||
|
||||
; For DE pointing to a dict entry, set DE to point to the previous entry.
|
||||
; For DE being a wordref, move DE to the previous wordref.
|
||||
; Z is set if DE point to 0 (no entry). NZ if not.
|
||||
prev:
|
||||
push hl ; --> lvl 1
|
||||
ld hl, NAMELEN ; prev field offset
|
||||
add hl, de
|
||||
ex de, hl
|
||||
pop hl ; <-- lvl 1
|
||||
dec de \ dec de ; prev field
|
||||
call intoDE
|
||||
; DE points to prev. Is it zero?
|
||||
xor a
|
||||
@ -183,15 +179,28 @@ prev:
|
||||
; point to that entry.
|
||||
; Z if found, NZ if not.
|
||||
find:
|
||||
push hl
|
||||
push bc
|
||||
ld de, (CURRENT)
|
||||
ld bc, CODELINK_OFFSET
|
||||
.inner:
|
||||
; DE is a wordref, let's go to beginning of struct
|
||||
push de ; --> lvl 1
|
||||
or a ; clear carry
|
||||
ex de, hl
|
||||
sbc hl, bc
|
||||
ex de, hl ; We're good, DE points to word name
|
||||
ld a, NAMELEN
|
||||
call strncmp
|
||||
ret z ; found
|
||||
pop de ; <-- lvl 1, return to wordref
|
||||
jr z, .end ; found
|
||||
call prev
|
||||
jr nz, .inner
|
||||
; Z set? end of dict unset Z
|
||||
inc a
|
||||
.end:
|
||||
pop bc
|
||||
pop hl
|
||||
ret
|
||||
|
||||
; Write compiled data from HL into IY, advancing IY at the same time.
|
||||
@ -207,10 +216,7 @@ wrCompHL:
|
||||
compile:
|
||||
call find
|
||||
jr nz, .maybeNum
|
||||
; DE is a word offset, we need a code link
|
||||
ld hl, CODELINK_OFFSET
|
||||
add hl, de
|
||||
xor a ; set Z
|
||||
ex de, hl
|
||||
jr wrCompHL
|
||||
.maybeNum:
|
||||
push hl ; --> lvl 1. save string addr
|
||||
@ -250,13 +256,13 @@ entryhead:
|
||||
call strcpy
|
||||
ex de, hl ; (HERE) now in HL
|
||||
ld de, (CURRENT)
|
||||
ld (CURRENT), hl
|
||||
ld a, NAMELEN
|
||||
call addHL
|
||||
ld (hl), e
|
||||
inc hl
|
||||
ld (hl), d
|
||||
inc hl
|
||||
ld (CURRENT), hl
|
||||
ld (HERE), hl
|
||||
xor a ; set Z
|
||||
ret
|
||||
|
||||
Loading…
Reference in New Issue
Block a user