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forth2.fs_bak
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\
\ This is the core of Legs Forth
\
: true -1 ;
: false 0 ;
: noop ; \ a no operation
: cr d emit ; \ prints a cr
: space 20 emit ; \ prints a space
: ba here 0 , ; \ puts a back reference on stack
: imm 1 latest >flag ! ; \ mark latest word immediate
: then here swap ! ; imm \ then
: ' \ find a name
word find 0= 0bra [ ba ]
wnf quit then ;
: pp ' , ; imm \ compile word (ignoring imm flag)
: ^ lit lit , pp pp lit , , ; imm \ compile word ( later )
: if ^ 0bra ba ; imm \ if
: else ^ bra ba swap pp then ; imm \ else
: begin here ; imm \ begin
: again ^ bra , ; imm \ again
: until ^ 0bra , ; imm \ until
: while pp if ; imm \ while
: repeat swap pp again pp then ; imm \ repeat
: for ^ push here ^ dofor ba ; imm \ for
: next pp repeat ; imm \ next
: r@ rp@ cell+ @ ; \ copy top of return stack
: cell- cell - ; \ decriment TOS by a cell
\ ( a x -- a ) push a software stack
: -! swap cell- tuck ! ;
\ ( a b c -- b a c ) swap stack items 1 and 2
: 12swap rot swap ;
\ ( a b c -- c b a ) swap stack items 0 and 2
: 02swap -rot swap ;
: char? \ returns the ascii code for first letter in next word
^ lit word @+ drop c@ , ; imm
: ptib \ returns address of general parse buffer
tib 40 + ; \ locate past the word buffer
: parse \ ( c -- ca ) gets chars from input until char c is found
ptib 0 !+
begin over ekey tuck - while
c!+ 1 ptib +! repeat 3drop ptib ;
: ( \ embedded comment
char? ) parse drop ; imm
: slit pull dup @+ + push ; \ puts a string literal on stack
: " char? " parse ; \ makes a immediate mode string
: p" here " s, ; \ compiles a string
: s" ^ slit " s, ; imm \ comiles a string literal
: n" " @+ for c@+ c, next drop ; \ compiles just string bytes
\ append c to ca
: astr ( c ca -- )
dup push @+ + c! 1 pull +! ;
: defer ^ noop ; imm \ defers a word's definition
: [is] ( xt1 xt2 -- ) \ xt1 action is replace with xt2
!+ lit exit swap ! ;
: is ( xt "name" -- )
' swap [is] ;
: do&forget ( xt -- ) \ do xt and reset cp to before xt
dup exec cp ! ;
: xlit
pull @+ over + push ;
: [[ here ] ; \ starts a quote
: ]] pp ; ; imm \ ends a quote
: {{ \ strart compiled quote
^ xlit ba ; imm
: }} \ resolve compiled quote
^ exit here cell - over - swap ! ; imm
: type
@+ for c@+ emit next drop ;
: ." pp s" ^ type ; imm \ prints a string literal
: .( char? ) parse type ; imm \ prints a string literal
: utoc ( u -- c ) \ converts digit to ascii
dup a - 0< if 30 else 57 then + ;
: u. ( x -- ) \ print unsigned number
dup f and utoc swap shr shr shr shr ?dup if u. then emit ;
: . u. space cr ;
: depth sp@ 3f80 swap - shr ;
: bemit dup shr shr shr shr utoc emit f and utoc emit ;
: wemit sp@ dup c@ bemit char+ c@ bemit drop ;
: dump ( a -- ) \ dump memory
cr dup wemit ." :" cr
8 for
8 for
dup c@ bemit space char+
next
8 -
8 for
dup c@ dup bl? if drop 2e emit else emit then char+
next cr
next
cr drop
;
\
\ Replace the reset vector with
\ something nicer
\
[[ ." Legs Forth - 16 bit" cr ." ok" cr quit ]] 0 !
\
\ Replace WNF with a nicer version
\
[[ cr ." *** Word Not Found: " type cr bye ]] is wnf
: interact ( -- )
lit pp wnf {{ cr ." *** Word Not Found: " type cr quit }} [is] ;
: = xor 0= ; \ compares value to equality
: <> = com ; \ compares value for inequality
: u< 2dup xor 0< if nip 0< exit then - 0< ;
: u> swap u< ;
\ Signed Cell Compares
: < 2dup xor 0< if drop 0< exit then - 0< ;
: > swap < ;
: >= < com ;
: <= 2dup = -rot < or ;
\
\ for a *slightly* better interactive experience
\ make backspace do something
\ This replaces "word"
\
: bl? 21 u< ; \ this is used to make key that return -1 work!
\ ( -- ca ) \ get next word from input stream
[[
tib 0 !+
begin ekey dup bl? while drop repeat
\ exit with empty buffer if source closed
dup 0< if 2drop tib exit then
begin
dup 8 = here @ and if
drop 1- -1 tib +!
else
c!+ 1 tib +!
then
ekey dup dup dup bl? swap 8 <> and swap 0< or
until 2drop tib
]] is word
: docreate \ runs xt ( addr -- ) mem: docreate xt data....
r@ cell+ pull @ exec ;
: create ( "name" -- @xt ) \ creates a word that does something when called :)
header ^ docreate ^ exit ;
: does> ( -- ) \ resolves the xt address
pull latest >xt @ cell+ ! ;
: variable ( x "name" -- ) \ create a variable "name" init'd to x
create , ;
: constant ( x "name" -- ) \ create a constant "name" init'd to x
create , does> @ ;
\ this is not proper! *** it is implimentation dependent ***
: cells shl ;
: allot ( x -- ) \ allots x bytes to
here + cp ! ;
\ : salloc ( u -- a ) \ returns address of alloted bytes
\ here swap allot ;
\ : free ( a -- ) \ frees alloted bytes
\ drop
\ ;
\ ******************************************
\ Structures
\ ******************************************
: field ( u u -- u ) \ defines a field in a structure
over + swap create , does> @ + ;
: struct ( u -- ) \ defines a structure
constant ;
\ *************************************************
\ Vocabularies
\ *************************************************
create vstack 8 cells allot \ search order stack
latest \ stack last vocab word for breaking list apart
vstack variable vp \ vocabulary pointer
: vocabulary ( "name" -- ) \ creates a vocabulary
create 0 , does> vp @ ! ;
vocabulary legs \ these are the primitive definitions
vocabulary forth \ these are the base system
vocabulary vocab \ just the vocabulary words
0 variable compile-list \ where to compile new definitions
: also ( -- ) \ duplicates top of search stack
vp @ dup @ swap cell+ dup vp ! ! ;
: only ( -- ) \ reset vocabulary stack and vocabulary words
vstack vp ! vocab ;
: previous ( -- ) \ drops top of search stack
vp @ cell- vp ! ;
: definitions ( -- ) \ sets new definitions to go to top of search stack
vp @ @ compile-list ! ;
: words
vp @ begin
dup @ @ begin dup while dup >name type space @ repeat drop cr
cell- dup vstack u< until drop
;
: newfind ( ca -- ca 0 | xt 1 | xt -1 )
vp @ begin
2dup @ dfind ?dup if
\ return found ( ca vp da )
nip nip dup >xt @ swap >flag @ if 1 else -1 then exit then
cell- dup vstack u< until drop 0
;
: newdh ( -- lh ) \ new dh
compile-list @ ;
[[
\ redefine find
lit find lit newfind [is]
\ setup search list
only legs also forth definitions also vocab
\
\ split existing dictionary into three vocabularies
\
\ find first "forth" word
latest @ begin dup @ >xt @ ff u> while @ repeat
\ make it the head to the "legs" vocab
dup @ vstack @ ! 0 swap !
over dup @ vstack cell+ @ ! 0 swap !
\ make latest head to "vocab"
latest vstack cell+ cell+ @ !
\ redefine dh
lit dh lit newdh [is]
]] do&forget
only vocab also legs also forth definitions
\ ********************************************
\ Now We're gonna split the dictionary
\ and code area up.
\ ********************************************
cp0 constant host
host variable cpp \ pointer to code pointer
host variable dpp \ pointer to dictionary pointer
\ This is a new CP method
[[ cpp @ ]]
: dp dpp @ ;
: dhere dp @ ;
: d, dhere swap !+ dp ! ;
: dc, dhere swap c!+ dp ! ;
: ds, ( ca -- ) \ compile string to dictionary area
@+ dup d, for c@+ dc, next drop ;
\ This is a slighly modified "header"
\ to work with separate dictionary / compile areas
[[
dhere latest d, dh ! \ link
dhere 0 d, \ xt
0 d, \ compile blank flag
word ds, \ compile word new
here swap ! \ resolve xt
]]
\ install new methods
here host ! \ setup "host" cp
is header \ set new :
is cp \ set new cp
\ *************************************************
\ Local Names
\ This forth's "locals" doesn't refer to stack data
\ "locals" refers to local word definitions
\ for creating temporily named "helper" words
\ *************************************************
memz 500 - constant localarea \ The start of the local headers area
localarea variable lp \ the local header pointer (like CP )
vocabulary localdefs \ and the list head
\ This starts a "local block" - all definitions headers will be
\ compiled to a separate area, and linked in to the localdefs
\ vocabulary
: { ( -- lp lh )
also localdefs definitions \ add search list and compile vocab
lp dpp ! \ compile headers to local area
lp @ \ copy of lp for later reversion
vp @ @ @ \ copy of list head for later revert
;
\ Pulic changes the compile area back to regular - but leaves the
\ newly defined locals findable
: public ( -- )
previous definitions also localdefs \ change compile list to reg
host dpp ! \ compile headers back to host area
;
\ and this ends the local block, it earses the headers of the
\ locals ( not the code ) and resets the list head
: } ( lp lh -- )
vp @ @ ! \ restore local list head
lp ! \ restore localarea pointer
previous definitions \ change search list back
host dpp ! \ compile header back to host area
;
\ ***************************************
\ memory move, compare, fill
\ ***************************************
: mv ( d s u -- ) \ move u bytes at a1 to a2
for c@+ 12swap c!+ swap next 2drop ;
: cmp ( a1 a2 u -- f ) \ compare u bytes
for c@+ push swap c@+ pull <> if 2drop false unloop exit then next
2drop true ;
\ ***************************************
\ Simple run-time debug
\ ***************************************
: de. ( -- "out" ) \ prints debug and stack depth
." debug: " depth . cr sp@ dump ;
\ ******************************
\ Dynamic Memory Allocation
\ ******************************
{
0
cell field >next
cell field >flags
struct mlist
: size ( a -- u ) \ returns effective size of chunk
dup @ swap - mlist - ;
: >data ( a -- a ) \ return chunk data field address
mlist + ;
: >ca ( a -- a ) \ converts a data field address to chunk address
mlist - ;
: mark ( a -- ) \ marks chunk as used
>flags dup @ mint or swap ! ;
: unmark ( a -- ) \ marks chunk as free
>flags dup @ mint com and swap ! ;
: used? ( a -- f ) \ returns true if chunk is used
>flags @ 0< ;
: free? ( a -- f ) \ returns true if chunk is free
used? 0= ;
: last? ( a -- f ) \ returns true if chunk is last in list
@ @ 0= ;
: nconsol ( a -- ) \ consolidates chunk with next chunk
dup @ @ swap ! ;
: split ( u a -- ) \ split chunk to u bytes
tuck + mlist + \ calc new chunk address ( a n )
dup unmark \ mark new chunk as free ( a n )
over @ over ! \ init new chunks next field ( a n )
swap ! \ mod parent chunk's next field
;
: find ( u a1 -- a2 ) \ find node big enough for u bytes
begin 2dup size u> 0= over free? and if nip exit then
dup last? 0= while @ repeat 2drop false ;
: compact ( a -- ) \ compact heap list
begin dup last? 0= while
dup free? over @ free? and if dup nconsol else @ then
repeat drop ;
public
\ allocate u bytes of data on a heap starting with
\ node address a1
: alloc ( u a1 -- a2 )
2dup find ( u a a )
\ if no chunk big enough then compact
\ and try again
dup 0= if drop dup compact
2dup find ( u a a )
dup 0= if nip nip exit then
then
\ mark chunk as used
nip dup mark
\ split chunk if big enough
2dup size swap - mlist cell+ u> if 2dup split then
\ return data field
nip >data
;
\ dallocate dynamic memory a
: free ( a -- )
dup >ca free? if ." dup free!" cr drop exit then
?dup 0= if exit then >ca unmark ;
: .h ( a -- ) \ print heap
begin
dup wemit space dup size wemit space dup @ wemit space dup used? wemit cr
dup last? 0= while @
repeat drop ;
\ address size
}
\ allots and inits named chunk
: dchunk ( u "name" -- ) \ initialize chunks
create ba false , swap allot here swap ! false , ;
600 dchunk heap
: salloc ( u -- a ) \ allocate system heap
heap alloc ?dup 0= if ." out of memory" cr quit then
;
: .heap
heap .h ;
: debug ( x -- ) \ print debug message
." debug " . ;
\ ***********************************
\ objects
\ ***********************************
0
cell field >csize \ size of this class structure
cell field >msize \ size of object's member data
cell field >parent \ ptr to parent's class struct
cell field >vocab \ class's vocabulary (linked with parent's)
0 field >vmt \ Method table ( array of xt's )
struct class
create vmt 32 cells allot \ class assembly area
0 variable obj \ run-time object pointer
0 variable ovp \ saved vp pointer
: calloc ( u -- a ) \ compile alloc
here swap allot ;
: redef ( xt "name" -- ) \ redefined a dictionary xt
word
vp @ begin
2dup @ dfind ?dup if
\ if found ( xt ca vp da )
nip nip >xt ! exit then
cell- dup vstack u< until
;
: svvp ( -- ) \ saves vp in ovp var
vp @ ovp ! ;
[[ svvp : ]] redef :
[[ ovp @ vp ! pp ; ]] redef ;
: self ( -- object ) \ puts self-object on stack
obj @ ;
: method ( "name" -- ) ( x*i obj -- x*j )
svvp
\ play with the class assembly area
create vmt @ , \ create name to offset
here vmt dup @ + ! \ set xt in vmt
cell vmt +! \ increment vmt size
] \ start compiling method
\ make a run-time action for new method
does> self push @ swap dup obj ! @ + @ exec pull obj ! ;
: member ( size "name" -- ) ( -- a )
create vmt >msize @ , \ create name with offset
vmt >msize +! \ incrmenet vmt member size
\ make a run-time action for new member
does> @ self + ;
: use ( "class" -- ) \ use a class vocabulary
pp ' exec also >vocab vp @ ! ; imm
: flz ( -- ) ( -- class ) \ finalizes a class
previous definitions
vmt @ calloc dup vmt vmt @ mv ;
: class ( "name" -- ) ( -- class ) \ finalizes class and names
flz constant
;
: extend ( class -- ) \ copies class to class building area
dup
vmt swap dup @ mv \ copy class struct
vmt >parent ! \ fill in new class's parant ptr
also vmt >vocab vp @ ! \ use new vocabulary
definitions
;
: as ( "name" -- ) \ overrides parent method
svvp here vmt pp ' cell+ cell+ @ + ! ] ;
: parent ( "name" -- ) \ compiles parent's method
pull dup cell+ push @
self dup @ dup push >parent @ swap !
exec pull self ! ;
\
\ a hand-build base object class
\
vmt
4 cells !+ \ class size
cell !+ \ member size
0 !+ \ parent class ( NULL in obj's case )
0 !+ \ vocab head
also vmt >vocab vp @ ! definitions \ use new vocab
method init true ; ( -- f ) \ initializes object
method deinit true ; ( -- f ) \ deinitializes object
class obj
: new ( i*x class -- object ) \ makes an object
use obj
dup >msize @ salloc tuck !
dup push init if pull exit then
pull free false
;
: destroy ( object -- ) \ destroys an object
use obj
dup deinit if free else drop then
;
: single ( "name" -- ) \ finalizes class and creates a signalton object
flz new constant
;
\ **********************************
\ Abstract Containers
\ **********************************
obj extend
method add ; ( item -- ) \ add an object to the container
method giter ; ( -- iter ) \ get an iterater object for the container
method no ; ( -- u ) \ number of items in container
class container
obj extend
method next? ; ( -- f ) \ is there another value?
method inext ; ( -- ) \ position to new value
method gitem ; ( -- item ) \ get item
class iter
\ xt ( item -- f )
: iforeach ( iter xt -- f ) \ iterate through container
use iter
swap
begin dup next? while
2dup push push gitem swap exec
if pull pull 2drop true exit then
pull pull dup inext
repeat 2drop false ;
\ xt ( item -- f )
: foreach ( container xt -- item | 0 ) \ iterate through container
use container use iter
swap giter dup push swap iforeach
if r@ gitem
else false
then pull destroy ;
\ C-Str container class
iter extend
cell member base
cell member count
as init ( ca -- f )
dup cell+ base ! @ count ! true ;
as next? ( -- f )
count @ ;
as inext ( -- )
1 base +! -1 count +! ;
as gitem ( -- c )
base @ c@ ;
class citer
container extend
cell member base
as init ( ca -- f )
base ! true ;
as add ( item -- )
drop ." Cannot add to this container." quit ;
as giter ( -- iter )
base @ citer new ;
class cstr
\ *********************************
\ Sinple Linked List Container
\ *********************************
obj extend
cell member nexti \ ptr to next list item
method snext ( a -- ) \ set ptr to next list item
nexti ! ;
method gnext ( -- a ) \ get ptr to next list item
nexti @ ;
class litem
iter extend
cell member addr \ the current addr
as init ( head -- f ) \ init an iterator
addr ! true ;
as next? ( -- f ) \ is there another value?
addr @ ;
as inext ( -- ) \ position to new value
use litem
addr @ gnext addr ! ;
as gitem ( -- item ) \ get item
addr @ ;
class liter
container extend
cell member head \ head of list
cell member count \ number of items
as init ( -- f )
0 count ! 0 head ! true ;
as add ( litem -- f )
use litem
1 count +! dup head @ swap snext head ! ;
as giter ( head -- iter )
head @ liter new ;
as no ( -- u )
count @ ;
class llist
\ ****************************
\ Associative List
\ ****************************
litem extend
cell member key
as init ( llist ca -- f )
use llist
key ! self swap add
true
;
method gkey ( -- ca )
key @ ;
class aitem
\ find item by key
: findbykey ( ca llist -- aitem | 0 )
use aitem
{{ gkey over s= }} foreach nip ;
\ list assoc list's key value's
: listkey ( llist -- )
use aitem
cr {{ dup u. space gkey type cr false }} foreach drop cr ;
\ ***********************************
\ Block Device Objects
\ ***********************************
0
cell field >low
cell field >high
cell field >drive
cell field >device
struct baddr
llist new constant cdevs
aitem extend
as init ( ca -- f ) \ init charactor device
cdevs swap self parent init ;
method get ( -- c ) ; \ get charactor
method put ( c -- ) ; \ put charactor
class cdev
\ ****************************************
\ Becker Character Device
\ ****************************************
cdev extend
as put ( c -- ) \ send a byte via becker port
ff42 p! ;
as get ( -- c ) \ receive a byte via becker port
begin ff41 p@ until ff42 p@ ;
class becker
\ **********************************
\ Block Devices
\ **********************************
llist new constant bdevs
aitem extend
as init ( ca -- f ) \ init block device
bdevs swap self parent init ;
method get ( baddr a -- f ) ; \ get sector
method put ( baddr a -- f ) ; \ put sector
class bdev
\ *********************************
\ DriveWire 4 block device
\ *********************************
bdev extend
cell member device \ which charactor device to use
as init ( ca_name ca_cdev -- f )
cdevs findbykey device !
self parent init ;
: bkr! ( c -- )
use cdev device @ put ;
: bkr@ ( -- c )
use cdev device @ get ;
: cksum ( addr -- x ) \ compute a 256 byte checksum
0 swap 100 for c@+ rot + swap next drop ;
as get ( baddr a -- f ) \ get a drive sector
swap
\ send op
d2 bkr! \ send drive readop
dup >drive @ bkr! \ send drive no
dup >high @ bkr! \ send hi sector
>low c@+ bkr! \ send low sector msb
c@ bkr! \ send low sector lsb
\ recieve
dup 100 for bkr@ c!+ next drop
cksum sp@ c@+ bkr! c@ bkr! drop
bkr@
;
as put ( baddr a -- f ) \ This just returns an error
2drop false ;
class dw4
\ ************************************
\ Caching
\ ************************************
100 constant sector \ size of a disk sector
llist new constant cache \ list of cobs
litem extend {
sector member data \ databuffer
baddr member addr \ address of cob
cell member count \ lock count
cell member time \ time of release
0 variable rtimer \ release timer
: fill ( -- ) \ fill cob's data buffer
use bdev addr data over >device @ get drop ;
public
method reassign ( baddr -- ) \ reassign
addr swap baddr mv \ copy addr
fill \ fill data from device driver
1 count ! \ set count to 1 lock
0 time ! \ reset time
;
as init ( baddr -- f )
self reassign
use container
self cache add \ add self to cache
true
;
method lock ( -- ) \ obtain lock on cob
1 count +! ;
method rel ( -- ) \ release lock on cob
count @ 1- dup count !
0= if rtimer @ 1+ dup rtimer ! time ! then
;
method daddr ( -- a ) \ return ptr to data
data ;
method rtime ( -- u ) \ return time of release
time @ ;
method free? ( -- f ) \ returns true if cob is free
count @ 0= ;
method ccmp ( baddr -- f ) \ return true if baddr=addr
addr baddr cmp ;
} class cob
{
: csearch ( baddr -- cob | 0 ) \ search for matching cob
use cob
cache {{ over swap ccmp }} foreach nip ;
: free ( -- cob | 0 ) \ search for free cob
use cob
\ find a free cob
cache {{ free? }} foreach dup 0= if exit then
\ search list for a free and older cob x
cache {{ over rtime over rtime u> over free? and
if swap then drop false }} foreach drop
;
: 4nip ( dev dri high low x -- x ) \ nip 4 times
nip nip nip nip ;
public
4 variable cmax \ maximum cobs in a cache
: getc ( dev dri high low -- cob | 0 ) \ get a cob
sp@
use cob use llist
\ if cache hit then return
dup csearch ?dup if 4nip nip dup lock exit then
\ if cache is less than max size then return with new cob
cache no cmax @ u< if cob new 4nip exit then
\ find an old unuse cob and reuse
free ?dup if tuck reassign 4nip exit then
\ and if cache is full on used cobs:
." Error: Cache full!" 4nip drop cr quit
;
\ x x x x cob baddr cob
: relc ( cob -- ) \ releases a cob
use cob ?dup if rel then ;
}
\ ****************************
\ Filesystem Class
\ ****************************
llist new constant mounts
aitem extend
cell member drive \ drive no that the fs sits on
cell member device \ device that the fs sits on
cell member count \ how many open files
\ init this filesystem under the name ca on device and drive no
as init ( device drive ca -- f )
mounts swap self parent init drop
drive ! device !
0 count !
true ;
as deinit ( -- f )
count @ if ." FS is busy!" cr false else true ;
method fsgetc ( d d -- cob ) \ get a cob
swap device @ -rot drive @ -rot getc ;
method iopen ( d d -- file ) \ open an inode by number
1 count +! ;