historical/m0-applesillicon.git/xnu-qemu-arm64-5.1.0/roms/openbios/forth/device/fcode.fs
2024-01-16 11:20:27 -06:00

573 lines
9.4 KiB
Forth

\ tag: FCode implementation functions
\
\ this code implements IEEE 1275-1994 ch. 5.3.3
\
\ Copyright (C) 2003 Stefan Reinauer
\
\ See the file "COPYING" for further information about
\ the copyright and warranty status of this work.
\
hex
0 value fcode-sys-table \ table with built-in fcodes (0-0x7ff)
true value ?fcode-offset16 \ fcode offsets are 16 instead of 8 bit?
1 value fcode-spread \ fcode spread (1, 2 or 4)
0 value fcode-table \ pointer to fcode table
false value ?fcode-verbose \ do verbose fcode execution?
defer _fcode-debug? \ If true, save names for FCodes with headers
true value fcode-headers? \ If true, possibly save names for FCodes.
0 value fcode-stream-start \ start address of fcode stream
0 value fcode-stream \ current fcode stream address
variable fcode-end \ state variable, if true, fcode program terminates.
defer fcode-c@ \ get byte
: fcode-push-state ( -- <state information> )
?fcode-offset16
fcode-spread
fcode-table
fcode-headers?
fcode-stream-start
fcode-stream
fcode-end @
['] fcode-c@ behavior
;
: fcode-pop-state ( <state information> -- )
to fcode-c@
fcode-end !
to fcode-stream
to fcode-stream-start
to fcode-headers?
to fcode-table
to fcode-spread
to ?fcode-offset16
;
\
\ fcode access helper functions
\
\ fcode-ptr
\ convert FCode number to pointer to xt in FCode table.
: fcode-ptr ( u16 -- *xt )
cells
fcode-table ?dup if + exit then
\ we are not parsing fcode at the moment
dup 800 cells u>= abort" User FCODE# referenced."
fcode-sys-table +
;
\ fcode>xt
\ get xt according to an FCode#
: fcode>xt ( u16 -- xt )
fcode-ptr @
;
\ fcode-num8
\ get 8bit from FCode stream, taking spread into regard.
: fcode-num8 ( -- c ) ( F: c -- )
fcode-stream
dup fcode-spread + to fcode-stream
fcode-c@
;
\ fcode-num8-signed ( -- c ) ( F: c -- )
\ get 8bit signed from FCode stream
: fcode-num8-signed
fcode-num8
dup 80 and 0> if
ff invert or
then
;
\ fcode-num16
\ get 16bit from FCode stream
: fcode-num16 ( -- num16 )
fcode-num8 fcode-num8 swap bwjoin
;
\ fcode-num16-signed ( -- c ) ( F: c -- )
\ get 16bit signed from FCode stream
: fcode-num16-signed
fcode-num16
dup 8000 and 0> if
ffff invert or
then
;
\ fcode-num32
\ get 32bit from FCode stream
: fcode-num32 ( -- num32 )
fcode-num8 fcode-num8
fcode-num8 fcode-num8
swap 2swap swap bljoin
;
\ fcode#
\ Get an FCode# from FCode stream
: fcode# ( -- fcode# )
fcode-num8
dup 1 f between if
fcode-num8 swap bwjoin
then
;
\ fcode-offset
\ get offset from FCode stream.
: fcode-offset ( -- offset )
?fcode-offset16 if
fcode-num16-signed
else
fcode-num8-signed
then
\ Display offset in verbose mode
?fcode-verbose if
dup ." (offset) " . cr
then
;
\ fcode-string
\ get a string from FCode stream, store in pocket.
: fcode-string ( -- addr len )
pocket dup
fcode-num8
dup rot c!
2dup bounds ?do
fcode-num8 i c!
loop
\ Display string in verbose mode
?fcode-verbose if
2dup ." (const) " type cr
then
;
\ fcode-header
\ retrieve FCode header from FCode stream
: fcode-header
fcode-num8
fcode-num16
fcode-num32
?fcode-verbose if
." Found FCode header:" cr rot
." Format : " u. cr swap
." Checksum : " u. cr
." Length : " u. cr
else
3drop
then
\ TODO checksum
;
\ writes currently created word as fcode# read from stream
\
: fcode! ( F:FCode# -- )
here fcode#
\ Display fcode# in verbose mode
?fcode-verbose if
dup ." (fcode#) " . cr
then
fcode-ptr !
;
\
\ 5.3.3.1 Defining new FCode functions.
\
\ instance ( -- )
\ Mark next defining word as instance specific.
\ (defined in bootstrap.fs)
\ instance-init ( wid buffer -- )
\ Copy template from specified wordlist to instance
\
: instance-init
swap
begin @ dup 0<> while
dup /n + @ instance-cfa? if \ buffer dict
2dup 2 /n* + @ + \ buffer dict dest
over 3 /n* + @ \ buffer dict dest size
2 pick 4 /n* + \ buffer dict dest size src
-rot
move
then
repeat
2drop
;
\ new-token ( F:/FCode#/ -- )
\ Create a new unnamed FCode function
: new-token
0 0 header
fcode!
;
\ named-token (F:FCode-string FCode#/ -- )
\ Create a new possibly named FCode function.
: named-token
fcode-string
_fcode-debug? not if
2drop 0 0
then
header
fcode!
;
\ external-token (F:/FCode-string FCode#/ -- )
\ Create a new named FCode function
: external-token
fcode-string header
fcode!
;
\ b(;) ( -- )
\ End an FCode colon definition.
: b(;)
['] ; execute
; immediate
\ b(:) ( -- ) ( E: ... -- ??? )
\ Defines type of new FCode function as colon definition.
: b(:)
1 , ]
;
\ b(buffer:) ( size -- ) ( E: -- a-addr )
\ Defines type of new FCode function as buffer:.
: b(buffer:)
4 , allot
reveal
;
\ b(constant) ( nl -- ) ( E: -- nl )
\ Defines type of new FCode function as constant.
: b(constant)
3 , ,
reveal
;
\ b(create) ( -- ) ( E: -- a-addr )
\ Defines type of new FCode function as create word.
: b(create)
6 ,
['] noop ,
reveal
;
\ b(defer) ( -- ) ( E: ... -- ??? )
\ Defines type of new FCode function as defer word.
: b(defer)
5 ,
['] (undefined-defer) ,
['] (semis) ,
reveal
;
\ b(field) ( offset size -- offset+size ) ( E: addr -- addr+offset )
\ Defines type of new FCode function as field.
: b(field)
6 ,
['] noop ,
reveal
over ,
+
does>
@ +
;
\ b(value) ( x -- ) (E: -- x )
\ Defines type of new FCode function as value.
: b(value)
3 , , reveal
;
\ b(variable) ( -- ) ( E: -- a-addr )
\ Defines type of new FCode function as variable.
: b(variable)
4 , 0 ,
reveal
;
\ (is-user-word) ( name-str name-len xt -- ) ( E: ... -- ??? )
\ Create a new named user interface command.
: (is-user-word)
;
\ get-token ( fcode# -- xt immediate? )
\ Convert FCode number to function execution token.
: get-token
fcode>xt dup immediate?
;
\ set-token ( xt immediate? fcode# -- )
\ Assign FCode number to existing function.
: set-token
nip \ TODO we use the xt's immediate state for now.
fcode-ptr !
;
\
\ 5.3.3.2 Literals
\
\ b(lit) ( -- n1 )
\ Numeric literal FCode. Followed by FCode-num32.
64bit? [IF]
: b(lit)
fcode-num32 32>64
state @ if
['] (lit) , ,
then
; immediate
[ELSE]
: b(lit)
fcode-num32
state @ if
['] (lit) , ,
then
; immediate
[THEN]
\ b(') ( -- xt )
\ Function literal FCode. Followed by FCode#
: b(')
fcode# fcode>xt
state @ if
['] (lit) , ,
then
; immediate
\ b(") ( -- str len )
\ String literal FCode. Followed by FCode-string.
: b(")
fcode-string
state @ if
\ only run handle-text in compile-mode,
\ otherwise we would waste a pocket.
handle-text
then
; immediate
\
\ 5.3.3.3 Controlling values and defers
\
\ behavior ( defer-xt -- contents-xt )
\ defined in bootstrap.fs
\ b(to) ( new-value -- )
\ FCode for setting values and defers. Followed by FCode#.
: b(to)
fcode# fcode>xt
1 handle-lit
['] (to)
state @ if
,
else
execute
then
; immediate
\
\ 5.3.3.4 Control flow
\
\ offset16 ( -- )
\ Makes subsequent FCode-offsets use 16-bit (not 8-bit) form.
: offset16
true to ?fcode-offset16
;
\ bbranch ( -- )
\ Unconditional branch FCode. Followed by FCode-offset.
: bbranch
fcode-offset 0< if \ if we jump backwards, we can forsee where it goes
['] dobranch ,
resolve-dest
execute-tmp-comp
else
setup-tmp-comp ['] dobranch ,
here 0
0 ,
2swap
then
; immediate
\ b?branch ( continue? -- )
\ Conditional branch FCode. Followed by FCode-offset.
: b?branch
fcode-offset 0< if \ if we jump backwards, we can forsee where it goes
['] do?branch ,
resolve-dest
execute-tmp-comp
else
setup-tmp-comp ['] do?branch ,
here 0
0 ,
then
; immediate
\ b(<mark) ( -- )
\ Target of backward branches.
: b(<mark)
setup-tmp-comp
here 1
; immediate
\ b(>resolve) ( -- )
\ Target of forward branches.
: b(>resolve)
resolve-orig
execute-tmp-comp
; immediate
\ b(loop) ( -- )
\ End FCode do..loop. Followed by FCode-offset.
: b(loop)
fcode-offset drop
postpone loop
; immediate
\ b(+loop) ( delta -- )
\ End FCode do..+loop. Followed by FCode-offset.
: b(+loop)
fcode-offset drop
postpone +loop
; immediate
\ b(do) ( limit start -- )
\ Begin FCode do..loop. Followed by FCode-offset.
: b(do)
fcode-offset drop
postpone do
; immediate
\ b(?do) ( limit start -- )
\ Begin FCode ?do..loop. Followed by FCode-offset.
: b(?do)
fcode-offset drop
postpone ?do
; immediate
\ b(leave) ( -- )
\ Exit from a do..loop.
: b(leave)
postpone leave
; immediate
\ b(case) ( sel -- sel )
\ Begin a case (multiple selection) statement.
: b(case)
postpone case
; immediate
\ b(endcase) ( sel | <nothing> -- )
\ End a case (multiple selection) statement.
: b(endcase)
postpone endcase
; immediate
\ b(of) ( sel of-val -- sel | <nothing> )
\ FCode for of in case statement. Followed by FCode-offset.
: b(of)
fcode-offset drop
postpone of
; immediate
\ b(endof) ( -- )
\ FCode for endof in case statement. Followed by FCode-offset.
: b(endof)
fcode-offset drop
postpone endof
; immediate