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2010-08-25T09:23:17
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\ ========== Copyright Header Begin ==========================================
\
\ Hypervisor Software File: spectok.fth
\
\ Copyright (c) 2006 Sun Microsystems, Inc. All Rights Reserved.
\
\ - Do no alter or remove copyright notices
\
\ - Redistribution and use of this software in source and binary forms, with
\ or without modification, are permitted provided that the following
\ conditions are met:
\
\ - Redistribution of source code must retain the above copyright notice,
\ this list of conditions and the following disclaimer.
\
\ - Redistribution in binary form must reproduce the above copyright notice,
\ this list of conditions and the following disclaimer in the
\ documentation and/or other materials provided with the distribution.
\
\ Neither the name of Sun Microsystems, Inc. or the names of contributors
\ may be used to endorse or promote products derived from this software
\ without specific prior written permission.
\
\ This software is provided "AS IS," without a warranty of any kind.
\ ALL EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES,
\ INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A
\ PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN
\ MICROSYSTEMS, INC. ("SUN") AND ITS LICENSORS SHALL NOT BE LIABLE FOR
\ ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
\ DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES. IN NO EVENT WILL SUN
\ OR ITS LICENSORS BE LIABLE FOR ANY LOST REVENUE, PROFIT OR DATA, OR
\ FOR DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE
\ DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY,
\ ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE, EVEN IF
\ SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
\
\ You acknowledge that this software is not designed, licensed or
\ intended for use in the design, construction, operation or maintenance of
\ any nuclear facility.
\
\ ========== Copyright Header End ============================================
id: @(#)spectok.fth 2.21 01/04/06
purpose: FCode compiling words, control structures, defining words
copyright: Copyright 1991-2001 Sun Microsystems, Inc. All Rights Reserved
\ Byte-code recompiler; Compiling words and defining words
defer (fcode-debug?) ' false to (fcode-debug?)
headers
: b(lit) ( -- n ) get-long l->n state @ if [compile] literal then ; immediate
: b(') ( -- acf )
next-fc-token drop state @ if compile (') token, then
; immediate
: b(") ( -- adr len )
get-bstring
state @ if compile (") ", else "temp pack count then
; immediate
: b(to) ( -- ) next-fc-token drop do-is ; immediate
headerless
: drop-offset ( -- ) get-offset drop ;
headers
: b(do) ( -- ) drop-offset [compile] do ; immediate
: b(?do) ( -- ) drop-offset [compile] ?do ; immediate
: b(loop) ( -- ) drop-offset [compile] loop ; immediate
: b(+loop) ( -- ) drop-offset [compile] +loop ; immediate
alias b(leave) leave
alias b(<mark) begin
: b(>resolve) ( [ >mark ] -- ) state @ if [compile] then then ; immediate
headerless
: get-backward-mark ( marks -- marks' backward-mark )
0 >r \ Put a sentinel value on the return stack
\ A forward mark is an address that points to a "0"
\ A backward mark is an address that points to something else
\ Move forward mark addresses to return stack
begin dup branch@ 0= while >r repeat ( <adr ) ( r: 0 >adr0 .. >adrn )
\ Restore forward marks to data stack,
\ always floating the backward address to the top of the stack
begin r> ?dup while swap repeat ( >markn .. >mark0 <mark )
;
: skip-bytes ( -- )
get-offset offset16? if 2 else 1 then - ( #bytes-to-skip )
0 ?do get-byte drop loop
;
headers
: bbranch ( [ <mark ] -- [ >mark ] )
\ New feature
state @ 0= if skip-bytes exit then
get-offset 0< if
\ The tokenizer compiles "while" as "if" (i.e. "b?branch(+)"),
\ and "repeat" as "again then" (i.e. "bbranch(-) b(>resolve)").
\ The control flow factoring of "while .. repeat" is "if but again then"
\ It's impractical to make a smart "b?branch(+)" to automatically
\ execute the "but" in the "while" case, because there is nothing
\ on the stack before a real "if" to distinguish it from a "while".
\ Therefore, we must make "bbranch(-)" smart, automatically
\ distinguishing "again" from "repeat".
\ Unfortunately, this is an insufficient basis for ANS Forth
\ control flow with multiple "while"s. We need either "but" or
\ "b(while)". However, we can fake it out by making "again" smart
\ enough to search for a backward mark underneath a bunch of
\ forward marks. This is a cheat, but I think that it is ANS Forth
\ compliant so long as CS-PICK and CS-ROLL are not available.
get-backward-mark
[compile] again
else
\ The tokenizer compiles "else" as "bbranch(+) then".
\ The control flow factoring of "else" is "ahead but then".
[compile] ahead [compile] but
then
; immediate
: b?branch ( [ <mark ] -- [ >mark ] )
\ New feature of IEEE 1275
state @ 0= if ( flag )
if get-offset drop else skip-bytes then
exit
then
get-offset 0< if ( )
\ The get-backward-mark is needed in case of the following valid
\ ANS Forth construct: BEGIN .. WHILE .. UNTIL .. THEN
get-backward-mark [compile] until
else
[compile] if
then
; immediate
\ Eaker's case statement
alias b(case) case
: b(of) ( marks -- marks ) drop-offset [compile] of ; immediate
: b(endof) ( marks -- marks+ ) drop-offset [compile] endof ; immediate
alias b(endcase) endcase
\ I don't think we should support [ ... ] inside colon definitions,
\ because they result in stuff in the code stream that must be skipped
\ if we are directly interpreting the PROM code. Also, the result of
\ interpreting the ... stuff would have to be stuck into the code
\ stream, and that's not possible with PROM code. Since we don't
\ support vocabularies, the common usage [ also <vocabulary> ] is not
\ necessary.
headerless
: b] ( -- ) state on ;
: b[ ( -- ) state off ; immediate
: get-code-adr ( -- table-entry-adr )
get-byte get-byte ( table# byte-code )
swap >token-table ( code# table-adr )
swap ta+
;
: set-acf ( table-entry-adr -- ) acf-align lastacf swap token! ;
headers
: new-token ( -- ) \ Code stream: table# byte-code#
get-code-adr ( table-entry-adr ) set-acf
; immediate
: named-token ( -- ) \ Code stream: namestring, table#, code#
\ get-code-adr must be executed before $header in order
\ to avoid splitting the dictionary if get-code-adr has to
\ allocate a token table in the dictionary.
get-bstring get-code-adr -rot ( table-entry-adr adr len )
(fcode-debug?) if $header else 2drop then
set-acf
; immediate
: external-token ( -- ) \ Code stream: namestring, table#, code#
\ get-code-adr must be executed before "header in order
\ to avoid splitting the dictionary if get-code-adr has to
\ allocate a token table in the dictionary.
get-bstring get-code-adr -rot ( table-entry-adr adr len )
$header
set-acf
; immediate
: b(:) ( -- ) colon-cf b] ; immediate
: b(;) ( -- ) compile unnest [compile] b[ ; immediate
: b(value) ( n -- ) (value) ; immediate
: b(variable) ( -- ) (variable) ; immediate
: b(defer) ( -- ) (defer) ; immediate
: b(buffer:) ( size -- ) (buffer:) ; immediate
: b(constant) ( n -- ) constant-cf , ; immediate
: b(create) ( -- ) create-cf ; immediate
: b(field) ( offset size -- offset' ) create-cf over , + does> @ + ;
\ The following will not work:
\ create jump-table ] here pad up@ [
\ Here's how to do that:
\ create jump-table ' here token, ' pad token, ' up@ token,
headers