4 * ASSEMBLY SOURCE LISTING
8 * WITH COMPILER SECURITY
9 * AND VARIABLE LENGTH NAMES
11 * Adapted by Joel Matthew Rees
12 * from fig-FORTH for 6800 by Dave Lion, et. al.
14 * This free/libre/open source publication is provided
15 * through the courtesy of:
20 * and other interested parties.
23 * P.O. Box 8231 - San Jose, CA 95155 - (408) 277-0668
24 * URL: http://www.forth.org
25 * Further distribution must include this notice.
27 NAM Copyright: FORTH Interest Group, original authors, and Joel Matthew Rees
29 * filename fig-forth-auto6809opt.asm
30 * === FORTH-6809 {date} {time}
33 * Permission is hereby granted, free of charge, to any person obtaining a copy
34 * of this software and associated documentation files (the "Software"), to deal
35 * in the Software without restriction, including without limitation the rights
36 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
37 * copies of the Software, and to permit persons to whom the Software is
38 * furnished to do so, subject to the following conditions:
40 * The above copyright notice and this permission notice shall be included in
41 * all copies or substantial portions of the Software.
43 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
44 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
45 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
46 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
47 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
48 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
51 * "Associated documentation" for this declaration of license
52 * shall be interpreted to include only the comments in this file,
53 * or, if the code is split into multiple files,
54 * all files containing the complete source.
56 * This is the MIT model license, as published by the Open Source Consortium,
57 * with associated documentation defined.
58 * It was chosen to reflect the spirit of the original
59 * terms of use, which used archaic legal terminology.
62 * Authors of the 6800 model:
63 * === Primary: Dave Lion,
67 * === The Forth Interest Group
69 * === San Carlos, CA 94070
71 * === Unbounded Computing
72 * === 1134-K Aster Ave.
73 * === Sunnyvale, CA 94086
75 NATWID EQU 2 ; bytes per natural integer/pointer
76 * The original version was developed on an AMI EVK 300 PROTO
77 * system using an ACIA for the I/O.
78 * This version is developed targeting the Tandy Color Computer.
81 * is done in three subroutines:
82 * PEMIT ( word # 182 )
86 * The FORTH words for disc related I/O follow the model
87 * of the FORTH Interest Group, but have not yet been
88 * tested using a real disc.
90 * Addresses in the 6800 implementation reflect the fact that,
91 * on the development system, it was convenient to
92 * write-protect memory at hex 1000, and leave the first
93 * 4K bytes write-enabled. As a consequence, code from
94 * location $1000 to lable ZZZZ could be put in ROM.
95 * Minor deviations from the model were made in the
96 * initialization and words ?STACK and FORGET
97 * in order to do this.
98 * Those deviations will be altered in this
99 * implementation for the 6809 -- Color Computer.
103 MEMT32 EQU $7FFF absolute end of all ram
105 MEMTOP EQU MEMT32 ; tentative guess
106 ACIAC EQU $FBCE the ACIA control address and
107 ACIAD EQU ACIAC+1 data address for PROTO
109 * MEMORY MAP for this 16K|32K system:
110 * ( delineated so that systems with 4k byte write-
111 * protected segments can write protect FORTH )
113 * addr. contents pointer init by
114 * **** ******************************* ******* ******
115 * 2nd through 4th per-user tables
117 USERSZ EQU 256 ; (Addressable by DP)
118 USER16 EQU 1 ; We can change these for ROMPACK or 64K.
121 IUP16 EQU MEMT16+1-USER16*USERSZ
122 IUP32 EQU MEMT32+1-USER32*USERSZ
125 * user tables of variables
126 * registers & pointers for the virtual machine
127 * scratch area used by various words
128 * 3F00|7C00 <== UP (DICTPT)
130 * substitute for disc mass memory
133 * 3300|7000 LO,MEMEND
134 RAMD16 EQU IUP16-RAMSCR*SCRSZ
135 RAMD32 EQU IUP32-RAMSCR*SCRSZ
141 * 4 buffer sectors of VIRTUAL MEMORY
142 NBLK EQU 4 ; # of disc buffer blocks for virtual memory
143 * Should NBLK be SCRSZ/SECTSZ?
144 * each block is SECTSZ+SECTRL bytes in size,
145 * holding SECTSZ characters
148 BUFSZ EQU (SECTSZ+SECTRL)*NBLK
150 BUFB16 EQU MEME16-BUFSZ
151 BUFB32 EQU MEME32-BUFSZ
153 * "end" of "usable ram" -- in 16K
154 * 2EE0|6BE0 <== RP RINIT
159 * (64|112 levels nesting)
163 SFTB16 EQU IRP16-RSTK16
164 SFTB32 EQU IRP32-RSTK32
167 * holds up to 256 characters
168 * and is scanned upward by IN
172 ITIB16 EQU SFTB16-TIBSZ
173 ITIB32 EQU SFTB32-TIBSZ
175 * 2D60|6A00 <== IN TIB
179 * 2D60|6A00 <== SP SP0,SINIT
181 * | grows downward from 2A60|6A00
185 * I DICTIONARY grows upward
187 * ???? end of ram-dictionary. <== DICTPT DPINIT
190 * ???? "FORTH" ( a word ) <=, <== CONTEXT
192 * start of ram-dictionary.
194 * >>>>>> memory from here up must be in RAM area <<<<<<
197 * 6k of romable "FORTH" <== IP ABORT
199 * the VIRTUAL FORTH MACHINE
201 * 1208 initialization tables
202 * 1204 <<< WARM START ENTRY >>>
203 * 1200 <<< COLD START ENTRY >>>
204 * 1200 lowest address used by FORTH
209 * >>>>>> memory from here down left alone <<<<<<
210 * >>>>>> so we can safely call ROM routines <<<<<<
216 * CONVENTIONS USED IN THIS PROGRAM ARE AS FOLLOWS :
218 * IP (hardware Y) points to the current instruction ( pre-increment mode )
219 * RP (hardware S) points to last return address pushedin return stack
220 * SP (hardware U) points to last byte pushed in data stack
222 * Y must be IP when NEXT is entered (if using the inner loop).
224 * When A and B hold one 16 bit FORTH data word,
225 * A contains the high byte, B, the low byte.
227 * UP (hardware DP) is the base of per-task ("user") variables.
228 * (Be careful of the stray semantics of "user".)
230 * W (hardware X) is the pointer to the "code field" address of native CPU
231 * machine code to be executed for the definition of the dictionary word
232 * to be executed/currently executing.
233 * The following natural integer (word) begins any "parameter section"
234 * (body) -- similar to a "this" pointer, but not the same.
235 * It may be native CPU machine code, or it may be a global variable,
236 * or it may be a list of Forth definition words (addresses).
239 * This implementation uses the native subroutine architecture
240 * rather than a postponed-push call that the 6800 model VM uses
241 * to save code and time in leaf routines.
243 * This should allow directly calling many of the Forth words
244 * from assembly language code.
245 * (Be aware of the need for a valid W in some cases.)
246 * It won't allow mixing assembly language directly into Forth word lists.
250 * 0 is false, anything else is true.
251 * Most places in this model that set a boolean flag set true as 1.
252 * This is in contrast to many models that set a boolean flag as -1.
257 * This system is shown with one user (task),
258 * but additional users (tasks) may be added
259 * by allocating additional user tables:
263 UBASEX RMB USERSZ data table for extra users
265 * Some of this stuff gets initialized during
266 * COLD start and WARM start:
267 * [ names correspond to FORTH words of similar (no X) name ]
271 * A few useful VM variables
272 * Will be removed when they are no longer needed.
273 * All are replaced by 6809 registers.
275 N RMB 10 used as scratch by (FIND),ENCLOSE,CMOVE,EMIT,KEY,
276 * SP@,SWAP,DOES>,COLD
279 * These locations are used by the TRACE routine :
281 TRLIM RMB 1 the count for tracing without user intervention
282 TRACEM RMB 1 non-zero = trace mode
283 BRKPT RMB 2 the breakpoint address at which
284 * the program will go into trace mode
285 VECT RMB 2 vector to machine code
286 * (only needed if the TRACE routine is resident)
289 * Registers used by the FORTH virtual machine:
293 W RMB 2 the instruction register points to 6800 code
294 * This is not exactly accurate. Points to the definiton body,
295 * which is native CPU machine code when it is native CPU machine code.
296 IP RMB 2 the instruction pointer points to pointer to 6800 code
297 RP RMB 2 the return stack pointer
298 UP RMB 2 the pointer to base of current user's 'USER' table
299 * ( altered during multi-tasking )
301 *UORIG RMB 6 3 reserved variables
302 RMB 6 3 reserved variables
303 XSPZER RMB 2 initial top of data stack for this user
304 XRZERO RMB 2 initial top of return stack
305 XTIB RMB 2 start of terminal input buffer
306 XWIDTH RMB 2 name field width
307 XWARN RMB 2 warning message mode (0 = no disc)
308 XFENCE RMB 2 fence for FORGET
309 XDICTP RMB 2 dictionary pointer
310 XVOCL RMB 2 vocabulary linking
311 XBLK RMB 2 disc block being accessed
312 XIN RMB 2 scan pointer into the block
313 XOUT RMB 2 cursor position
314 XSCR RMB 2 disc screen being accessed ( O=terminal )
315 XOFSET RMB 2 disc sector offset for multi-disc
316 XCONT RMB 2 last word in primary search vocabulary
317 XCURR RMB 2 last word in extensible vocabulary
318 XSTATE RMB 2 flag for 'interpret' or 'compile' modes
319 XBASE RMB 2 number base for I/O numeric conversion
320 XDPL RMB 2 decimal point place
322 XCSP RMB 2 current stack position, for compile checks
325 XDELAY RMB 2 carriage return delay count
326 XCOLUM RMB 2 carriage width
327 IOSTAT RMB 2 last acia status from write/read
338 * end of user table, start of common system variables
347 * The FORTH program ( address $1200 to about $27FF ) will be written
348 * so that it can be in a ROM, or write-protected if desired,
349 * but right now we're just getting it running.
352 * ######>> screen 3 <<
354 ***************************
355 ** C O L D E N T R Y **
356 ***************************
360 ***************************
361 ** W A R M E N T R Y **
362 ***************************
364 * JMP WENT warm-start code, keeps current dictionary intact
365 LBSR WENT warm-start code, keeps current dictionary intact
369 ******* startup parmeters **************************
371 FDB $6809,0000 cpu & revision
372 FDB 0 topmost word in FORTH vocabulary
373 * BACKSP FDB $7F backspace character for editing
374 BACKSP FDB $08 backspace character for editing
375 UPINIT FDB UORIG initial user area
376 * UPINIT FDB UORIG initial user area
377 SINIT FDB ISP ; initial top of data stack
378 * SINIT FDB ORIG-$D0 initial top of data stack
379 RINIT FDB IRP ; initial top of return stack
380 * RINIT FDB ORIG-2 initial top of return stack
381 FDB ITIB ; terminal input buffer
382 * FDB ORIG-$D0 terminal input buffer
383 FDB 31 initial name field width
384 FDB 0 initial warning mode (0 = no disc)
385 FENCIN FDB REND initial fence
386 DPINIT FDB REND cold start value for DICTPT
387 VOCINT FDB FORTH+4*NATWID
388 COLINT FDB 132 initial terminal carriage width
389 DELINT FDB 4 initial carriage return delay
390 ****************************************************
394 * ######>> screen 13 <<
395 * These were of questionable use anyway,
396 * kept here now to satisfy the assembler and show hints.
397 * They're too much trouble to use with native subroutine call anyway.
398 * PULABX PULS A ; 24 cycles until 'NEXT'
400 * PULABX PULU A,B ; ?? cycles until 'NEXT'
401 * STABX STA 0,X 16 cycles until 'NEXT'
403 * STABX STD 0,X ; ?? cycles until 'NEXT'
405 * GETX LDA 0,X 18 cycles until 'NEXT'
407 * GETX LDD 0,X ?? cycles until 'NEXT'
408 * PUSHBA PSHS B ; 8 cycles until 'NEXT'
410 * PUSHBA PSHU A,B ; ?? cycles until 'NEXT'
414 * "NEXT" takes ?? cycles if TRACE is removed,
416 * and ?? cycles if trace is present and NOT tracing.
418 * = = = = = = = t h e v i r t u a l m a c h i n e = = = = =
420 * NEXT itself might just completely go away.
421 * About the only reason to keep it is to allowing executing a list
422 * which allows a cheap TRACE routine.
424 * NEXT is a loop which implements the Forth VM.
425 * It basically cycles through calling the code out of code lists,
427 * Using a native CPU return for this uses a few extra cycles per call,
428 * compared to simply jumping to each definition and jumping back
429 * to the known beginning of the loop,
430 * but the loop itself is really only there for convenience.
432 * This implementation uses the native subroutine call,
433 * to break the wall between Forth code and non-Forth code.
436 * LEAX 1,X ; pre-increment mode
439 NEXT ; IP is Y, push before using, pull before you come back here.
441 * NEXT2 LDX 0,X get W which points to CFA of word to be done
442 NEXT2 LDX ,Y++ get W which points to CFA of word to be done
445 * But NEXT2 is too much trouble to use with subroutine threading anyway.
447 NEXT3 ; W is X until you use X for something else. (TOS points back here.)
448 * But NEXT3 is too much trouble to use with subroutine threading anyway.
449 * LDX 0,X get VECT which points to executable code
451 * The next instruction could be patched to JMP TRACE =
452 * if a TRACE routine is available: =
456 JSR [,X] ; Saving the postinc cycles,
457 * ; but X must be bumped NATWID to the parameters.
459 * JMP TRACE ( an alternate for the above )
460 BSR DBGREG ( an alternate for the above )
461 * In other words, with the call and the NOP,
462 * there is room to patch the call with a JMP to your TRACE
463 * routine, which you have to provide.
485 DBGNrt PULS CC,D,X,Y,PC
496 ADDB #$C7 ; ($40-$39)-$40
513 DBGREG PSHS U,Y,X,DP,B,A,CC
528 LDD 3*NATWID+4,S ; PC:505
535 LDD 2*NATWID+4,S ; U:50E
539 LDD 1*NATWID+4,S ; Y:513
541 LDD 0*NATWID+4,S ; X at 517
553 LDD [3*NATWID+4,S] ; PC
559 LDD [2*NATWID+4,S] ; U
563 LDD [1*NATWID+4,S] ; Y
565 LDD [0*NATWID+4,S] ; X
610 DBGRdU LDY 2*NATWID+4,S
618 DBGRrt PULS CC,A,B,DP,X,Y,U,PC
619 DBGRLB FCC 'DPCC PC S U Y X A B '
625 * = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
632 * Pushes the following natural width integer from the instruction stream
633 * as a literal, or immediate value.
638 * FDB LITERAL-TO-BE-PUSHED
641 * In native processor code, there should be a better way, use that instead.
642 * More specifically, DO NOT CALL THIS from assembly language code.
643 * (Note that there is no compile-only flag in the fig model.)
645 * See (FIND), or PFIND , for layout of the header format.
648 FCC 'LI' ; 'LIT' : NOTE: this is different from LITERAL
649 FCB $D4 ; 'T'|'\x80' ; character code for T, with high bit set.
650 FDB 0 ; link of zero to terminate dictionary scan
651 LIT FDB *+NATWID ; Note also that LIT is meaningless in native code.
663 * ######>> screen 14 <<
666 * Pushes the following byte from the instruction stream
667 * as a literal, or immediate value.
672 * FCB LITERAL-TO-BE-PUSHED
675 * If this is kept, it should have a header for TRACE to read.
676 * If the data bus is wider than a byte, you don't want to do this.
677 * Byte shaving like this is often counter-productive anyway.
678 * Changing the name to LIT8, hoping that will be more understandable.
679 * Also, see comments for LIT.
680 * (Note that there is no compile-only flag in the fig model.)
682 FCC 'LIT' ; 'LIT8' : NOTE: this is different from LITERAL
685 LIT8 FDB *+NATWID (this was an invisible word, with no header)
686 LDB ,Y+ ; This also is meaningless in native code.
698 * off is offset in video buffer area.
700 FCC 'SHOWTO' ; 'SHOWTOS'
729 * Jump to address on stack. Used by the "outer" interpreter to
730 * interactively invoke routines.
731 * Might be useful to have EXECUTE test the pointer, as done in BIF-6809.
733 FCC 'EXECUT' ; 'EXECUTE'
737 PULU X ; Gotta have W anyway, just in case.
738 JMP [,X] ; Tail return.
740 * LDX 0,X get code field address (CFA)
741 * LEAS 1,S ; pop stack
745 * ######>> screen 15 <<
748 * Add the following word from the instruction stream to the
749 * instruction pointer (Y++). Causes a program branch in Forth code stream.
751 * In native processor code, there should be a better way, use that instead.
752 * More specifically, DO NOT CALL THIS from assembly language code.
753 * This is only for Forth code stream.
754 * Also, see comments for LIT.
756 FCC 'BRANC' ; 'BRANCH'
759 BRAN FDB ZBYES ; Go steal code in ZBRANCH
761 * Moving code around to optimize the branch taking case in 0BRANCH.
762 ZBNO LEAY NATWID,Y ; No branch.
766 * BRANCH if flag is zero.
768 * In native processor code, there should be a better way, use that instead.
769 * More specifically, DO NOT CALL THIS from assembly language code.
770 * This is only for Forth code stream.
771 * Also, see comments for LIT.
773 FCC '0BRANC' ; '0BRANCH'
780 LEAY D,Y ; IP is postinc
784 * PSHS B ; ** emulating ABA:
788 * ZBYES LDX IP Note: code is shared with BRANCH, (+LOOP), (LOOP)
796 * ZBNO LDX IP no branch. This code is shared with (+LOOP), (LOOP).
797 * LEAX 1,X ; jump over branch delta
802 * ######>> screen 16 <<
804 * ( --- ) ( limit index *** limit index+1) C
805 * ( limit index *** )
806 * Counting loop primitive. The counter and limit are the top two
807 * words on the return stack. If the updated index/counter does
808 * not exceed the limit, a branch occurs. If it does, the branch
809 * does not occur, and the index and limit are dropped from the
812 * In native processor code, there should be a better way, use that instead.
813 * More specifically, DO NOT CALL THIS from assembly language code.
814 * This is only for Forth code stream.
815 * Also, see comments for LIT.
817 FCC '(LOOP' ; '(LOOP)'
821 LDD #1 ; Borrowing from BIF-6809.
822 XLOOPA ADDD NATWID,S ; Dodge the return address.
827 LDX ,S ; synthetic return
828 LEAS 3*NATWID,S ; Clean up the index and limit.
831 * LDB #1 get set to increment counter by 1 (Clears N.)
832 * BRA XPLOP2 go steal other guy's code!
835 * ( n --- ) ( limit index *** limit index+n ) C
836 * ( limit index *** )
837 * Loop with a variable increment. Terminates when the index
838 * crosses the boundary from one below the limit to the limit. A
839 * positive n will cause termination if the result index equals the
840 * limit. A negative n must cause the index to become less than
841 * the limit to cause loop termination.
843 * Note that the end conditions are not symmetric around zero.
845 * In native processor code, there should be a better way, use that instead.
846 * More specifically, DO NOT CALL THIS from assembly language code.
847 * This is only for Forth code stream.
848 * Also, see comments for LIT.
850 FCC '(+LOOP' ; '(+LOOP)'
853 XPLOOP FDB *+NATWID ; Borrowing from BIF-6809.
855 BPL XLOOPA ; Steal plain loop code for forward count.
856 ADDD NATWID,S ; Dodge the return address
860 BRA XLOOPN ; This path is less time-sensitive.
862 * This should work, but I want to use tested code.
863 * PULU A,B ; Get the increment.
864 * XPLOP2 PULS X ; Pre-clear the return stack.
865 * PSHU A ; Save the direction in high bit.
868 * SUBD NATWID,S ; Check limit.
870 ** I think this should work:
871 * EORA ,U+ ; dir < 0 and (count - limit) >= 0
872 * BPL XPLONO ; or dir >= 0 and (count - limit) < 0
874 * LEAY D,Y ; IP is postinc
876 * XPLONO LEAS 2*NATWID,S
877 * JMP ,X ; synthetic return
879 * This definitely should work:
880 * TST ,U+ ; Get the sign
885 * LEAY D,Y ; IP is postinc
887 * XPLOF CMPD NATWID,S
889 * XPLONO LEAS 2*NATWID,S
890 * JMP ,X ; synthetic return
892 * 6800 Probably could have used the exclusive-or method, too.:
893 * PULS A ; get increment
896 * BPL XPLOF forward looping
902 * BRA XPLONO fall through
906 * ADDB 3,X add it to counter
908 * STB 3,X store new counter value
917 * XPLONO LEAX 1,X ; done, don't branch back
922 * BRA ZBNO use ZBRAN to skip over unused delta
924 * ######>> screen 17 <<
926 * ( limit index --- ) ( *** limit index )
927 * Move the loop parameters to the return stack. Synonym for D>R.
932 XDO FDB *+NATWID This is the RUNTIME DO, not the COMPILING DO
933 LDX ,S ; Save the return address.
936 PULU A,B ; Maintain order.
938 JMP ,X ; synthetic return
957 * ( --- index ) ( limit index *** limit index )
958 * Copy the loop index from the return stack. Synonym for R.
963 LDD NATWID,S ; Dodge return address.
971 * ######>> screen 18 <<
973 * ( c base --- false )
974 * ( c base --- n true )
975 * Translate C in base, yielding a translation valid flag. If the
976 * translation is not valid in the specified base, only the false
982 DIGIT FDB *+NATWID NOTE: legal input range is 0-9, A-Z
983 LDD NATWID,U ; Check the whole thing.
984 SUBD #$30 ; ascii zero
985 BMI DIGIT2 IF LESS THAN '0', ILLEGAL
987 BMI DIGIT0 IF '9' OR LESS
989 BMI DIGIT2 if less than 'A'
991 BPL DIGIT2 if greater than 'Z'
992 SUBD #7 translate 'A' thru 'F'
993 DIGIT0 CMPD ,U ; Check the base.
994 BPL DIGIT2 if not less than the base
995 STD NATWID,U ; Store converted digit. (High byte known zero.)
996 LDD #1 ; set valid flag
997 DIGIT1 STD ,U ; store the flag
999 DIGIT2 LDD #0 ; set not valid flag
1000 LEAU NATWID,U ; pop base
1004 * SUBA #$30 ascii zero
1005 * BMI DIGIT2 IF LESS THAN '0', ILLEGAL
1007 * BMI DIGIT0 IF '9' OR LESS
1009 * BMI DIGIT2 if less than 'A'
1011 * BPL DIGIT2 if greater than 'Z'
1012 * SUBA #7 translate 'A' thru 'F'
1014 * BPL DIGIT2 if not less than the base
1016 * STA 3,X store digit
1017 * DIGIT1 STB 1,X store the flag
1021 * LEAS 1,S ; pop bottom number
1023 * STB 0,X make sure both bytes are 00
1026 * ######>> screen 19 <<
1028 * The word definition format in the dictionary:
1030 * (Symbol names are bracketed by bytes with the high bit set, rather than linked.)
1032 * NFA (name field address):
1033 * char-count + $80 Length of symbol name, flagged with high bit set.
1034 * char 1 Characters of symbol name.
1037 * char n + $80 symbol termination flag (char set < 128 code points)
1038 * LFA (link field address):
1039 * link high byte \___pointer to previous word in list
1040 * link low byte / -- Combined allocation/dictionary list. --
1041 * CFA (code field address):
1042 * CFA high byte \___pointer to native CPU machine code
1043 * CFA low byte / -- Consider this the characteristic code. --
1044 * PFA (parameter field address):
1045 * parameter fields -- Machine code for low-level native machine CPU code,
1046 * " instruction list for high-level Forth code,
1047 * " constant data for constants, pointers to per task variables,
1048 * " space for variables, for global variables, etc.
1050 * In the case of native CPU machine code, the address at CFA will be PFA.
1052 * Definition attributes:
1053 FIMMED EQU $40 ; Immediate word flag.
1054 FSMUDG EQU $20 ; Smudged => definition not ready.
1055 CTMASK EQU ($FF&(^($80|FIMMED))) ; For unmasking the length byte.
1056 * Note that the SMUDGE bit is not masked out.
1058 * But we really want more (Thinking for a new model, need one more byte):
1059 * FCOMPI EQU $10 ; Compile-time-only.
1060 * FASSEM EQU $08 ; Assembly-language code only.
1061 * F4THLV EQU $04 ; Must not be called from assembly language code.
1062 * These would require some significant adjustments to the model.
1063 * We also want to put the low-level VM stuff in its own vocabulary.
1066 * (FIND) ( name vocptr --- locptr length true )
1067 * ( name vocptr --- false )
1068 * Search vocabulary for a symbol called name.
1069 * name is a pointer to a high-bit bracket string with length head.
1070 * vocptr is a pointer to the NFA of the tail-end (LATEST) definition
1071 * in the vocabulary to be searched.
1072 * Hidden (SMUDGEd) definitions are lexically not equal to their name strings.
1074 FCC '(FIND' ; '(FIND)'
1078 PSHS Y ; Have to track two pointers.
1079 * Use the stack and registers instead of temp area N.
1080 PA0 EQU NATWID ; pointer to the length byte of name being searched against
1081 PD EQU 0 ; pointer to NFA of dict word being checked
1085 LDX PD,U ; Start in on the vocabulary (NFA).
1086 PFNDLP LDY PA0,U ; Point to the name to check against.
1087 LDB ,X+ ; get dict name length byte
1088 TFR B,A ; Save it in case it matches.
1091 CMPB ,Y+ ; Compare lengths
1095 TSTB ; ; Is high bit of character in dictionary entry set?
1099 ANDB #$7F ; Clear high bit from dictionary.
1100 CMPB ,Y+ ; Compare "last" characters.
1102 BEQ FOUND ; Matches even if dictionary actual length is shorter.
1103 PFNDLN LDX ,X++ ; Get previous link in vocabulary.
1105 BNE PFNDLP ; Continue if link not=0
1108 LEAU NATWID,U ; Return only false flag.
1115 PFNDCH CMPB ,Y+ ; Compare characters.
1119 PFNDSC LDB ,X+ ; scan forward to end of this name in dictionary
1127 FOUND LEAX 2*NATWID,X
1141 * NOP ; Probably leftovers from a debugging session.
1143 * PD EQU N ptr to dict word being checked
1149 * PFIND0 PULS A ; loop to get arguments
1156 * PFNDLP LDB 0,X get count dict count
1162 * LDA 0,X get count from arg
1164 * STX PA intialize PA
1165 * PSHS B ; ** emulating CBA:
1166 * CMPA ,S+ ; compare lengths
1176 * TSTB ; is dict entry neg. ?
1178 * ANDB #$7F clear sign
1179 * PSHS B ; ** emulating CBA:
1182 * PFNDLN LDX 0,X get new link
1183 * BNE PFNDLP continue if link not=0
1190 * PFNDCH PSHS B ; ** emulating CBA:
1194 * PFNDSC LDB 0,X scan forward to end of this name
1201 * FOUND LDA PD compute CFA
1214 * PSHS A ; Left over from a stray copy-paste, I guess.
1220 * ######>> screen 20 <<
1222 * ( buffer ch --- buffer symboloffset delimiteroffset scancount )
1223 * ( buffer ch --- buffer symboloffset nuloffset scancount ) ( Scan count == nuloffset )
1224 * ( buffer ch --- buffer nuloffset onepast scancount )
1225 * Scan buffer for a symbol delimited by ch or ASCII NUL,
1226 * return the length of the buffer region scanned,
1227 * the offset to the trailing delimiter,
1228 * and the offset of the first character of the symbol.
1229 * Leave the buffer on the stack.
1230 * Scancount is also offset to first character not yet looked at.
1231 * If no symbol in buffer, scancount and symboloffset point to NUL
1232 * and delimiteroffset points one beyond for some reason.
1233 * On trailing NUL, delimiteroffset == scancount.
1234 * (Buffer is the address of the buffer array to scan.)
1235 * (This is a bit too tricky, really.)
1237 FCC 'ENCLOS' ; 'ENCLOSE'
1241 LDA 1,U ; Delimiter character to match against in A.
1242 LDX NATWID,U ; Buffer to scan in.
1243 CLRB ; Initialize offset. (Buffer < 256 wide!)
1244 * Scan to a non-delimiter or a NUL
1245 ENCDEL TST B,X ; NUL ?
1247 CMPA B,X ; Delimiter?
1249 INCB ; count character
1251 * Found first character. Save the offset.
1252 ENC1ST STB 1,U ; Found first non-delimiter character --
1253 CLR ,U ; store the count, zero high byte.
1254 * Scan to a delimiter or a NUL
1255 ENCSYM TST B,X ; NUL ?
1257 CMPA B,X ; delimiter?
1261 * Found end of symbol. Push offset to delimiter found.
1262 ENCEND CLRA ; high byte -- buffer < 255 wide!
1263 PSHU A,B ; Offset to seen delimiter.
1264 * Advance and push address of next character to check.
1265 ADDD #1 ; In case offset was 255.
1268 * Found NUL before non-delimiter, therefore there is no word
1269 ENCNUL CLRA ; high byte -- buffer < 255 wide!
1270 STD ,U ; offset to NUL.
1271 ADDD #1 ; Point after NUL to allow (FIND) to match it.
1273 SUBD #1 ; Next is not passed NUL.
1274 PSHU A,B ; Stealing code will save only one byte.
1276 * Found NUL following the word instead of delimiter.
1281 PSHU A,B ; Save offset to first after symbol (NUL)
1283 PSHU A,B ; and count scanned.
1288 * FC means offset (bytes) to First Character of next word
1289 * EW " " to End of Word
1290 * NC " " to Next Character to start next enclose at
1291 * ENCLOS FDB *+NATWID
1293 * PULS B ; now, get the low byte, for an 8-bit delimiter
1297 * * wait for a non-delimiter or a NUL
1300 * PSHS B ; ** emulating CBA:
1301 * CMPA ,S+ ; CHECK FOR DELIM
1306 * * found first character. Push FC
1307 * ENC1ST LDA N found first char.
1311 * wait for a delimiter or a NUL
1314 * PSHS B ; ** emulating CBA:
1315 * CMPA ,S+ ; ckech for delim.
1320 * * found EW. Push it
1325 * * advance and push NC
1328 * found NUL before non-delimiter, therefore there is no word
1329 * ENCNUL LDB N found NUL
1333 * BRA ENC0TR+2 ; ********** POTENTIAL BUG HERE *******
1334 * ******** Should use labels in case opcodes change! ********
1335 * found NUL following the word instead of SPACE
1339 * ENCL8 LDB N save NC
1344 * ######>> screen 21 <<
1345 * The next 4 words call system dependant I/O routines
1346 * which are listed after word "-->" ( lable: "arrow" )
1347 * in the dictionary.
1351 * Write c to the output device (screen or printer).
1352 * ROM Uses the ECB device number at address $6F,
1353 * -2 is printer, 0 is screen.
1360 LBSR PEMIT ; PEMIT expects the character in D.
1369 * INC XOUT+1-UORIG,X
1371 * ****WARNING**** HARD OFFSET: *+4 ****
1378 * Wait for a key from the keyboard.
1379 * If the key is BREAK, set the high byte (result $FF03).
1385 LBSR PKEY ; PKEY leaves the key/break code in D.
1396 * Scan keyboard, but do not wait.
1397 * Return 0 if no key,
1398 * BREAK ($ff03) if BREAK is pressed,
1399 * or key currently pressed.
1401 FCC '?TERMINA' ; '?TERMINAL'
1405 LBSR PQTER ; PQTER leaves the flag/key in D.
1410 * JMP PUSHBA stack the flag
1414 * EMIT a Carriage Return (ASCII CR).
1420 LBRA PCR ; Nothing really to do here.
1424 * ######>> screen 22 <<
1426 * ( source target count --- )
1427 * Copy/move count bytes from source to target.
1428 * Moves ascending addresses,
1429 * so that overlapping only works if the source is above the destination.
1431 FCC 'CMOV' ; 'CMOVE' : source, destination, count
1454 * One way: ; takes ( 37+17*count+9*(count/256) cycles )
1455 * PSHS Y ; #2~7 ; Gotta have our pointers.
1458 * PULU D,X,Y ; #2~11
1459 * PSHS A ; #2~6 ; Gotta have our pointers.
1472 * PULS A,Y,PC ; #2~10
1473 * Another way ; takes ( 42+17*count+9*(count/256) cycles )
1475 * SUBD ,U++ ; #2~9 ; invert the count
1487 * PULS A,Y,PC ; #2~10
1488 * Yet another way ; takes ( 37+29*count cycles )
1490 * LDX NATWID,U ; #2~6
1491 * LDY NATWID,U ; #3~7
1501 * LEAU 3*NATWID,U ; #2~5
1503 * Yet another way ; takes ( 44+24*odd+33*count/2 cycles )
1505 * LDX NATWID,U ; #2~6
1506 * LDY 2*NATWID,U ; #3~7
1524 * LEAU 3*NATWID,U ; #2~5
1526 * From the 6800 model:
1527 * CMOVE FDB *+2 takes ( 43+47*count cycles ) on 6800
1531 * STA 0,X move parameters to scratch area
1553 * ######>> screen 23 <<
1556 * Multiplies the top two unsigned integers,
1557 * yielding a double integer product.
1564 LDA 2*NATWID+1,U ; least
1568 LDA 2*NATWID,U ; most
1572 LDD 2*NATWID+1,U ; first inner (u2 lo, u1 hi)
1578 LDA 2*NATWID,U ; second inner (u2 hi)
1579 LDB 3*NATWID,U ; (u1 lo)
1596 * The following is a subroutine which
1597 * multiplies top 2 words on stack,
1598 * leaving 32-bit result: high order word in A,B
1599 * low order word in 2nd word of stack.
1601 * USTARS LDA #16 bits/word counter
1606 * USTAR2 ROR 5,X shift multiplier
1614 * RORB ; shift result
1616 * USTAR4 LEAS 1,S ; dump counter
1619 * ######>> screen 24 <<
1621 * ( ud u --- uremainder uquotient )
1622 * Divides the top unsigned integer
1623 * into the second and third words on the stack
1624 * as a single unsigned double integer,
1625 * leaving the remainder and quotient (quotient on top)
1626 * as unsigned integers.
1628 * The smaller the divisor, the more likely dropping the high word
1629 * of the quotient loses significant bits. See M/MOD .
1638 LDD NATWID,U ; dividend
1639 USLDIV CMPD ,U ; divisor
1641 ANDCC #~1 ; carry clear
1644 ORCC #1 ; quotient, (carry set)
1645 USLBIT ROL 2*NATWID+1,U ; save it
1657 PULS A,PC ; Avoiding a LEAS 1,S by discarding A.
1670 * USL2 ANDCC #~$01 ; CLC :
1688 * JMP SWAP+4 reverse quotient & remainder
1690 * ######>> screen 25 <<
1693 * Bitwise and the top two integers.
1713 * Bitwise or the top two integers.
1733 * Bitwise exclusive or the top two integers.
1751 * ######>> screen 26 <<
1754 * Fetch the parameter stack pointer (before it is pushed).
1755 * This points at whatever was on the top of stack before.
1765 * STX N scratch area
1770 * ( whatever --- nothing )
1771 * Initialize the parameter stack pointer from the USER variable S0.
1772 * Effectively clears the stack.
1781 * LDX XSPZER-UORIG,X
1782 * TFR X,S ; TXS : watch it ! X and S are not equal on 6800.
1785 * ( whatever *** nothing )
1786 * Initialize the return stack pointer from the initialization table
1787 * instead of the user variable R0, for some reason.
1788 * Quite possibly, this should be from R0.
1789 * Effectively aborts all in process definitions, except the active one.
1790 * An emergency measure, to be sure.
1791 * The routine that calls this must never execute a return.
1792 * So this should never be executed from the terminal, I guess.
1793 * This is another that should be compile-time only, and in a separate vocabulary.
1799 PULS X ; But this guy has to return to his caller.
1802 * LDX RINIT initialize from rom constant
1808 * Pop IP from return stack (return from high-level definition).
1809 * Can be used in a screen to force interpretion to terminate.
1810 * Must not be executed when temporaries are saved on top of the return stack.
1816 PULS D,Y ; return address in D, and saved IP in Y.
1817 TFR D,PC ; Synthetic return.
1824 * LDX 0,X get address we have just finished.
1825 * JMP NEXT+2 increment the return address & do next word
1827 * ######>> screen 27 <<
1829 * ( limit index *** index index )
1830 * Force the terminating condition for the innermost loop by
1831 * copying its index to its limit.
1832 * Termination is postponed until the next
1833 * LOOP or +LOOP instruction is executed.
1834 * The index remains available for use until
1835 * the LOOP or +LOOP instruction is encountered.
1836 * Note that the assumption is that the current count is the correct count
1837 * to end at, rather than pushing the count to the final count.
1839 FCC 'LEAV' ; 'LEAVE'
1843 LDD NATWID,S ; Dodge the return address.
1856 * Move top of parameter stack to top of return stack.
1864 STD ,S ; Put it where the return address was.
1879 * Move top of return stack to top of parameter stack.
1899 * Copy the top of return stack to top of parameter stack.
1911 * ######>> screen 28 <<
1914 * Logically invert top of stack;
1915 * or flag true if top is zero, otherwise false.
1933 *ZEQU2 TFR S,X ; TSX :
1938 * Flag true if top is negative (MSbit set), otherwise false.
1951 * LDA #$80 check the sign bit
1960 * ######>> screen 29 <<
1962 * ( n1 n2 --- n1+n2 )
1963 * Add top two words.
1980 * ( d1 d2 --- d1+d2 )
1981 * Add top two double integers.
1997 * ANDCC #~$01 ; CLC :
2013 * Negate (two's complement) top of stack.
2015 FCC 'MINU' ; 'MINUS'
2024 * from 6800 model code:
2035 * Negate (two's complement) top two words on stack as a double integer.
2037 FCC 'DMINU' ; 'DMINUS'
2042 SUBD NATWID,U ; #2~7
2062 * ######>> screen 30 <<
2064 * ( n1 n2 --- n1 n2 n1 )
2065 * Push a copy of the second word on stack.
2081 * Discard the top word on stack.
2094 * ( n1 n2 --- n2 n1 )
2095 * Swap the top two words on stack.
2119 * Push a copy of the top word on stack.
2134 * ######>> screen 31 <<
2137 * Add the second word on stack to the word at the adr on top of stack.
2152 * PULS A ; get stack data
2154 * ADDB 1,X add & store low byte
2156 * ADCA 0,X add & store hi byte
2162 * Exclusive or byte at adr with low byte of top word.
2164 FCC 'TOGGL' ; 'TOGGLE'
2172 * Using the model code would be less likely to introduce bugs,
2173 * but that would sort-of defeat my purposes here.
2174 * Anyway, I can borrow from theoretically known good bif-6809 code
2175 * and it's fewer bytes and much faster code this way.
2177 * FDB DOCOL,OVER,CAT,XOR,SWAP,CSTORE
2180 * ######>> screen 32 <<
2183 * Replace address on stack with the word at the address.
2192 * LDX 0,X get address
2199 * Replace address on top of stack with the byte at the address.
2200 * High byte of result is clear.
2222 * Store second word on stack at address on top of stack.
2232 * LDX 0,X get address
2239 * Store low byte of second word on stack at address on top of stack.
2240 * High byte is ignored.
2251 * LDX 0,X get address
2260 * ######>> screen 33 <<
2263 * { : name sundry-activities ; } typical input
2264 * If executing (not compiling),
2265 * record the data stack mark in CSP,
2266 * Set the CONTEXT vocabulary to CURRENT,
2268 * set state to compile,
2269 * and compile the call to the trailing native CPU machine code DOCOL.
2271 * This would not be hard to flatten to native code.
2272 * But that's not the purpose of a model.
2276 COLON FDB DOCOL,QEXEC,SCSP,CURENT,AT,CONTXT,STORE
2280 * Here is the IP pusher for allowing
2281 * nested words in the virtual machine:
2282 * ( ;S is the equivalent un-nester )
2285 * Characteristic of a colon (:) definition.
2286 * Begins execution of a high-level definition,
2287 * i. e., nests the definition and begins processing icodes.
2288 * Mechanically, it pushes the IP (Y register)
2289 * and loads the Parameter Field Address of the definition which
2290 * called it into the IP.
2291 DOCOL LDD ,S ; Save the return address.
2292 STY ,S ; Nest the old IP.
2293 LEAY NATWID,X ; W still in X, bump to parameters, load as new IP.
2294 TFR D,PC ; synthetic return to interpret.
2296 * DOCOL LDX RP make room in the stack
2302 * STA 2,X Store address of the high level word
2303 * STB 3,X that we are starting to execute
2304 * LDX W Get first sub-word of that definition
2305 * JMP NEXT+2 and execute it
2309 * { : name sundry-activities ; } typical input
2310 * ERROR check data stack against mark in CSP,
2312 * unSMUDGE LATEST definition,
2313 * and set state to interpretation.
2314 FCB $C1 ; imnediate code
2317 SEMI FDB DOCOL,QCSP,COMPIL,SEMIS,SMUDGE,LBRAK
2320 * ######>> screen 34 <<
2323 * { value CONSTANT name } typical input
2326 * compile the constant value,
2327 * and compile the call to the trailing native CPU machine code DOCON.
2329 FCC 'CONSTAN' ; 'CONSTANT'
2332 CON FDB DOCOL,CREATE,SMUDGE,COMMA,PSCODE
2334 * Characteristic of a CONSTANT.
2335 * A CONSTANT simply loads its value from its parameter field
2336 * and pushes it on the stack.
2337 DOCON LDD NATWID,X ; Get the first natural width word of the parameter field.
2342 * LDB 3,X A & B now contain the constant
2345 * Not in model, needed for abstraction:
2347 * The byte width of objects on stack.
2349 FCC 'NATWI' ; 'NATWID'
2355 * Not in model, needed for abstraction:
2356 * Note that this is not defined as an INCREMENTER!
2357 * Coded to increment by the exact constant returned by NATWID
2358 * ( n --- n+NATWID )
2365 ADDD NATWCV,PCR ; Looking ahead, does not have to be PCRelative.
2368 * How this might have been done for 6800 model:
2369 * CLRA ; We know the natural width is less than 255, LOL.
2378 * { init VARIABLE name } typical input
2379 * Use CONSTANT to CREATE a header and compile the initial value, init,
2380 * then overwrite the characteristic to point to DOVAR.
2382 FCC 'VARIABL' ; 'VARIABLE'
2385 VAR FDB DOCOL,CON,PSCODE
2387 * Characteristic of a VARIABLE.
2388 * A VARIABLE pushes its PFA address on the stack.
2389 * The parameter field of a VARIABLE is the actual allocation of the variable,
2390 * so that pushing its address allows its contents to be @ed (fetched).
2391 * Ordinary arrays and strings that do not subscript themselves
2392 * may be allocated by defining a variable
2393 * and immediately ALLOTting the remaining needed space.
2394 * VARIABLES are global to all users,
2395 * and thus should be hidden in resource monitors, but aren't.
2396 DOVAR LEAX NATWID,X ; Point to the first natural width word of the parameters.
2402 * ADCA #0 A,B now contain the address of the variable
2407 * { uboffset USER name } typical input
2408 * CREATE a header and compile the unsigned byte offset in the per-USER table,
2409 * then overwrite the header with a call to DOUSER.
2410 * The USER is entirely responsible for maintaining allocation!
2415 USER FDB DOCOL,CON,PSCODE
2417 * Characteristic of a per-USER variable.
2418 * USER variables are similiar to VARIABLEs,
2419 * but are allocated (by hand!) in the per-user table.
2420 * A USER variable's parameter field contains its offset in the per-user table.
2421 DOUSER TFR DP,A ; Make a pointer to the direct page.
2423 * See Alternative -- alternatives start from this point.
2424 ADDD NATWID,X ; Add it to the offset to the per-user variable.
2426 TFR D,X ; Cache the pointer in X for the caller.
2428 * Hey, the per-user table could actually be larger than 256 bytes!
2429 * But we knew that. It's just not as esthetic to calculate it this way.
2431 * LDX NATWID,X ; Keep the offset
2432 * EXG D,X ; Prepare for EA
2437 * PSHS Y ; Get Y free for calculations.
2438 * TFR D,Y ; Y points to the UP base
2439 * LDD NATWID,X ; Get the offset
2440 * LEAX D,Y ; Leave the pointer cached in X.
2444 * From the 6800 model:
2445 * DOUSER LDX W get offset into user's table
2448 * ADDB UP+1 add to users base address
2450 * JMP PUSHBA push address of user's variable
2452 * ######>> screen 35 <<
2487 * ASCII SPACE character
2492 BL FDB DOCON ascii blank
2496 * This really shouldn't be a CONSTANT.
2498 * The base of the disk buffer space.
2500 FCC 'FIRS' ; 'FIRST'
2505 * FDB MEMEND-528 (132 * NBLK)
2508 * This really shouldn't be a CONSTANT.
2510 * The limit of the disk buffer space.
2512 FCC 'LIMI' ; 'LIMIT' : ( the end of memory +1 )
2517 * In 6800 model, was
2521 * ( --- sectorsize )
2522 * The size, in bytes, of a buffer.
2524 FCC 'B/BU' ; 'B/BUF' : (bytes/buffer)
2529 * Hardcoded in 6800 model:
2533 * ( --- blocksperscreen )
2534 * The size, in blocks, of a screen.
2535 * Should this be the same as NBLK, the number of block buffers maintained?
2537 FCC 'B/SC' ; 'B/SCR' : (blocks/screen)
2542 * Hardcoded in 6800 model as:
2544 * blocks/screen = 1024 / "B/BUF" = 8, if sectors are 128 bytes.
2548 * Calculate the address of entry (#n/2) in the boot-up parameter table.
2549 * (Adds the base of the boot-up table to n.)
2551 FCC '+ORIGI' ; '+ORIGIN'
2554 PORIG FDB DOCOL,LIT,ORIG,PLUS
2557 * ######>> screen 36 <<
2560 * This is the per-task variable recording the initial parameter stack pointer.
2570 * This is the per-task variable recording the initial return stack pointer.
2580 * Terminal Input Buffer address.
2581 * Note that this is a variable, so users may allocate their own buffers, but it must be @ed.
2590 * ( --- maxnamewidth )
2591 * This is the maximum width to which symbol names will be recorded.
2593 FCC 'WIDT' ; 'WIDTH'
2601 * Availability of error messages on disk.
2602 * Contains 1 if messages available,
2604 * -1 if a disk error has occurred.
2606 FCC 'WARNIN' ; 'WARNING'
2614 * Boundary for FORGET.
2616 FCC 'FENC' ; 'FENCE'
2624 * Dictionary pointer, fetched by HERE.
2626 FCC 'D' ; 'DP' : points to first free byte at end of dictionary
2633 * ( --- vadr ) ******* Need to check what this is!
2634 * Used in maintaining vocabularies.
2635 * I think it points to the "parent" vocabulary, but I'm not sure.
2636 * Or maybe this is the CONTEXT vocabulary. I'll have to come back here. *****
2638 FCC 'VOC-LIN' ; 'VOC-LINK'
2646 * Disk block being interpreted.
2647 * Zero refers to terminal.
2648 * ******** Should be made a 32 bit user variable! ********
2649 * But the base system needs to have full 32 bit support, div and mul, etc.
2650 * before we can do that.
2660 * Input buffer offset/cursor.
2662 FCC 'I' ; 'IN' : scan pointer for input line buffer
2670 * Output buffer offset/cursor.
2680 * Screen currently being edited, once we have an editor running.
2687 * ######>> screen 37 <<
2691 * Sector offset for LOADing screens,
2692 * set by DRIVE to make a new drive the default.
2693 * This should also be 32 bit or bigger.
2695 FCC 'OFFSE' ; 'OFFSET'
2703 * Current context of interpretation (vocabulary root).
2705 FCC 'CONTEX' ; 'CONTEXT' : points to pointer to vocab to search first
2713 * Current context of definition (vocabulary root).
2715 FCC 'CURREN' ; 'CURRENT' : points to ptr. to vocab being extended
2723 * Compiler/interpreter state.
2725 FCC 'STAT' ; 'STATE' : 1 if compiling, 0 if not
2733 * Numeric conversion base.
2735 FCC 'BAS' ; 'BASE' : number base for all input & output
2743 * Decimal point location for output.
2753 * Field width for I/O formatting.
2763 * Compiler stack mark for stack check.
2773 * Editing cursor location.
2783 * Pointer to last HELD character in PAD.
2791 * ======>> 82.5 <<== SPECIAL
2793 * Line width of active terminal.
2795 FCC 'COLUMN' ; 'COLUMNS' : line width of terminal
2801 * ######>> screen 38 <<
2803 ** An INCREMENTER probably should not be defined without a defined CONSTANT?
2805 ** Make an INCREMENTER compiling word (not in model):
2807 ** { n INCREMENTER name } typical input
2808 ** CREATE a header and compile the increment constant,
2809 ** then overwrite the header with a call to DOINC.
2811 * FCC 'INCREMENTE' ; 'INCREMENTER'
2814 * INCR FDB DOCOL,CON,PSCODE
2816 ** Characteristic of an INCREMENTER.
2817 ** This is too naive:
2819 * ADDD NATWID,X ; Add the increment.
2822 * Compiling word should check that it is compiling a CONSTANT.
2830 * Using the model keeps things semantically connected for other processors:
2831 ONEP FDB DOCOL,ONE,PLUS
2833 ** Greedy alternative:
2839 * Naive alternative:
2842 * Naive alternative:
2845 * ADDD #1 ; It's hard to imagine 1+ being other than 1.
2855 * Using the model keeps things semantically connected for other processors:
2856 TWOP FDB DOCOL,TWO,PLUS
2858 ** Greedy alternative:
2861 * ADDD TWOV,PCR ; See NAT+ (NATP)
2864 * Naive alternative:
2867 * Naive alternative:
2870 * ADDD #2 ; See NAT+ (NATP)
2876 * Get the DICTPT allocation, like a USER constant.
2877 * Should check the stack and heap for collision.
2882 HERE FDB DOCOL,DICTPT,AT
2887 * Increase/decrease heap (add n to DP),
2888 * Should ERROR check stack/heap.
2890 FCC 'ALLO' ; 'ALLOT'
2893 ALLOT FDB DOCOL,DICTPT,PSTORE
2898 * Store word n at DP++,
2899 * Should ERROR check stack/heap.
2903 COMMA FDB DOCOL,HERE,STORE,NATWC,ALLOT
2905 * COMMA FDB DOCOL,HERE,STORE,TWO,ALLOT
2910 * Store byte b at DP+,
2911 * Should ERROR check stack/heap.
2916 CCOMM FDB DOCOL,HERE,CSTORE,ONE,ALLOT
2920 * ( n1 n2 --- n1-n2 )
2921 * Subtract top two words.
2930 * SUB FDB DOCOL,MINUS,PLUS
2931 * FDB SEMIS ; Costs 6 bytes and lots of cycles.
2934 * ( n1 n2 --- n1==n2 )
2935 * Return flag true if n1 and n2 are equal, otherwise false.
2939 EQUAL FDB DOCOL,SUB,ZEQU
2943 * ( n1 n2 --- n1<n2 )
2944 * Return flag true if n1 is less than n2, otherwise false.
2965 * CMPB 1,X ; Why not sub, sbc, bge?
2975 * ( n1 n2 --- n1>n2 )
2976 * Return flag true if n1 is greater than n2, false otherwise.
2980 GREAT FDB DOCOL,SWAP,LESS
2984 * ( n1 n2 n3 --- n2 n3 n1 )
2985 * Rotate the top three words on stack,
2986 * bringing the third word to the top.
2997 * ROT FDB DOCOL,TOR,SWAP,FROMR,SWAP
3004 FCC 'SPAC' ; 'SPACE'
3007 SPACE FDB DOCOL,BL,EMIT
3011 * ( n0 n1 --- min(n0,n1) )
3012 * Leave the minimum of the top two integers.
3013 * Being too greedy here, but, whatever.
3024 * MIN FDB DOCOL,OVER,OVER,GREAT,ZBRAN
3031 * ( n0 n1 --- max(n0,n1) )
3032 * Leave the maximum of the top two integers.
3033 * Really should leave this as in the model.
3044 * MAX FDB DOCOL,OVER,OVER,LESS,ZBRAN
3063 * DDUP FDB DOCOL,DUP,ZBRAN
3064 * FDB DDUP2-*-NATWID
3068 * ######>> screen 39 <<
3073 * Change top integer to its sign.
3075 FCC 'SIGNU' ; 'SIGNUM'
3083 SIGNUP SEX ; Couldn't they have called SignEXtend EXT instead?
3084 STD ,U ; Am I too much of a prude?
3086 * 6800 model version should be something like this:
3097 * ( adr1 direction --- adr2 )
3098 * TRAVERSE the symbol name.
3099 * If direction is 1, find the end.
3100 * If direction is -1, find the beginning.
3102 FCC 'TRAVERS' ; 'TRAVERSE'
3106 BSR SIGNUE ; Convert negative to -, zero or positive to 1.
3107 LDD ,U++ ; Still in D, but we have to pop it anyway.
3108 LDX ,U ; If D is 1 or -1, so is B.
3110 TRAVLP LEAX B,X ; Don't look at the one we start at.
3111 CMPA ,X ; Not sure why we aren't just doing LDA ,X ; BPL.
3115 * Doing this in 6809 just because it can be done may be getting too greedy.
3116 * TRAV FDB DOCOL,SWAP
3117 * TRAV2 FDB OVER,PLUS,LIT8
3119 * FDB OVER,CAT,LESS,ZBRAN
3120 * FDB TRAV2-*-NATWID
3126 * Fetch CURRENT as a per-USER constant.
3128 FCC 'LATES' ; 'LATEST'
3131 LATEST FDB DOCOL,CURENT,AT,AT
3133 * LATEST FDB *+NATWID
3134 * Getting too greedy:
3139 * LDD CURENT+NATWID,PCR
3141 * PSHU X ; Leave the address in X.
3150 * Too greedy, too many smantic holes to fall through.
3151 * If the address at the CFA is made relative,
3152 * this is part of the code that would be affected
3153 * if it is in native CPU code.
3156 * Wanted to do these as INCREMENTERs,
3157 * but I need to stick with the model as much as possible,
3158 * (mostly, LOL) adding code only to make the model more clear.
3160 * Convert PFA to LFA, unchecked. (Bump back from contents to allocation link.)
3173 * Convert PFA to CFA, unchecked. (Bump back from contents to characterist code link.)
3178 * CFA FDB DOCOL,TWO,SUB
3179 CFA FDB DOCOL,NATWC,SUB
3184 * Convert PFA to NFA. (Bump back from contents to beginning of symbol name.)
3192 FDB SUB,ONE,MINUS,TRAV
3197 * Convert NFA to PFA. (Bump up from beginning of symbol name to contents.)
3202 PFA FDB DOCOL,ONE,TRAV,LIT8
3208 * ######>> screen 40 <<
3211 * Save the parameter stack pointer in CSP for compiler checks.
3216 SCSP FDB DOCOL,SPAT,CSP,STORE
3220 * ( 0 n --- ) ( *** )
3221 * ( true n --- IN BLK ) ( anything *** nothing )
3222 * If flag is false, do nothing.
3223 * If flag is true, issue error MESSAGE and QUIT or ABORT, via ERROR.
3224 * Leaves cursor position (IN)
3225 * and currently loading block number (BLK) on stack, for analysis.
3227 * This one is too important to be high-level Forth codes.
3228 * When we have an error, we want to disturb as little as possible.
3229 * But fixing that cascades through ERROR and MESSAGE
3230 * into the disk block system.
3231 * And we aren't ready for that yet.
3233 FCC '?ERRO' ; '?ERROR'
3241 ** this doesn't work anyway: QERROR LBR ERROR
3242 QERR FDB DOCOL,SWAP,ZBRAN
3250 * STATE is compiling:
3252 * STATE is compiling:
3253 * ( --- IN BLK ) ( anything *** nothing )
3254 * ERROR if not compiling.
3256 FCC '?COM' ; '?COMP'
3259 QCOMP FDB DOCOL,STATE,AT,ZEQU,LIT8
3265 * STATE is executing:
3267 * STATE is executing:
3268 * ( --- IN BLK ) ( anything *** nothing )
3269 * ERROR if not executing.
3271 FCC '?EXE' ; '?EXEC'
3274 QEXEC FDB DOCOL,STATE,AT,LIT8
3280 * ( n1 n1 --- ) ( *** )
3281 * ( n1 n2 --- IN BLK ) ( anything *** nothing )
3282 * ERROR if top two are unequal.
3283 * MESSAGE says compiled conditionals do not match.
3285 FCC '?PAIR' ; '?PAIRS'
3288 QPAIRS FDB DOCOL,SUB,LIT8
3294 * CSP and parameter stack are balanced (equal):
3296 * CSP and parameter stack are not balanced (unequal):
3297 * ( --- IN BLK ) ( anything *** nothing )
3298 * ERROR if return/control stack is not at same level as last !CSP.
3299 * Usually indicates that a definition has been left incomplete.
3304 QCSP FDB DOCOL,SPAT,CSP,AT,SUB,LIT8
3312 * No active BLK input:
3313 * ( --- IN BLK ) ( anything *** nothing )
3314 * ERROR if not loading, i. e., if BLK is zero.
3316 FCC '?LOADIN' ; '?LOADING'
3319 QLOAD FDB DOCOL,BLK,AT,ZEQU,LIT8
3324 * ######>> screen 41 <<
3327 * Compile an in-line literal value from the instruction stream.
3329 FCC 'COMPIL' ; 'COMPILE'
3332 * COMPIL FDB DOCOL,QCOMP,FROMR,TWOP,DUP,TOR,AT,COMMA
3333 * COMPIL FDB DOCOL,QCOMP,FROMR,NATP,DUP,TOR,AT,COMMA
3334 COMPIL FDB DOCOL,QCOMP,FROMR,DUP,NATP,TOR,AT,COMMA
3339 * Clear the compile state bit(s) (shift to interpret).
3343 LBRAK FDB DOCOL,ZERO,STATE,STORE
3350 * Set the compile state bit(s) (shift to compile).
3354 RBRAK FDB DOCOL,LIT8
3361 * Toggle SMUDGE bit of LATEST definition header,
3362 * to hide it until defined or reveal it after definition.
3364 FCC 'SMUDG' ; 'SMUDGE'
3367 SMUDGE FDB DOCOL,LATEST,LIT8
3374 * Set the conversion base to sixteen (b00010000).
3381 FCB 16 ; decimal sixteen
3387 * Set the conversion base to ten (b00001010).
3389 FCC 'DECIMA' ; 'DECIMAL'
3394 FCB 10 ; decimal ten
3398 * ######>> screen 42 <<
3400 * ( --- ) ( IP *** )
3401 * Pop the saved IP and use it to
3402 * compile the latest symbol as a reference to a ;CODE definition;
3403 * overwrite the code field of the symbol found by LATEST
3404 * with the address of the low-level characteristic code
3405 * provided in the defining definition.
3406 * Look closely at where things return, consider the operation of R> and >R .
3408 * The machine-level code which follows (;CODE) in the instruction stream
3409 * is not executed by the defining symbol,
3410 * but becomes the characteristic of the defined symbol.
3411 * This is the usual way to generate the characteristics of VARIABLEs,
3412 * CONSTANTs, COLON definitions, etc., when FORTH compiles itself.
3414 * Finally, note that, if code shifts from low level back to high
3415 * (native CPU machine code calling into a list of FORTH codes),
3416 * the low level code can't just call a high-level definition.
3417 * Leaf definitions can directly call other leaf definitions,
3418 * but not non-leafs.
3419 * It will need an anonymous list, probably embedded in the low-level code,
3420 * and Y and X will have to be set appropriately before entering the list.
3422 FCC '(;CODE' ; '(;CODE)'
3425 * PSCODE FDB DOCOL,FROMR,TWOP,LATEST,PFA,CFA,STORE
3426 PSCODE FDB DOCOL,FROMR ; Y/IP is post-inc, needs no adjustment.
3427 FDB LATEST,PFA,CFA,STORE
3432 * ?CSP to see if there are loose ends in the defining definition
3433 * before shifting to the assembler,
3434 * compile (;CODE) in the defining definition's instruction stream,
3435 * shift to interpreting,
3436 * make the ASSEMBLER vocabulary current,
3437 * and !CSP to mark the stack
3438 * in preparation for assembling low-level code.
3439 * Note that ;CODE, unlike DOES>, is IMMEDIATE,
3440 * and compiles (;CODE),
3441 * which will do the actual work of changing
3442 * the LATEST definition's characteristic when the defining word runs.
3443 * Assembly is done by the interpreter, rather than the compiler.
3444 * I could have avoided the anomalous three-byte code fields by
3446 * Note that the ASSEMBLER is not part of the model (at this time).
3447 * That means that, until the assembler is ready,
3448 * if you want to define low-level words,
3449 * you have to poke (comma) in hand-assembled stuff.
3452 FCC ';COD' ; ';CODE'
3455 SEMIC FDB DOCOL,QCSP,COMPIL,PSCODE,SMUDGE,LBRAK,QSTACK
3457 * note: "QSTACK" will be replaced by "ASSEMBLER" later
3459 * ######>> screen 43 <<
3462 * Make the word currently being defined
3463 * build a header for DOES> definitions.
3464 * Actually just compiles a CONSTANT zero
3465 * which can be overwritten later by DOES>.
3466 * Since the fig models were established, this technique has been deprecated.
3468 * Note that <BUILDS is not IMMEDIATE,
3469 * and therefore executes during a definition's run-time,
3470 * rather than its compile-time.
3471 * It is not intended to be used directly,
3472 * but rather so that one definition word can build another.
3473 * Also, note that nothing particularly special happens
3474 * in the defining definition until DOES> executes.
3475 * The name <BUILDS is intended to be a reminder of what is about to occur.
3477 * <BUILDS probably should have compiled an ERROR instead of a ZERO CONSTANT.
3479 FCC '<BUILD' ; '<BUILDS'
3482 BUILDS FDB DOCOL,ZERO,CON
3486 * ( --- ) ( IP *** ) C
3487 * Define run-time behavior of definitions compiled/defined
3488 * by a high-level defining definition --
3489 * the FORTH equivalent of a compiler-compiler.
3490 * DOES> assumes that the LATEST symbol table entry
3491 * has at least one word of parameter field,
3492 * which <BUILDS provides.
3493 * Note that DOES> is also not IMMEDIATE.
3495 * When the defining word containing DOES> executes the DOES> icode,
3496 * it overwrites the LATEST symbol's CFA with jsr <XDOES,
3497 * overwrites the first word of that symbol's parameter field with its own IP,
3498 * and pops the previous IP from the return stack.
3499 * The icodes which follow DOES> in the stream
3500 * do not execute at the defining word's run-time.
3502 * Examining XDOES in the virtual machine shows
3503 * that the defined word will execute those icodes
3504 * which follow DOES> at its own run-time.
3506 * The advantage of this kind of behaviour,
3507 * which you will also note in ;CODE,
3508 * is that the defined word can contain
3509 * both operations and data to be operated on.
3510 * This is how FORTH data objects define their own behavior.
3512 * Finally, note that the effective parameter field for DOES> definitions
3513 * starts two NATWID words after the CFA, instead of just one
3514 * (four bytes instead of two in a sixteen-bit addressing Forth).
3516 * VOCABULARYs will use this. See definition of word FORTH.
3518 FCC 'DOES' ; 'DOES>'
3521 * DOES FDB DOCOL,FROMR,TWOP,LATEST,PFA,STORE
3522 DOES FDB DOCOL,FROMR ; Y/IP is post-inc, needs no adjustment.
3523 FDB LATEST,PFA,STORE
3526 * ( --- PFA+NATWID ) ( *** IP )
3527 * Characteristic of a DOES> defined word.
3528 * The characteristics of DOES> definitions are written in high-level
3529 * Forth codes rather than native CPU machine level code.
3530 * The first parameter word points to the high-level characteristic.
3531 * This routine's job is to push the IP,
3532 * load the high level characteristic pointer in IP,
3533 * and leave the address following the characteristic pointer on the stack
3534 * so the parameter field can be accessed.
3535 DODOES LDD ,S ; Keep the return address.
3536 STY ,S ; Save/nest the current IP on the return stack.
3537 LDY NATWID,X ; First parameter is new IP.
3538 LEAX 2*NATWID,X ; Address of second parameter.
3540 TFR D,PC ; Synthetic return.
3542 * From the 6800 model:
3545 * LDX RP make room on return stack
3549 * STA 2,X push return address
3551 * LDX W get addr of pointer to run-time code
3554 * STX N stash it in scratch area
3555 * LDX 0,X get new IP
3557 * CLRA ; get address of parameter
3561 * PSHS B ; and push it on data stack
3565 * ######>> screen 44 <<
3567 * ( strptr --- strptr+1 count )
3568 * Convert counted string to string and count.
3569 * (Fetch the byte at strptr, post-increment.)
3571 FCC 'COUN' ; 'COUNT'
3574 COUNT FDB DOCOL,DUP,ONEP,SWAP,CAT
3578 * ( strptr count --- )
3579 * EMIT count characters at strptr.
3584 TYPE FDB DOCOL,DDUP,ZBRAN
3586 FDB OVER,PLUS,SWAP,XDO
3587 TYPE2 FDB I,CAT,EMIT,XLOOP
3595 * ( strptr count1 --- strptr count2 )
3596 * Supress trailing blanks (subtract count of trailing blanks from strptr).
3598 FCC '-TRAILIN' ; '-TRAILING'
3601 DTRAIL FDB DOCOL,DUP,ZERO,XDO
3602 DTRAL2 FDB OVER,OVER,PLUS,ONE,SUB,CAT,BL
3614 * TYPE counted string out of instruction stream (updating IP).
3619 * PDOTQ FDB DOCOL,R,TWOP,COUNT,DUP,ONEP
3620 * PDOTQ FDB DOCOL,R,NATP,COUNT,DUP,ONEP
3621 PDOTQ FDB DOCOL,R,COUNT,DUP,ONEP
3622 FDB FROMR,PLUS,TOR,TYPE
3627 * { ." something-to-be-printed " } typical input
3628 * Use WORD to parse to trailing quote;
3629 * if compiling, compile XDOTQ and string parsed,
3630 * otherwise, TYPE string.
3640 FDB COMPIL,PDOTQ,WORD
3641 FDB HERE,CAT,ONEP,ALLOT,BRAN
3643 DOTQ1 FDB WORD,HERE,COUNT,TYPE
3646 * ######>> screen 45 <<
3647 * ======>> 126 <<== MACHINE DEPENDENT
3649 * ( --- IN BLK ) ( anything *** nothing )
3650 * ERROR if parameter stack out of bounds.
3652 * But checking whether the stack is in bounds or not
3653 * really should not use the stack.
3654 * And there really should be a ?RSTACK, as well.
3656 FCC '?STAC' ; '?STACK'
3659 QSTACK FDB DOCOL,LIT8
3662 * But why use that instead of XSPZER (S0)?
3663 * Multi-user or multi-tasking would not want that.
3665 * FDB PORIG,AT,TWO,SUB,SPAT,LESS,ONE
3666 FDB PORIG,AT,SPAT,LESS,ONE ; Not post-decrement push.
3668 * prints 'empty stack'
3671 * Here, we compare with a value at least 128
3672 * higher than dict. ptr. (DICTPT)
3674 FCB $80 ; This is a rough check anyway, leave it as is.
3677 FDB TWO ; NOT the NATWID constant!
3679 * prints 'full stack'
3683 * ======>> 127 << this word's function
3684 * is done by ?STACK in this version
3689 *QFREE FDB DOCOL,SPAT,HERE,LIT8
3691 * FDB PLUS,LESS,TWO,QERR,SEMIS ; This TWO is not NATWID!
3693 * ######>> screen 46 <<
3696 * ***** Check that this is how it works here:
3697 * Get up to n-1 characters from the keyboard,
3698 * storing at buffer and echoing, with backspace editing,
3699 * quitting when a CR is read.
3700 * Terminate it with a NUL.
3702 FCC 'EXPEC' ; 'EXPECT'
3705 EXPECT FDB DOCOL,OVER,PLUS,OVER,XDO ; brace the buffer area
3706 * EXPEC2 FDB KEY,DUP,LIT8
3708 FDB LIT,$1C,SHOTOS ; DBG
3711 FDB PORIG,AT,EQUAL,ZBRAN ; check for backspacing
3714 FCB 8 ( backspace character to emit )
3715 FDB OVER,I,EQUAL,DUP,FROMR,TWO,SUB,PLUS ; back I up TWO characters
3719 FCB $D ( carriage return )
3722 FDB LEAVE,DROP,BL,ZERO,BRAN ; I think this is the NUL terminator.
3725 EXPEC5 FDB I,CSTORE,ZERO,I,ONEP,STORE
3726 EXPEC6 FDB EMIT,XLOOP
3733 * EXPECT 128 (TWID) characters to TIB.
3735 FCC 'QUER' ; 'QUERY'
3738 QUERY FDB DOCOL,TIB,AT,COLUMS
3739 FDB AT,EXPECT,ZERO,IN,STORE
3744 * End interpretation of a line or screen, and/or prepare for a new block.
3745 * Note that the name of this definition is an empty string,
3746 * so it matches on the terminating NUL in the terminal or block buffer.
3747 FCB $C1 immediate < carriage return >
3750 NULL FDB DOCOL,BLK,AT,ZBRAN
3753 FDB ZERO,IN,STORE,BLK,AT,BSCR,MOD
3755 * check for end of screen
3758 FDB QEXEC,FROMR,DROP
3761 NULL2 FDB FROMR,DROP
3764 * ######>> screen 47 <<
3767 * Fill n bytes at adr with b.
3772 FILL FDB DOCOL,SWAP,TOR,OVER,CSTORE,DUP,ONEP
3773 FDB FROMR,ONE,SUB,CMOVE
3778 * Fill n bytes with 0.
3780 FCC 'ERAS' ; 'ERASE'
3783 ERASE FDB DOCOL,ZERO,FILL
3788 * Fill n bytes with ASCII SPACE.
3790 FCC 'BLANK' ; 'BLANKS'
3793 BLANKS FDB DOCOL,BL,FILL
3798 * Format a character at the left of the HLD output buffer.
3803 HOLD FDB DOCOL,LIT,$FFFF,HLD,PSTORE,HLD,AT,CSTORE
3808 * Give the address of the output PAD buffer.
3809 * PAD points to the end of a 68 byte buffer for numeric conversion.
3814 PAD FDB DOCOL,HERE,LIT8
3819 * ######>> screen 48 <<
3822 * Scan a string terminated by the character c or ASCII NUL out of input;
3823 * store symbol at WORDPAD with leading count byte and trailing ASCII NUL.
3824 * Leading c are passed over, per ENCLOSE.
3825 * Scans from BLK, or from TIB if BLK is zero.
3826 * May overwrite the numeric conversion pad,
3827 * if really long (length > 31) symbols are scanned.
3832 WORD FDB DOCOL,BLK,AT,ZBRAN
3834 FDB BLK,AT,BLOCK,BRAN
3837 WORD3 FDB IN,AT,PLUS,SWAP,ENCLOS,HERE,LIT8
3839 FDB BLANKS,IN,PSTORE,OVER,SUB,TOR,R,HERE
3840 FDB CSTORE,PLUS,HERE,ONEP,FROMR,CMOVE
3843 * ######>> screen 49 <<
3845 * ( d1 string --- d2 adr )
3846 * Convert the text at string into a number, accumulating the result into d1,
3847 * leaving adr pointing to the first character not converted.
3848 * If DPL is non-negative at entry,
3849 * accumulates the number of characters converted into DPL.
3851 FCC '(NUMBER' ; '(NUMBER)'
3855 PNUMB2 FDB ONEP,DUP,TOR,CAT,BASE,AT,DIGIT,ZBRAN
3857 FDB SWAP,BASE,AT,USTAR,DROP,ROT,BASE
3858 FDB AT,USTAR,DPLUS,DPL,AT,ONEP,ZBRAN
3861 PNUMB3 FDB FROMR,BRAN
3868 * Convert text at ctstr to a double integer,
3869 * taking the 0 ERROR if the conversion is not valid.
3870 * If a decimal point is present,
3871 * accumulate the count of digits to the decimal point's right into DPL
3872 * (negative DPL at exit indicates single precision).
3873 * ctstr is a counted string
3874 * -- the first byte at ctstr is the length of the string,
3875 * but NUMBER ignores the count and expects a NUL terminator instead.
3877 FCC 'NUMBE' ; 'NUMBER'
3880 NUMB FDB DOCOL,ZERO,ZERO,ROT,DUP,ONEP,CAT,LIT8
3882 FDB EQUAL,DUP,TOR,PLUS,LIT,$FFFF
3883 NUMB1 FDB DPL,STORE,PNUMB,DUP,CAT,BL,SUB
3888 FDB SUB,ZERO,QERR,ZERO,BRAN
3890 NUMB2 FDB DROP,FROMR,ZBRAN
3896 * ( --- locptr length true ) { -FIND name } typical input
3898 * Parse a word, then FIND,
3899 * first in the definition vocabulary,
3900 * then in the CONTEXT (interpretation) vocabulary, if necessary.
3901 * Returns what (FIND) returns, flag and optional location and length.
3903 FCC '-FIN' ; '-FIND'
3906 DFIND FDB DOCOL,BL,WORD,HERE,CONTXT,AT,AT
3907 FDB PFIND,DUP,ZEQU,ZBRAN
3909 FDB DROP,HERE,LATEST,PFIND
3912 * ######>> screen 50 <<
3914 * ( anything --- nothing ) ( anything *** nothing )
3915 * An indirection for ABORT, for ERROR,
3916 * which may be modified carefully.
3918 FCC '(ABORT' ; '(ABORT)'
3921 PABORT FDB DOCOL,ABORT
3926 FCC 'ERRO' ; 'ERROR'
3929 * This really should not be high level, according to best practices.
3930 * But fixing that cascades through MESSAGE,
3931 * requiring re-architecting the disk block system.
3932 * First, we need to get this transliteration running.
3933 ERROR FDB DOCOL,WARN,AT,ZLESS
3938 * 0 to print error #
3939 * and 1 to print error message from disc
3941 ERROR2 FDB HERE,COUNT,TYPE,PDOTQ
3944 FDB MESS,SPSTOR,IN,AT,BLK,AT,QUIT
3949 * Mask byte at adr with n.
3950 * Not in FIG, don't need it for 8 bit characters after all.
3952 * FCC 'CMAS' ; 'CMASK'
3955 * CMASK FDB *+NATWID
3963 * Mask high bit of tail of name in PAD buffer.
3964 * Not in FIG, need it for 8 bit characters.
3966 FCC 'IDFLA' ; 'IDFLAT'
3971 LDB ,X ; get the count
3973 LDA B,X ; point to the tail
3974 ANDA #$7F ; Clear the EndOfName flag bit.
3979 * Print definition's name from its NFA.
3984 IDDOT FDB DOCOL,PAD,LIT8
3987 FCB $5F ( underline )
3988 FDB FILL,DUP,PFA,LFA,OVER,SUB,PAD
3989 * FDB SWAP,CMOVE,PAD,COUNT,LIT8
3997 * ######>> screen 51 <<
3999 * ( --- ) { CREATE name } input
4000 * Parse a name (length < 32 characters) and create a header,
4001 * reporting first duplicate found in either the defining vocabulary
4002 * or the context (interpreting) vocabulary.
4003 * Install the header in the defining vocabulary
4004 * with CFA dangerously pointing to the parameter field.
4005 * Leave the name SMUDGEd.
4007 FCC 'CREAT' ; 'CREATE'
4010 CREATE FDB DOCOL,DFIND,ZBRAN
4019 CREAT2 FDB HERE,DUP,CAT,WIDTH,AT,MIN
4020 FDB ONEP,ALLOT,DUP,LIT8
4021 FCB ($80|FSMUDG) ; Bracket the name.
4022 FDB TOGGLE,HERE,ONE,SUB,LIT8
4024 FDB TOGGLE,LATEST,COMMA,CURENT,AT,STORE
4025 * FDB HERE,TWOP,COMMA
4029 * ######>> screen 52 <<
4032 * { [COMPILE] name } typical use
4033 * -DFIND next WORD and COMPILE it, literally;
4034 * used to compile immediate definitions into words.
4036 FCC '[COMPILE' ; '[COMPILE]'
4039 BCOMP FDB DOCOL,DFIND,ZEQU,ZERO,QERR,DROP,CFA,COMMA
4043 * ( n --- ) if compiling. P
4044 * ( n --- n ) if interpreting.
4045 * Compile n as a literal, if compiling.
4047 FCC 'LITERA' ; 'LITERAL'
4050 LITER FDB DOCOL,STATE,AT,ZBRAN
4052 FDB COMPIL,LIT,COMMA
4056 * ( d --- ) if compiling. P
4057 * ( d --- d ) if interpreting.
4058 * Compile d as a double literal, if compiling.
4060 FCC 'DLITERA' ; 'DLITERAL'
4063 DLITER FDB DOCOL,STATE,AT,ZBRAN
4065 FDB SWAP,LITER,LITER ; Just two literals in the right order.
4068 * ######>> screen 53 <<
4071 * Interpret or compile, according to STATE.
4072 * Searches words parsed in dictionary first, via -FIND,
4073 * then checks for valid NUMBER.
4074 * Pushes or COMPILEs double literal if NUMBER leaves DPL non-negative.
4075 * ERROR checks the stack via ?STACK before returning to its caller.
4077 FCC 'INTERPRE' ; 'INTERPRET'
4081 INTER2 FDB DFIND,ZBRAN
4091 INTER5 FDB HERE,NUMB,DPL,AT,ONEP,ZBRAN
4095 INTER6 FDB DROP,LITER
4096 INTER7 FDB QSTACK,BRAN
4098 * FDB SEMIS never executed
4101 * ######>> screen 54 <<
4104 * Toggle precedence bit of LATEST definition header.
4105 * During compiling, most symbols scanned are compiled.
4106 * IMMEDIATE definitions execute whenever the outer INTERPRETer scans them,
4107 * but may be compiled via ' (TICK).
4109 FCC 'IMMEDIAT' ; 'IMMEDIATE'
4112 IMMED FDB DOCOL,LATEST,LIT8
4118 * ( --- ) { VOCABULARY name } input
4119 * Create a vocabulary entry with a flag for terminating vocabulary searches.
4120 * Store the current search context in it for linking.
4121 * At run-time, VOCABULARY makes itself the CONTEXT vocabulary.
4123 FCC 'VOCABULAR' ; 'VOCABULARY'
4126 VOCAB FDB DOCOL,BUILDS,LIT,$81A0,COMMA,CURENT,AT,CFA
4127 FDB COMMA,HERE,VOCLIN,AT,COMMA,VOCLIN,STORE,DOES
4128 * DOVOC FDB TWOP,CONTXT,STORE
4129 DOVOC FDB NATP,CONTXT,STORE
4134 * Note: FORTH does not go here in the rom-able dictionary,
4135 * since FORTH is a type of variable.
4137 * (Should make a proper architecture for this at some point.)
4142 * Makes the current interpretation CONTEXT vocabulary
4143 * also the CURRENT defining vocabulary.
4145 FCC 'DEFINITION' ; 'DEFINITIONS'
4148 DEFIN FDB DOCOL,CONTXT,AT,CURENT,STORE
4153 * Parse out a comment and toss it away.
4154 * Leaves the first 32 characters in WORDPAD, which may or may not be useful.
4158 PAREN FDB DOCOL,LIT8
4163 * ######>> screen 55 <<
4165 * ( anything *** nothing )
4166 * Clear return stack.
4167 * Then INTERPRET and, if not compiling, prompt with OK,
4173 QUIT FDB DOCOL,ZERO,BLK,STORE
4176 * Here is the outer interpretter
4177 * which gets a line of input, does it, prints " OK"
4179 QUIT2 FDB RPSTOR,CR,QUERY,INTERP,STATE,AT,ZEQU
4187 * FDB SEMIS ( never executed )
4190 * ( anything --- nothing ) ( anything *** nothing )
4191 * Clear parameter stack,
4192 * set STATE to interpret and BASE to DECIMAL,
4193 * return to input from terminal,
4194 * restore DRIVE OFFSET to 0,
4195 * print out "Forth-68",
4196 * set interpret and define vocabularies to FORTH,
4197 * and finally, QUIT.
4198 * Used to force the system to a known state
4199 * and return control to the initial INTERPRETer.
4201 FCC 'ABOR' ; 'ABORT'
4204 ABORT FDB DOCOL,SPSTOR,DEC,QSTACK,DRZERO,CR,PDOTQ
4209 * FDB SEMIS never executed
4212 * ######>> screen 56 <<
4213 * bootstrap code... moves rom contents to ram :
4220 * Ultimately, we want position indepence,
4221 * so I'm using PCR where it seems reasonable.
4222 CENT LDS SINIT,PCR ; Get a useable return stack, at least.
4223 LDA #IUPDP ; This is not relative to PC.
4224 TFR A,DP ; And a useable direct page, too.
4225 SETDP IUPDP ; (For good measure.)
4227 * We'll keep this here for the time being.
4228 * There are better ways to do this, of course.
4229 * Re-architect, re-architect.
4231 STX <XFENCE ; Borrow this variable for a loop terminator.
4232 LEAY REND,PCR ; top of destination
4233 LEAX ERAM,PCR ; top of stuff to move
4235 STA ,-Y ; move TASK & FORTH to ram
4239 * CENT LDS #REND-1 top of destination
4240 * LDX #ERAM top of stuff to move
4243 * PSHS A ; move TASK & FORTH to ram
4247 * LDS #XFENCE-1 put stack at a safe place for now
4248 * But that is taken care of.
4270 WENT LDS SINIT,PCR ; Get a useable return stack, at least.
4271 LDA #IUPDP ; This is not relative to PC.
4272 TFR A,DP ; And a useable direct page, too.
4273 SETDP IUPDP ; (For good measure.)
4276 PSHS X ; for loop termination
4277 CLRB ; Yes, I'm being a little ridiculous. Only a little.
4279 LEAY XFENCE-UORIG,Y ; top of destination
4280 LEAX FENCIN,PCR ; top of stuff to move
4281 WARM2 LDD ,--X ; All entries are 16 bit.
4285 LEAS 2,S ; But we'll reset the return stack shortly, anyway.
4286 * WENT LDS #XFENCE-1 top of destination
4287 * LDX #FENCIN top of stuff to move
4295 * S is already there.
4297 * STX UP init user ram pointer
4298 * UP is already there (DP).
4301 LEAY ABORT+NATWID,PCR ; IP never points to DOCOL!
4303 NOP Here is a place to jump to special user
4304 NOP initializations such as I/0 interrups
4307 * For systems with TRACE:
4309 * STX TRLIM clear trace mode
4310 STX <TRLIM clear trace mode (both bytes)
4312 * STX BRKPT clear breakpoint address
4313 STX <BRKPT clear breakpoint address
4314 * JMP RPSTOR+2 start the virtual machine running !
4315 LBSR RPSTOR+NATWID start the virtual machine running !
4316 LBRA NEXT ; But we must also give RP! someplace to return.
4317 * RP! sets up the return stack pointer, then Y references abort.
4319 * Here is the stuff that gets copied to ram :
4320 * (not * at address $140:)
4321 * at an appropriate address:
4323 RAM FDB $3000,$3000,0,0
4327 * Makes FORTH the current interpretation vocabulary.
4328 * In order to make this ROMmable, this entry is set up as the tail-end,
4329 * and copied to RAM in the start-up code.
4330 * We want a more elegant solution to this, too. Greedy, maybe.
4332 FCC 'FORT' ; 'FORTH'
4334 FDB NOOP-7 ; Note that this does not link to COLD!
4335 RFORTH FDB DODOES,DOVOC,$81A0,TASK-7
4337 FCC "(C) Forth Interest Group, 1979"
4342 RTASK FDB DOCOL,SEMIS
4343 ERAM FCC "David Lion"
4346 * ######>> screen 57 <<
4349 * Sign extend n0 to a double integer.
4353 FDB COLD-7 ; Note that this does not link to FORTH (RFORTH)!
4354 STOD FDB DOCOL,DUP,ZLESS,MINUS
4360 * ( multiplier multiplicand --- product )
4361 * Signed word multiply.
4366 LBSR USTAR+NATWID ; or [USTAR,PCR]?
4367 LEAU NATWID,U ; Drop high word.
4375 * ( dividend divisor --- remainder quotient )
4376 * M/ in word-only form, i. e., signed division of 2nd word by top word,
4377 * yielding signed word quotient and remainder.
4382 SLMOD FDB DOCOL,TOR,STOD,FROMR,USLASH
4386 * ( dividend divisor --- quotient )
4387 * Signed word divide without remainder.
4391 SLASH FDB DOCOL,SLMOD,SWAP,DROP
4395 * ( dividend divisor --- remainder )
4396 * Remainder function, result takes sign of dividend.
4401 MOD FDB DOCOL,SLMOD,DROP
4405 * ( multiplier multiplicand divisor --- remainder quotient )
4406 * Signed precise division of product:
4407 * multiply 2nd and 3rd words on stack
4408 * and divide the 31-bit product by the top word,
4409 * leaving both quotient and remainder.
4410 * Remainder takes sign of product.
4411 * Guaranteed not to lose significant bits in 16 bit integer math.
4413 FCC '*/MO' ; '*/MOD'
4416 SSMOD FDB DOCOL,TOR,USTAR,FROMR,USLASH
4420 * ( multiplier multiplicand divisor --- quotient )
4421 * */MOD without remainder.
4426 SSLASH FDB DOCOL,SSMOD,SWAP,DROP
4430 * ( ud1 u1 --- u2 ud2 )
4431 * U/ with an (unsigned) double quotient.
4432 * Guaranteed not to lose significant bits in 32 bit / 16 bit bit integer math,
4433 * if you are prepared to deal with the extra 16 bits of result.
4435 FCC 'M/MO' ; 'M/MOD'
4438 MSMOD FDB DOCOL,TOR,ZERO,R,USLASH
4439 FDB FROMR,SWAP,TOR,USLASH,FROMR
4445 * Convert the top of stack to its absolute value.
4450 ABS FDB DOCOL,DUP,ZLESS,ZBRAN
4458 * Convert the top double to its absolute value.
4463 DABS FDB DOCOL,DUP,ZLESS,ZBRAN
4468 * ######>> screen 58 <<
4472 * Least Recently Used buffer.
4473 * Really should be with FIRST and LIMIT in the per-task table.
4482 * Most Recently Used buffer.
4483 * Really should be with FIRST and LIMIT in the per-task table.
4491 * ( buffer1 --- buffer2 f )
4492 * Bump to next buffer,
4493 * flag false if result is PREVious buffer,
4494 * otherwise flag true.
4495 * Used in the LRU allocation routines.
4502 FDB PLUS,DUP,LIMIT,EQUAL,ZBRAN
4505 PBUF2 FDB DUP,PREV,AT,SUB
4510 * Mark PREVious buffer dirty, in need of being written out.
4512 FCC 'UPDAT' ; 'UPDATE'
4515 UPDATE FDB DOCOL,PREV,AT,AT,LIT,$8000,OR,PREV,AT,STORE
4520 * Mark all buffers empty.
4521 * Standard method of discarding changes.
4523 FCC 'EMPTY-BUFFER' ; 'EMPTY-BUFFERS'
4526 MTBUF FDB DOCOL,FIRST,LIMIT,OVER,SUB,ERASE
4531 * Clear the current offset to the block numbers in the drive interface.
4532 * The drives need to be re-architected.
4533 * Would be cool to have RAM and ROM drives supported
4534 * in addition to regular physical persistent store.
4539 DRZERO FDB DOCOL,ZERO,OFSET,STORE
4542 * ======>> 174 <<== system dependant word
4544 * Set the current offset in the drive interface to reference the second drive.
4545 * The hard-coded number in there needs to be in a table.
4550 DRONE FDB DOCOL,LIT,$07D0,OFSET,STORE
4553 * ######>> screen 59 <<
4556 * Get a free buffer,
4557 * assign it to block n,
4558 * return buffer address.
4559 * Will free a buffer by writing it, if necessary.
4560 * Does not actually read the block.
4561 * A bug in the fig LRU algorithm, which I have not fixed,
4562 * gives the PREVious buffer if USE gets set to PREVious.
4563 * (The bug is that USE sometimes gets set to PREVious.)
4564 * This bug sometimes causes sector moves to become sector fills.
4566 FCC 'BUFFE' ; 'BUFFER'
4569 BUFFER FDB DOCOL,USE,AT,DUP,TOR
4570 BUFFR2 FDB PBUF,ZBRAN
4572 FDB USE,STORE,R,AT,ZLESS
4575 * FDB R,TWOP,R,AT,LIT,$7FFF,AND,ZERO,RW
4576 FDB R,NATP,R,AT,LIT,$7FFF,AND,ZERO,RW
4577 * BUFFR3 FDB R,STORE,R,PREV,STORE,FROMR,TWOP
4578 BUFFR3 FDB R,STORE,R,PREV,STORE,FROMR,NATP
4581 * ######>> screen 60 <<
4584 * Get BUFFER containing block n, relative to OFFSET.
4585 * If block n is not in a buffer, bring it in.
4586 * Returns buffer address.
4588 FCC 'BLOC' ; 'BLOCK'
4591 BLOCK FDB DOCOL,OFSET,AT,PLUS,TOR
4592 FDB PREV,AT,DUP,AT,R,SUB,DUP,PLUS,ZBRAN
4594 BLOCK3 FDB PBUF,ZEQU,ZBRAN
4596 * FDB DROP,R,BUFFER,DUP,R,ONE,RW,TWO,SUB
4597 FDB DROP,R,BUFFER,DUP,R,ONE,RW,NATWC,SUB
4598 BLOCK4 FDB DUP,AT,R,SUB,DUP,PLUS,ZEQU,ZBRAN
4601 * BLOCK5 FDB FROMR,DROP,TWOP
4602 BLOCK5 FDB FROMR,DROP,NATP
4605 * ######>> screen 61 <<
4607 * ( line screen --- buffer C/L)
4608 * Bring in the sector containing the specified line of the specified screen.
4609 * Returns the buffer address and the width of the screen.
4610 * Screen number is relative to OFFSET.
4611 * The line number may be beyond screen 4,
4612 * (LINE) will get the appropriate screen.
4614 FCC '(LINE' ; '(LINE)'
4617 PLINE FDB DOCOL,TOR,LIT8
4619 FDB BBUF,SSMOD,FROMR,BSCR,STAR,PLUS,BLOCK,PLUS,LIT8
4624 * ( line screen --- )
4625 * Print the line of the screen as found by (LINE), suppress trailing BLANKS.
4627 FCC '.LIN' ; '.LINE'
4630 DLINE FDB DOCOL,PLINE,DTRAIL,TYPE
4635 * If WARNING is 0, print "MESSAGE #n";
4636 * otherwise, print line n relative to screen 4,
4637 * the line number may be negative.
4638 * Uses .LINE, but counter-adjusts to be relative to the real drive 0.
4640 FCC 'MESSAG' ; 'MESSAGE'
4643 MESS FDB DOCOL,WARN,AT,ZBRAN
4649 FDB OFSET,AT,BSCR,SLASH,SUB,DLINE,BRAN
4653 FCC 'err # ' ; 'err # '
4659 * Begin interpretation of screen (block) n.
4660 * See also ARROW, SEMIS, and NULL.
4662 FCC 'LOA' ; 'LOAD' : input:scr #
4665 LOAD FDB DOCOL,BLK,AT,TOR,IN,AT,TOR,ZERO,IN,STORE
4666 FDB BSCR,STAR,BLK,STORE
4667 FDB INTERP,FROMR,IN,STORE,FROMR,BLK,STORE
4672 * Continue interpreting source code on the next screen.
4677 ARROW FDB DOCOL,QLOAD,ZERO,IN,STORE,BSCR
4678 FDB BLK,AT,OVER,MOD,SUB,BLK,PSTORE
4683 * ######>> screen 63 <<
4684 * The next 4 subroutines are machine dependent, and are
4685 * called by words 13 through 16 in the dictionary.
4687 * ======>> 182 << code for EMIT
4688 * ( --- ) No parameter stack effect.
4689 * Interfaces directly with ROM. Expects output character in D (therefore, B).
4690 * Output using rom CHROUT: redirectable to a printer on Coco.
4691 * Outputs the character on stack (low byte of 1 bit word/cell).
4692 PEMIT PSHS Y,U,DP ; Save everything important! (For good measure, only.)
4693 TFR B,A ; Coco ROM wants it in A.
4695 TFR B,DP ; Give the ROM its direct page.
4696 JSR [$A002] ; Output the character in A.
4698 * PEMIT STB N save B
4701 * BITB #2 check ready bit
4702 * BEQ PEMIT+4 if not ready for more data
4705 * STB IOSTAT-UORIG,X
4706 * LDB N recover B & X
4708 * RTS only A register may change
4709 * PEMIT JMP $E1D1 for MIKBUG
4710 * PEMIT FCB $3F,$11,$39 for PROTO
4711 * PEMIT JMP $D286 for Smoke Signal DOS
4713 * ======>> 183 << code for KEY
4714 * ( --- ) No parameter stack effect.
4715 * Returns character or break flag in D, since this interfaces with Coco ROM.
4716 * Wait for key from POLCAT on Coco.
4717 * Returns the character code for the key pressed.
4718 PKEY PSHS Y,U,DP ; Must save everything important for this one.
4719 LDA #$CF ; a cursor of sorts
4731 PKEYR CLRB ; for the break flag, shares code with PQTER
4734 COMB ; for the break flag
4735 PKEYGT EXG A,B ; Leave it in D for return.
4736 PULS Y,U,DP,PC ; Shares exit with PQTER
4742 * BCC PKEY+4 no incoming data yet
4744 * ANDA #$7F strip parity bit
4746 * STB IOSTAT+1-UORIG,X
4750 * PKEY JMP $E1AC for MIKBUG
4751 * PKEY FCB $3F,$14,$39 for PROTO
4752 * PKEY JMP $D289 for Smoke Signal DOS
4754 * ######>> screen 64 <<
4755 * ======>> 184 << code for ?TERMINAL
4756 * ( --- f ) Should change this to no stack effect.
4757 * check break key using POLCAT
4758 * Returns a flag to tell whether the break key was pressed or not.
4762 JSR [$A000] ; Look but don't wait.
4764 * PQTER LDA ACIAC Test for 'break' condition
4765 * ANDA #$11 mask framing error bit and
4768 * LDA ACIAD clear input buffer
4775 * ======>> 185 << code for CR
4776 * ( --- ) No stack effect.
4777 * Interfaces directly with ROM.
4778 * For Coco just output a CR.
4779 * Also subject to redirection in Coco BASIC ROM.
4781 BRA PEMIT ; Just steal the code.
4782 * PCR LDA #$D carriage return
4788 * LDB XDELAY+1-UORIG,X
4790 * BMI PQTER2 return if minus
4791 * PSHS B ; save counter
4792 * BSR PEMIT print RUBOUTs to delay.....
4799 * ######>> screen 66 <<
4802 * Query the disk, I suppose.
4803 * Not sure what the model had in mind for this stub.
4805 FCC '?DIS' ; '?DISC'
4811 * ######>> screen 67 <<
4814 * Write one block of data to disk.
4815 * Parameters unspecified in model. Stub in model.
4817 FCC 'BLOCK-WRIT' ; 'BLOCK-WRITE'
4823 * ######>> screen 68 <<
4826 * Read one block of data from disk.
4827 * Parameters unspecified in model. Stub in model.
4829 FCC 'BLOCK-REA' ; 'BLOCK-READ'
4835 *The next 3 words are written to create a substitute for disc
4836 * mass memory,located between $3210 & $3FFF in ram.
4843 FDB MEMEND a system dependent equate at front
4851 FDB MEMTOP ( $3FFF or $7FFF in this version )
4853 * ######>> screen 69 <<
4855 * ( buffer sector f --- )
4856 * Read or Write the specified (absolute -- ignores OFFSET) sector
4857 * from or to the specified buffer.
4858 * A zero flag specifies write,
4859 * non-zero specifies read.
4860 * Sector is an unsigned integer,
4861 * buffer is the buffer's address.
4862 * Will need to use the CoCo ROM disk routines.
4863 * For now, provides a virtual disk in RAM.
4868 RW FDB DOCOL,TOR,BBUF,STAR,LO,PLUS,DUP,HI,GREAT,ZBRAN
4872 FCC ' Range ?' ; ' Range ?'
4882 * LDY $C006 control table
4883 * LDX #DROFFS+7 ; This is BIF's table of drive sizes.
4885 * RWD SUBD ,X++ sectors
4887 * BVC RWR table end?
4891 * RWR ADDD ,--X back one
4894 * LDD #18 sectors/track
4904 * PULS D table entry
4917 * JSR [$C004] ROM handles timeout
4918 * PULS Y,U,DP if IRQ enabled
4921 * LDB 6,X coco status
4931 * ######>> screen 72 <<
4933 * ( --- ) compiling P
4934 * ( --- adr ) interpreting
4936 * Parse a symbol name from input and search the dictionary for it, per -FIND;
4937 * compile the address as a literal if compiling,
4938 * otherwise just push it.
4942 TICK FDB DOCOL,DFIND,ZEQU,ZERO,QERR,DROP,LITER
4946 * ( --- ) { FORGET name } input
4947 * Parse out name of definition to FORGET to, -DFIND it,
4948 * then lop it and everything that follows out of the dictionary.
4949 * In fig Forth, CURRENT and CONTEXT have to be the same to FORGET.
4951 FCC 'FORGE' ; 'FORGET'
4954 FORGET FDB DOCOL,CURENT,AT,CONTXT,AT,SUB,LIT8
4956 FDB QERR,TICK,DUP,FENCE,AT,LESS,LIT8
4958 FDB QERR,DUP,ZERO,PORIG,GREAT,LIT8
4960 FDB QERR,DUP,NFA,DICTPT,STORE,LFA,AT,CONTXT,AT,STORE
4963 * ######>> screen 73 <<
4966 * Calculate a back reference from HERE and compile it.
4971 * BACK FDB DOCOL,HERE,SUB,COMMA
4972 BACK FDB DOCOL,HERE,NATP,SUB,COMMA
4977 * typical use: BEGIN code-loop test UNTIL
4978 * typical use: BEGIN code-loop AGAIN
4979 * typical use: BEGIN code-loop test WHILE code-true REPEAT
4980 * ( --- adr n ) compile time P,C
4981 * Push HERE for BACK reference for general (non-counting) loops,
4982 * with BEGIN construct flag.
4983 * A better flag: $4245 (ASCII for 'BE').
4985 FCC 'BEGI' ; 'BEGIN'
4988 BEGIN FDB DOCOL,QCOMP,HERE,ONE ; ONE is a flag for BEGIN loops.
4993 * typical use: test IF code-true ELSE code-false ENDIF
4994 * ENDIF is just a sort of intersection piece,
4995 * marking where execution resumes after both branches.
4996 * ( adr n --- ) compile time
4997 * Check the mark and resolve the IF.
4998 * A better flag: $4846 (ASCII for 'IF').
5000 FCC 'ENDI' ; 'ENDIF'
5003 ENDIF FDB DOCOL,QCOMP,TWO,QPAIRS,HERE ; This TWO is a flag for IF.
5004 FDB OVER,NATP,SUB,SWAP,STORE
5009 * typical use: test IF code-true ELSE code-false ENDIF
5016 THEN FDB DOCOL,ENDIF
5020 * ( limit index --- ) runtime
5021 * typical use: DO code-loop LOOP
5022 * typical use: DO code-loop increment +LOOP
5023 * Counted loop, index is initial value of index.
5024 * Will loop until index equals (positive going)
5025 * or passes (negative going) limit.
5026 * ( --- adr n ) compile time P,C
5027 * Compile (DO), push HERE for BACK reference,
5028 * and push DO control construct flag.
5029 * A better flag: $444F (ASCII for 'DO').
5034 DO FDB DOCOL,COMPIL,XDO,HERE,THREE ; THREE is a flag for DO loops.
5039 * typical use: DO code-loop LOOP
5040 * Increments the index by one and branches back to beginning of loop.
5041 * Will loop until index equals limit.
5042 * ( adr n --- ) compile time P,C
5043 * Check the mark and compile (LOOP), fill in BACK reference.
5044 * A better flag: $444F (ASCII for 'DO').
5049 LOOP FDB DOCOL,THREE,QPAIRS,COMPIL,XLOOP,BACK ; THREE for DO loops.
5054 * typical use: DO code-loop increment +LOOP
5055 * Increments the index by n and branches back to beginning of loop.
5056 * Will loop until index equals (positive going)
5057 * or passes (negative going) limit.
5058 * ( adr n --- ) compile time P,C
5059 * Check the mark and compile (+LOOP), fill in BACK reference.
5060 * A better flag: $444F (ASCII for 'DO').
5062 FCC '+LOO' ; '+LOOP'
5065 PLOOP FDB DOCOL,THREE,QPAIRS,COMPIL,XPLOOP,BACK ; THREE for DO loops.
5070 * typical use: BEGIN code-loop test UNTIL
5071 * Will loop until UNTIL tests true.
5072 * ( adr n --- ) compile time P,C
5073 * Check the mark and compile (0BRANCH), fill in BACK reference.
5074 * A better flag: $4245 (ASCII for 'BE').
5076 FCC 'UNTI' ; 'UNTIL' : ( same as END )
5079 UNTIL FDB DOCOL,ONE,QPAIRS,COMPIL,ZBRAN,BACK ; ONE for BEGIN loops.
5082 * ######>> screen 74 <<
5085 * typical use: BEGIN code-loop test END
5097 * typical use: BEGIN code-loop AGAIN
5099 * (or until something uses R> DROP to force the current definition to die,
5100 * or perhaps ABORT or ERROR or some such other drastic means stops things).
5101 * ( adr n --- ) compile time P,C
5102 * Check the mark and compile (0BRANCH), fill in BACK reference.
5103 * A better flag: $4245 (ASCII for 'BE').
5105 FCC 'AGAI' ; 'AGAIN'
5108 AGAIN FDB DOCOL,ONE,QPAIRS,COMPIL,BRAN,BACK ; ONE for BEGIN loops.
5113 * typical use: BEGIN code-loop test WHILE code-true REPEAT
5114 * Will loop until WHILE tests false, skipping code-true on end.
5115 * REPEAT marks where execution resumes after the WHILE find a false flag.
5116 * ( aadr1 n1 adr2 n2 --- ) compile time P,C
5117 * Check the marks for WHILE and BEGIN,
5118 * compile BRANCH and BACK fill adr1 reference,
5119 * FILL-IN 0BRANCH reference at adr2.
5120 * Better flags: $4245 (ASCII for 'BE') and $5747 (ASCII for 'WH').
5122 FCC 'REPEA' ; 'REPEAT'
5125 REPEAT FDB DOCOL,TOR,TOR,AGAIN,FROMR,FROMR ; ONE for BEGIN loops.
5126 FDB TWO,SUB,ENDIF ; TWO is for IF, 4 is for WHILE.
5131 * typical use: test IF code-true ELSE code-false ENDIF
5132 * Will pass execution to the true part on a true flag
5133 * and to the false part on a false flag.
5134 * ( --- adr n ) compile time P,C
5135 * Compile a 0BRANCH and dummy offset
5136 * and push IF reference to fill in and
5137 * IF control construct flag.
5138 * A better flag: $4946 (ASCII for 'IF').
5143 IF FDB DOCOL,COMPIL,ZBRAN,HERE,ZERO,COMMA,TWO ; TWO is a flag for IF.
5148 * typical use: test IF code-true ELSE code-false ENDIF
5149 * ELSE is just a sort of intersection piece,
5150 * marking where execution resumes on a false branch.
5151 * ( adr1 n --- adr2 n ) compile time P,C
5153 * compile BRANCH with dummy offset,
5154 * resolve IF reference,
5155 * and leave reference to BRANCH for ELSE.
5156 * A better flag: $4946 (ASCII for 'IF').
5161 ELSE FDB DOCOL,TWO,QPAIRS,COMPIL,BRAN,HERE
5162 FDB ZERO,COMMA,SWAP,TWO,ENDIF,TWO ; TWO is a flag for IF.
5167 * typical use: BEGIN code-loop test WHILE code-true REPEAT
5168 * Will loop until WHILE tests false, skipping code-true on end.
5169 * ( --- adr n ) compile time P,C
5170 * Compile 0BRANCH with dummy offset (using IF),
5171 * push WHILE reference.
5172 * BEGIN flag will sit underneath this.
5173 * Better flags: $4245 (ASCII for 'BE') and $5747 (ASCII for 'WH').
5175 FCC 'WHIL' ; 'WHILE'
5178 WHILE FDB DOCOL,IF,TWOP ; TWO is a flag for IF, 4 is for WHILE.
5181 * ######>> screen 75 <<
5184 * EMIT count spaces, for non-zero, non-negative counts.
5186 FCC 'SPACE' ; 'SPACES'
5189 SPACES FDB DOCOL,ZERO,MAX,DDUP,ZBRAN
5192 SPACE2 FDB SPACE,XLOOP
5198 * Initialize HLD for converting a double integer.
5199 * Stores the PAD address in HLD.
5204 BDIGS FDB DOCOL,PAD,HLD,STORE
5208 * ( d --- string length )
5209 * Terminate numeric conversion,
5210 * drop the number being converted,
5211 * leave the address of the conversion string and the length, ready for TYPE.
5216 EDIGS FDB DOCOL,DROP,DROP,HLD,AT,PAD,OVER,SUB
5221 * Put sign of n (as a flag) at the head of the conversion string.
5222 * Drop the sign flag.
5227 SIGN FDB DOCOL,ROT,ZLESS,ZBRAN
5236 * Generate next most significant digit in the conversion BASE,
5237 * putting the digit at the head of the conversion string.
5241 DIG FDB DOCOL,BASE,AT,MSMOD,ROT,LIT8
5255 * Convert d to a numeric string using # until the result is zero.
5256 * Leave the double result on the stack for #> to drop.
5262 DIGS2 FDB DIG,OVER,OVER,OR,ZEQU,ZBRAN
5266 * ######>> screen 76 <<
5269 * Print n on the output device in the current conversion base,
5271 * right aligned in a field at least width wide.
5276 DOTR FDB DOCOL,TOR,STOD,FROMR,DDOTR
5281 * Print d on the output device in the current conversion base,
5283 * right aligned in a field at least width wide.
5288 DDOTR FDB DOCOL,TOR,SWAP,OVER,DABS,BDIGS,DIGS,SIGN
5289 FDB EDIGS,FROMR,OVER,SUB,SPACES,TYPE
5294 * Print d on the output device in the current conversion base,
5296 * in free format with trailing space.
5301 DDOT FDB DOCOL,ZERO,DDOTR,SPACE
5306 * Print n on the output device in the current conversion base,
5308 * in free format with trailing space.
5312 DOT FDB DOCOL,STOD,DDOT
5317 * Print signed word at adr, per DOT.
5321 QUEST FDB DOCOL,AT,DOT
5324 * ######>> screen 77 <<
5327 * Print out screen n as a field of ASCII,
5328 * with line numbers in decimal.
5329 * Needs a console more than 70 characters wide.
5334 LIST FDB DOCOL,DEC,CR,DUP,SCR,STORE,PDOTQ
5340 LIST2 FDB CR,I,THREE
5341 FDB DOTR,SPACE,I,SCR,AT,DLINE,XLOOP
5348 * Print comment lines (line 0, and line 1 if C/L < 41) of screens
5349 * from start to end.
5350 * Needs a console more than 70 characters wide.
5352 FCC 'INDE' ; 'INDEX'
5355 INDEX FDB DOCOL,CR,ONEP,SWAP,XDO
5356 INDEX2 FDB CR,I,THREE
5357 FDB DOTR,SPACE,ZERO,I,DLINE
5367 * List a printer page full of screens.
5368 * Line and screen number are in current base.
5369 * Needs a console more than 70 characters wide.
5371 FCC 'TRIA' ; 'TRIAD'
5374 TRIAD FDB DOCOL,THREE,SLASH,THREE,STAR
5375 FDB THREE,OVER,PLUS,SWAP,XDO
5377 FDB LIST,QTERM,ZBRAN
5387 * ######>> screen 78 <<
5390 * Alphabetically list the definitions in the current vocabulary.
5391 * Expects to output to printer, not TRS80 Color Computer screen.
5393 FCC 'VLIS' ; 'VLIST'
5396 VLIST FDB DOCOL,LIT8
5398 FDB OUT,STORE,CONTXT,AT,AT
5399 VLIST1 FDB OUT,AT,COLUMS,AT,LIT8
5403 FDB CR,ZERO,OUT,STORE
5404 VLIST2 FDB DUP,IDDOT,SPACE,SPACE,PFA,LFA,AT
5405 FDB DUP,ZEQU,QTERM,OR,ZBRAN
5410 * Need some utility stuff that isn't in the fig FORTH:
5412 * Emit dot if c is less than blank, else emit c
5414 FCC 'BEMI' ; 'BEMIT'
5418 FDB DUP,BL,LESS,ZBRAN
5426 * Output n in hexadecimal field width.
5432 FDB BASE,AT,TOR,HEX,DOTR,FROMR,BASE,STORE
5436 * Dump a line of 4 bytes in memory, in hex and as characters.
5438 FCC 'BLIN' ; 'BLINE'
5445 BLINEX FDB I,CAT,THREE,XDOTR,XLOOP
5451 BLINEC FDB I,CAT,BEMIT,XLOOP
5456 * Dump 4 byte lines from start to end.
5458 FCC 'BDUM' ; 'BDUMP'
5476 * Mostly for place holding (fig Forth).
5481 NOOP FDB NEXT a useful no-op
5482 ZZZZ FDB 0,0,0,0,0,0,0,0 end of rom program
5485 * These things, up through the lable 'REND', are overwritten
5486 * at time of cold load and should have the same contents
5489 * This can be moved whereever the bottom of the
5490 * user's dictionary is going to be put.
5493 FCC 'FORT' ; 'FORTH'
5496 FORTH FDB DODOES,DOVOC,$81A0,TASK-7
5499 FCC "(C) Forth Interest Group, 1979"
5505 TASK FDB DOCOL,SEMIS
5507 REND EQU * ( first empty location in dictionary )