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Add parsing routines for bare commands and REM statements
author William Astle <lost@l-w.ca>
date Tue, 09 Jan 2024 22:47:11 -0700
parents ac183a519439
children d5886daa4f65
comparison
equal deleted inserted replaced
126:ac183a519439 127:527212870064
29 parse_error puls u ; restore original free memory location - deallocate any encoding 29 parse_error puls u ; restore original free memory location - deallocate any encoding
30 stu freestart 30 stu freestart
31 ldu parse_tokenst ; get start location we started parsing the token at 31 ldu parse_tokenst ; get start location we started parsing the token at
32 rts ; return error condition 32 rts ; return error condition
33 parse0 ldx #parsetab_cmd ; point to jump table for token type handler 33 parse0 ldx #parsetab_cmd ; point to jump table for token type handler
34 cmpb #token_stmtsep ; is it a statement separator?
35 beq parse_nextstmt ; brif so - we can just skip it
34 parse1 cmpb ,x ; did we match a valid command token? 36 parse1 cmpb ,x ; did we match a valid command token?
35 beq parse3 ; brif so 37 beq parse3 ; brif so
36 leax 3,x ; move to next entry 38 leax 3,x ; move to next entry
37 cmpx #parsetab_cmde ; end of table? 39 cmpx #parsetab_cmde ; end of table?
38 blo parse1 ; brif not 40 blo parse1 ; brif not
39 parse2 ldb #err_sn ; flag syntax error 41 parse2 ldb #err_sn ; flag syntax error
40 bra parse_error ; and return the error 42 bra parse_error ; and return the error
41 parse3 jsr [1,x] ; call the handler 43 parse3 jsr [1,x] ; call the handler
42 bcs parse_error ; brif the handler indicated error 44 bcs parse_error ; brif the handler indicated error
43 jsr parse_curtoken ; get the token we terminated on 45 bsr parse_curtoken ; fetch the token we left off on
44 cmpb #token_eot ; end of input? 46 cmpb #token_eot ; end of input?
45 bne parse4 ; brif not 47 bne parse4 ; brif not
46 ldb #bc_eol ; stash an end of line op 48 ldb #bc_eol ; stash an end of line op
47 bsr parse_write 49 bsr parse_write
48 bcs parse_error ; brif we errored out writing to the result (OM?) 50 bcs parse_error ; brif we errored out writing to the result (OM?)
131 cmpa #'z ; is it still lower case alpha? 133 cmpa #'z ; is it still lower case alpha?
132 bhi parse_toupper0 ; brif not 134 bhi parse_toupper0 ; brif not
133 suba #0x20 ; adjust to upper case alpha 135 suba #0x20 ; adjust to upper case alpha
134 parse_toupper0 rts ; Z only set here if input was zero entering from parse_nextcharu 136 parse_toupper0 rts ; Z only set here if input was zero entering from parse_nextcharu
135 parse_number jmp parse_tokerr 137 parse_number jmp parse_tokerr
138 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
139 ; Parse a statement that consists of just the command token
140 parse_cmdsingle equ parse_write ; just write the token out and bail
141 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
142 ; Parse a REM or ' statement. We just copy the comment out after the REM or ' token.
143 parse_rem jsr parse_write ; write the token/character out
144 ldb ,y+ ; get next input character
145 bne parse_rem ; brif not at the end of the input
146 ldb #token_eot ; flag end of input for mainline parser
147 stb parse_curtok
148 rts ; return, pass back the C result from parse_write
136 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; 149 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
137 ; This routine parses tokens using the table at parse_wordtab. The table is structured as follows: 150 ; This routine parses tokens using the table at parse_wordtab. The table is structured as follows:
138 ; 151 ;
139 ; * two bytes which contain the length of the table less the two bytes for this length value 152 ; * two bytes which contain the length of the table less the two bytes for this length value
140 ; * a sequence of entries consisting of a single byte matching character and a token code followed 153 ; * a sequence of entries consisting of a single byte matching character and a token code followed
338 parse_tokendefp then ; THEN 351 parse_tokendefp then ; THEN
339 parse_tokendefp to ; TO 352 parse_tokendefp to ; TO
340 parse_tokendefp sub ; SUB 353 parse_tokendefp sub ; SUB
341 parse_tokendefp as ; AS 354 parse_tokendefp as ; AS
342 355
343 parse_tokendefc remabbr,parse_noop,list_noop,exec_noop ; abbreviated REM (') 356 parse_tokendefc remabbr,parse_rem,list_noop,exec_noop ; abbreviated REM (')
344 parse_tokendefc rem,parse_noop,list_noop,exec_noop ; REM 357 parse_tokendefc rem,parse_rem,list_noop,exec_noop ; REM
345 parse_tokendefc return,parse_noop,parse_noop,parse_noop ; RETURN 358 parse_tokendefc return,parse_cmdsingle,parse_noop,parse_noop ; RETURN
346 parse_tokendefc run,parse_noop,parse_noop,parse_noop ; RUN 359 parse_tokendefc run,parse_noop,parse_noop,parse_noop ; RUN
347 parse_tokendefc data,parse_noop,parse_noop,parse_noop ; DATA 360 parse_tokendefc data,parse_noop,parse_noop,parse_noop ; DATA
348 parse_tokendefc end,parse_noop,parse_noop,parse_noop ; END 361 parse_tokendefc end,parse_cmdsingle,parse_noop,parse_noop ; END
349 parse_tokendefc stop,parse_noop,parse_noop,parse_noop ; STOP 362 parse_tokendefc stop,parse_cmdsingle,parse_noop,parse_noop ; STOP
350 parse_tokendefc let,parse_noop,parse_noop,parse_noop ; LET 363 parse_tokendefc let,parse_noop,parse_noop,parse_noop ; LET
351 parse_tokendefc list,parse_noop,parse_noop,parse_noop ; LIST 364 parse_tokendefc list,parse_noop,parse_noop,parse_noop ; LIST
352 parse_tokendefc new,parse_noop,parse_noop,parse_noop ; NEW 365 parse_tokendefc new,parse_cmdsingle,parse_noop,parse_noop ; NEW
353 parse_tokendefc print,parse_noop,parse_noop,parse_noop ; PRINT 366 parse_tokendefc print,parse_noop,parse_noop,parse_noop ; PRINT
354 parse_tokendefc pop,parse_noop,parse_noop,parse_noop ; POP 367 parse_tokendefc pop,parse_cmdsingle,parse_noop,parse_noop ; POP
355 parse_tokendefc goto,parse_noop,parse_noop,parse_noop ; GOTO 368 parse_tokendefc goto,parse_noop,parse_noop,parse_noop ; GOTO
356 parse_tokendefc gosub,parse_noop,parse_noop,parse_noop ; GOSUB 369 parse_tokendefc gosub,parse_noop,parse_noop,parse_noop ; GOSUB
357 parse_tokendefc go,parse_noop,parse_noop,parse_noop ; GO 370 parse_tokendefc go,parse_noop,parse_noop,parse_noop ; GO
358 371
359 parse_tokendeff asc,parse_noop,parse_noop,parse_noop ; ASC() 372 parse_tokendeff asc,parse_noop,parse_noop,parse_noop ; ASC()