; Ullrich von Bassewitz, 2003-03-07
; Based on code from Stefan A. Haubenthal, <polluks@web.de>
; 2003-05-18, Greg King
+; 2004-04-28, 2005-02-26, Ullrich von Bassewitz
;
; Scan a group of arguments that are in BASIC's input-buffer.
; Build an array that points to the beginning of each argument.
; Send, to main(), that array and the count of the arguments.
-
+;
; Command-lines look like these lines:
;
; run
-; run : rem no arguments because no comma!
-; run:rem,arg1," arg 2" , arg 3 ,, arg5, ...
+; run : rem
+; run:rem arg1 " arg 2 is quoted " arg3 "" arg5
+;
+; "run" and "rem" are entokenned; the args. are not. Leading and trailing
+; spaces outside of quotes are ignored.
;
-; "run" and "rem" are entokenned; the args. are not. Leading spaces are
-; ignored; trailing spaces are included -- unless the argument was quoted.
-
; TO-DO:
; - The "file-name" might be a path-name; don't copy the directory-components.
; - Add a control-character quoting mechanism.
- .constructor initmainargs, 24
- .import __argc, __argv
+ .constructor initmainargs, 24
+ .import __argc, __argv
- .include "c64.inc"
+ .include "c64.inc"
-; Maximum number of arguments allowed in the argument table.
-; (An argument contains a comma, at least.)
-;
-MAXARGS = BASIC_BUF_LEN - 2 ; (don't count REM and terminating '\0')
-REM = $8f ; BASIC token-code
-NAME_LEN = 16 ; maximum length of command-name
+MAXARGS = 10 ; Maximum number of arguments allowed
+REM = $8f ; BASIC token-code
+NAME_LEN = 16 ; Maximum length of command-name
+
+; Get possible command-line arguments. Goes into the special ONCE segment,
+; which may be reused after the startup code is run
+
+.segment "ONCE"
-; Get possible command-line arguments.
-;
initmainargs:
; Assume that the program was loaded, a moment ago, by the traditional LOAD
; statement. Save the "most-recent filename" as argument #0.
-; Because the buffer, that we're copying into, was zeroed out,
-; we don't need to add a NUL character.
-;
- ldy FNAM_LEN
- cpy #NAME_LEN + 1
- bcc L1
- ldy #NAME_LEN - 1 ; limit the length
-L0: lda (FNAM),y
- sta name,y
-L1: dey
- bpl L0
- lda #<name
- ldx #>name
- sta argv
- stx argv + 1
- inc __argc ; argc always is equal to, at least, 1
+
+ lda #0 ; The terminating NUL character
+ ldy FNAM_LEN
+ cpy #NAME_LEN + 1
+ bcc L1
+ ldy #NAME_LEN ; Limit the length
+ bne L1 ; Branch always
+L0: lda (FNAM),y
+L1: sta name,y
+ dey
+ bpl L0
+ inc __argc ; argc always is equal to, at least, 1
; Find the "rem" token.
-;
- ldx #0
-L2: lda BASIC_BUF,x
- beq done ; no "rem," no args.
- inx
- cmp #REM
- bne L2
- ldy #1 * 2
-
-; Find the next argument.
-;
-next: lda BASIC_BUF,x
- beq done
- inx
- cmp #',' ; look for argument-list separator
- bne next
- lda #$00
- sta BASIC_BUF-1,x ; make the previous arg. be a legal C string
- inc __argc ; found another arg.
-
-L4: lda BASIC_BUF,x
- beq point ; zero-length argument
- inx
- cmp #' '
- beq L4 ; skip leading spaces
-
- cmp #'"' ; is argument quoted?
- beq L5
- dex ; no, don't skip over character
- clc ; (quotation-mark sets flag)
-L5: ror quoted ; save it
-
-; BASIC's input-buffer starts at the beginning of a RAM page.
-; So, we don't need to add the offset -- just store it.
-;
-point: txa
- sta argv,y ; argv[y]= &arg
- iny
- lda #>BASIC_BUF
- sta argv,y
- iny
-
- asl quoted ; is argument a string-literal?
- bcc next ; no, don't look for ending quotation-mark
-L7: lda BASIC_BUF,x
- beq done
- inx
- cmp #'"'
- bne L7
- lda #$00
- sta BASIC_BUF-1,x ; make this arg. be a legal C string
- beq next ;(bra)
+
+ ldx #0
+L2: lda BASIC_BUF,x
+ beq done ; No "rem," no args.
+ inx
+ cmp #REM
+ bne L2
+ ldy #1 * 2
+
+; Find the next argument
+
+next: lda BASIC_BUF,x
+ beq done ; End of line reached
+ inx
+ cmp #' ' ; Skip leading spaces
+ beq next
+
+; Found start of next argument. We've incremented the pointer in X already, so
+; it points to the second character of the argument. This is useful since we
+; will check now for a quoted argument, in which case we will have to skip this
+; first character.
+
+found: cmp #'"' ; Is the argument quoted?
+ beq setterm ; Jump if so
+ dex ; Reset pointer to first argument character
+ lda #' ' ; A space ends the argument
+setterm:sta term ; Set end of argument marker
+
+; Now store a pointer to the argument into the next slot. Since the BASIC
+; input buffer is located at the start of a RAM page, no calculations are
+; necessary.
+
+ txa ; Get low byte
+ sta argv,y ; argv[y]= &arg
+ iny
+ lda #>BASIC_BUF
+ sta argv,y
+ iny
+ inc __argc ; Found another arg
+
+; Search for the end of the argument
+
+argloop:lda BASIC_BUF,x
+ beq done
+ inx
+ cmp term
+ bne argloop
+
+; We've found the end of the argument. X points one character behind it, and
+; A contains the terminating character. To make the argument a valid C string,
+; replace the terminating character by a zero.
+
+ lda #0
+ sta BASIC_BUF-1,x
+
+; Check if the maximum number of command line arguments is reached. If not,
+; parse the next one.
+
+ lda __argc ; Get low byte of argument count
+ cmp #MAXARGS ; Maximum number of arguments reached?
+ bcc next ; Parse next one if not
; (The last vector in argv[] already is NULL.)
-;
-done: lda #<argv
- ldx #>argv
- sta __argv
- stx __argv + 1
- rts
-
-; These arrays are zeroed before initmainargs is called.
-; char name[16+1];
+
+done: lda #<argv
+ ldx #>argv
+ sta __argv
+ stx __argv + 1
+ rts
+
+.segment "INIT"
+
+term: .res 1
+name: .res NAME_LEN + 1
+
+.data
+
; char* argv[MAXARGS+1]={name};
-;
- .bss
-quoted: .res 1, %00000000
-name: .res NAME_LEN + 1
-argv: .res (MAXARGS + 1) * 2
+argv: .addr name
+ .res MAXARGS * 2
projects / cc65 / blobdiff