+; mainargs.s
;
; Ullrich von Bassewitz, 2003-03-07
-;
-; Setup arguments for main.
; Based on code from Stefan A. Haubenthal, <polluks@web.de>
+; 2003-05-18, Greg King
;
+; 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" and "rem" are entokenned; the args. are not. Leading spaces are
+; ignored; trailing spaces are included -- unless the argument was quoted.
- .constructor initmainargs, 24
- .import __argc, __argv
-
- .include "c64.inc"
-
-;---------------------------------------------------------------------------
-; Setup arguments for main
-
-.proc initmainargs
-
-; Setup a pointer to our argv vector
-
- lda #<argv
- sta __argv
- lda #>argv
- sta __argv+1
-
-; Save the last filename as argument #0. Since the buffer we're copying into
-; is zeroed out, we don't need to add a NUL character.
-
- ldy FNAM_LEN
- cpy #16+1
- bcc L0
- ldy #16 ; Limit the length
-L0: dey
-L1: lda (FNAM),y
- sta argv0,y
- dey
- bpl L1
- inc __argc ; __argc = 1
-
-; Find argument in BASIC buffer, if found, use it as arg #1
-
- ldy #0
-L2: lda $200,y
- beq L9
- iny
- cmp #$8F ; REM token
- bne L2
- sty argv+2 ; Store offset
- ldy #>$200
- sty argv+3
- inc __argc ; argc = 2
-
-; Done
-
-L9: rts
-
-.endproc
-
+; TO-DO:
+; - The "file-name" might be a path-name; don't copy the directory-components.
+; - Add a control-character quoting mechanism.
-;---------------------------------------------------------------------------
-; Data
+ .constructor initmainargs, 24
+ .import __argc, __argv
-.data
+ .include "c64.inc"
-argv: .word argv0 ; Pointer to program name
- .word $0000 ; Optional second argument
- .word $0000 ; Last vector must always be NULL
+; 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')
-.bss
-argv0: .res 17 ; Program name
+REM = $8f ; BASIC token-code
+NAME_LEN = 16 ; maximum length of command-name
+; 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
+
+; 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)
+
+; (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];
+; char* argv[MAXARGS+1]={name};
+;
+ .bss
+quoted: .res 1, %00000000
+name: .res NAME_LEN + 1
+argv: .res (MAXARGS + 1) * 2
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