; Command-lines look like these lines:
;
-; call2048
-; call2048 : rem
-; call2048:rem arg1 " arg 2 is quoted " arg3 "" arg5
+; call2051
+; call2051 : rem
+; call2051:rem arg1 " arg 2 is quoted " arg3 "" arg5
;
-; "call" and "rem" are entokenned; the args. are not. Leading and trailing
+; "call" and "rem" are entokenned; the args. are not. Leading and trailing
; spaces outside of quotes are ignored.
; TO-DO:
; Add a control-character quoting mechanism.
- .constructor initmainargs, 24
- .import __argc, __argv, __dos_type
+ .constructor initmainargs, 24
+ .import __argc, __argv, __dos_type
- .include "zeropage.inc"
- .include "apple2.inc"
+ .include "zeropage.inc"
+ .include "apple2.inc"
; Maximum number of arguments allowed in the argument table.
; (An argument contains a comma, at least.)
MAXARGS = 10
+; ProDOS stores the filename in the second half of BASIC's input buffer, so
+; there are 128 characters left. At least 7 characters are necessary for the
+; CALLxxxx:REM so 121 characters may be used before overwriting the ProDOS
+; filename. As we don't want to put further restrictions on the command-line
+; length we reserve those 121 characters terminated by a zero.
+
+BUF_LEN = 122
+
BASIC_BUF = $200
FNAM_LEN = $280
FNAM = $281
-REM = $B2 ; BASIC token-code
+REM = $B2 ; BASIC token-code
; Get possible command-line arguments. Goes into the special INIT segment,
-; which may be reused after the startup code is run
+; which may be reused after the startup code is run.
.segment "INIT"
initmainargs:
; Assume that the program was loaded, a moment ago, by the traditional BLOAD
-; statement of BASIC.SYSTEM. Save the "most-recent filename" as argument #0.
+; statement of BASIC.SYSTEM. Save the filename as argument #0 if available.
- ldx __dos_type ; No ProDOS -> argv[0] = ""
- beq :+
+ ldx __dos_type ; No ProDOS -> argv[0] = ""
+ beq :+
; Terminate the filename with a zero to make it a valid C string.
- ldx FNAM_LEN
-: lda #$00
- sta FNAM,x
+ ldx FNAM_LEN
+: lda #$00
+ sta FNAM,x
- inc __argc ; argc always is equal to, at least, 1
+ inc __argc ; argc always is equal to, at least, 1
; Find the "rem" token.
- ldx #$00
-: lda BASIC_BUF,x
- beq done ; No "rem" -> no args
+ ldx #$00
+: lda BASIC_BUF,x
+ beq done ; No "rem" -> no args
inx
- cmp #REM
- bne :-
- ldy #$01 * 2 ; Start with argv[1]
-
-; Find the next argument.
-
-next: lda BASIC_BUF,x
- beq done
+ cmp #REM
+ bne :-
+
+; If a clock is present it is called by ProDOS on file operations. On machines
+; with a slot-based clock (like the Thunder Clock) the clock firmware places
+; the current date in BASIC's input buffer. Therefore we have to create a copy
+; of the command-line in a different buffer before the original is potentially
+; destroyed.
+
+ ldy #$00
+: lda BASIC_BUF,x
+ sta buffer,y
inx
- cmp #' ' ; Skip leading spaces
- beq next
+ iny
+ cpy #BUF_LEN - 1 ; Keep the terminating zero intact
+ bcc :-
+
+; Start processing the arguments.
+
+ ldx #$00
+ ldy #$01 * 2 ; Start with argv[1]
+
+; Find the next argument. Stop if the end of the string or a character with the
+; hibit set is reached. The later is true if the string isn't already parsed by
+; BASIC (as expected) but is a still unprocessed input string. In this case the
+; string isn't the expected command-line at all. We found this out the hard way
+; by BRUNing the program with ProDOS on a machine with a slot-based clock (like
+; the Thunder Clock). ProDOS called the clock firmware which places the current
+; date as BASIC input string with hibits set in the input buffer. While looking
+; for the REM token we stumbled across the first '2' character ($32+$80 = $B2)
+; and interpreted the rest of the date as a spurious command-line parameter.
+
+next: lda buffer,x
+ beq done
+ bmi done
+ 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.
- 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 tmp1 ; Set end of argument marker
+ cmp #'"' ; Is the argument quoted?
+ beq :+ ; Jump if so
+ dex ; Reset pointer to first argument character
+ lda #' ' ; A space ends the argument
+: sta tmp1 ; 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.
+; Now store a pointer to the argument into the next slot.
- txa ; Get low byte
- sta argv,y ; argv[y] = &arg
+ txa ; Get low byte
+ clc
+ adc #<buffer
+ sta argv,y ; argv[y] = &arg
iny
- lda #>BASIC_BUF
- sta argv,y
+ lda #$00
+ adc #>buffer
+ sta argv,y
iny
- inc __argc ; Found another arg
+ inc __argc ; Found another arg
-; Search for the end of the argument
+; Search for the end of the argument.
-argloop:lda BASIC_BUF,x
- beq done
+: lda buffer,x
+ beq done
inx
- cmp tmp1
- bne argloop
+ cmp tmp1
+ bne :-
; 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 #$00
- sta BASIC_BUF-1,x
+ lda #$00
+ sta buffer-1,x
-; Check if the maximum number of command line arguments is reached. If not,
+; 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
+ 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
+ ldx #>argv
+ sta __argv
+ stx __argv+1
rts
; This array is zeroed before initmainargs is called.
.data
-argv: .addr FNAM
- .res MAXARGS * 2
+argv: .addr FNAM
+ .res MAXARGS * 2
+
+ .bss
+
+buffer: .res BUF_LEN
\ No newline at end of file
projects / cc65 / blobdiff