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; mainargs.s
;
; 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
; 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.
;
; 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
.include "vic20.inc"
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"
initmainargs:
; Assume that the program was loaded, a moment ago, by the traditional LOAD
; statement. Save the "most-recent filename" as argument #0.
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 ; 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
.segment "INIT"
term: .res 1
name: .res NAME_LEN + 1
.data
; char* argv[MAXARGS+1]={name};
argv: .addr name
.res MAXARGS * 2
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