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cc65/libsrc/cbm610/mainargs.s

157 lines
4.5 KiB
ArmAsm

; mainargs.s
;
; 2003-03-07, Ullrich von Bassewitz,
; based on code from Stefan A. Haubenthal, <polluks@web.de>
; 2005-02-26, Ullrich von Bassewitz
; 2014-04-02, 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
; 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
.import sys_bank, restore_bank
.import sysp0:zp, ptr1:zp
.include "cbm610.inc"
.macpack generic
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 INIT segment,
; 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 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.
;
jsr sys_bank
ldy #FNAM
lda (sysp0),y ; Get file-name pointer from system bank
sta ptr1
iny
lda (sysp0),y
sta ptr1+1
iny ; FNAM_BANK
lda (sysp0),y
tax
ldy #FNAM_LEN
lda (sysp0),y
tay
stx IndReg ; Look for name in correct bank
cpy #NAME_LEN + 1
blt L1
ldy #NAME_LEN - 1 ; limit the length
L0: lda (ptr1),y
sta name,y
L1: dey
bpl L0
jsr restore_bank
inc __argc ; argc always is equal to at least 1
; Find a "rem" token.
;
ldx #0
L2: lda BASIC_BUF,x
bze done ; no "rem," no args.
inx
cmp #REM
bne L2
ldy #1 * 2
; Find the next argument.
;
next: lda BASIC_BUF,x
bze 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. That is useful because we
; will check now for a quoted argument; in which case, we will have to skip that
; 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.
;
txa ; Get low byte
add #<BASIC_BUF
sta argv,y ; argv[y]= &arg
lda #>0
adc #>BASIC_BUF
sta argv+1,y
iny
iny
inc __argc ; Found another arg
; Search for the end of the argument.
;
argloop:lda BASIC_BUF,x
bze 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?
blt 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];
; char* argv[MAXARGS+1]={name};
;
.bss
term: .res 1
name: .res NAME_LEN + 1
.data
argv: .addr name
.res MAXARGS * 2, 0