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The way we want to use the INITBSS segment - and especially the fact that it won't have the type bss on all ROM based targets - means that the name INITBSS is misleading. After all INIT is the best name from my perspective as it serves several purposes and therefore needs a rather generic name. Unfortunately this means that the current INIT segment needs to be renamed too. Looking for a short (ideally 4 letter) name I came up with ONCE as it contains all code (and data) accessed only once during initialization.
139 lines
4.1 KiB
ArmAsm
139 lines
4.1 KiB
ArmAsm
; mainargs.s
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;
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; Ullrich von Bassewitz, 2003-03-07
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; Based on code from Stefan A. Haubenthal, <polluks@web.de>
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; 2003-05-18, Greg King
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; 2004-04-28, 2005-02-26, Ullrich von Bassewitz
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;
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; Scan a group of arguments that are in BASIC's input-buffer.
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; Build an array that points to the beginning of each argument.
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; Send, to main(), that array and the count of the arguments.
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;
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; Command-lines look like these lines:
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;
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; run
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; run : rem
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; run:rem arg1 " arg 2 is quoted " arg3 "" arg5
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;
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; "run" and "rem" are entokenned; the args. are not. Leading and trailing
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; spaces outside of quotes are ignored.
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;
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; TO-DO:
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; - The "file-name" might be a path-name; don't copy the directory-components.
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; - Add a control-character quoting mechanism.
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.constructor initmainargs, 24
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.import __argc, __argv
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.include "plus4.inc"
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MAXARGS = 10 ; Maximum number of arguments allowed
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REM = $8f ; BASIC token-code
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NAME_LEN = 16 ; Maximum length of command-name
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; Get possible command-line arguments. Goes into the special ONCE segment,
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; which may be reused after the startup code is run
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.segment "ONCE"
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initmainargs:
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; Assume that the program was loaded, a moment ago, by the traditional LOAD
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; statement. Save the "most-recent filename" as argument #0.
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lda #0 ; The terminating NUL character
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ldy FNAM_LEN
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cpy #NAME_LEN + 1
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bcc L1
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ldy #NAME_LEN ; Limit the length
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bne L1 ; Branch always
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L0: lda #FNAM ; Vector address
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jsr FETCH ; Load byte from RAM
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L1: sta name,y
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dey
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bpl L0
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inc __argc ; argc always is equal to, at least, 1
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; Find the "rem" token.
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ldx #0
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L2: lda BASIC_BUF,x
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beq done ; No "rem," no args.
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inx
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cmp #REM
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bne L2
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ldy #1 * 2
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; Find the next argument
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next: lda BASIC_BUF,x
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beq done ; End of line reached
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inx
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cmp #' ' ; Skip leading spaces
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beq next
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; Found start of next argument. We've incremented the pointer in X already, so
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; it points to the second character of the argument. This is useful since we
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; will check now for a quoted argument, in which case we will have to skip this
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; first character.
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found: cmp #'"' ; Is the argument quoted?
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beq setterm ; Jump if so
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dex ; Reset pointer to first argument character
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lda #' ' ; A space ends the argument
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setterm:sta term ; Set end of argument marker
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; Now store a pointer to the argument into the next slot. Since the BASIC
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; input buffer is located at the start of a RAM page, no calculations are
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; necessary.
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txa ; Get low byte
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sta argv,y ; argv[y]= &arg
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iny
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lda #>BASIC_BUF
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sta argv,y
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iny
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inc __argc ; Found another arg
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; Search for the end of the argument
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argloop:lda BASIC_BUF,x
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beq done
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inx
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cmp term
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bne argloop
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; We've found the end of the argument. X points one character behind it, and
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; A contains the terminating character. To make the argument a valid C string,
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; replace the terminating character by a zero.
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lda #0
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sta BASIC_BUF-1,x
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; Check if the maximum number of command line arguments is reached. If not,
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; parse the next one.
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lda __argc ; Get low byte of argument count
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cmp #MAXARGS ; Maximum number of arguments reached?
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bcc next ; Parse next one if not
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; (The last vector in argv[] already is NULL.)
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done: lda #<argv
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ldx #>argv
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sta __argv
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stx __argv + 1
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rts
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.segment "INIT"
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term: .res 1
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name: .res NAME_LEN + 1
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.data
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; char* argv[MAXARGS+1]={name};
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argv: .addr name
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.res MAXARGS * 2
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