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6198e10f67
Stefan Dorndorf, author of XDOS, pointed out that retrieving the default device by looking at an undocumented memory location won't work in future XDOS versions. He also showed a way to get the default device in a compatible manner. This change implements his method and adds a version check (XDOS versions below 2.4 don't support this -- for them the behaviour will be the same as, for example, AtariDOS: no notion of a default drive).
114 lines
2.9 KiB
ArmAsm
114 lines
2.9 KiB
ArmAsm
;
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; Freddy Offenga & Christian Groessler, December 2004
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;
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; function to get default device: char *_getdefdev(void);
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;
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; SpartaDOS:
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; the ZCRNAME routine is only used to get the default drive because
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; ZCRNAME has two disadvantages:
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; 1. It will convert D: into D1: instead of Dn: (n = default drive)
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; 2. It will give a 'no arguments' status if it detects something
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; like Dn: (without filename).
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;
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; OS/A+ DOS:
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; ZCRNAME is slightly different from SpartaDOS. It will convert D:
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; into Dn: where n is the default drive.
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.include "atari.inc"
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.import __dos_type
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.export __getdefdev ; get default device
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.export __defdev ; this is the default device string (e.g. "D1:")
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.ifdef DYNAMIC_DD
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.constructor __getdefdev, 24
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.endif
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; Get default device (LBUF will be destroyed!!)
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__getdefdev:
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lda __dos_type ; which DOS?
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cmp #XDOS
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beq xdos ; only supported on XDOS ...
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; cmp #OSADOS+1 ; (redundant: #OSADOS+1 = #XDOS)
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bcs finish ; ... and on OS/A+ and SpartaDOS
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ldy #BUFOFF
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lda #0
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sta (DOSVEC),y ; reset buffer offset
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; Store dummy argument
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ldy #LBUF
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lda #'X'
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sta (DOSVEC),y
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iny
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lda #ATEOL
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sta (DOSVEC),y
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; One extra store to avoid the buggy sequence from OS/A+ DOS:
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; <D><RETURN><:> => drive number = <RETURN>
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iny
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sta (DOSVEC),y
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; Create crunch vector
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ldy #ZCRNAME+1
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lda (DOSVEC),y
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sta crvec+1
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iny
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lda (DOSVEC),y
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sta crvec+2
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jsr crvec
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; Get default device
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ldy #COMFNAM ; COMFNAM is always "Dn:"
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lda (DOSVEC),y
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sta __defdev
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iny
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lda (DOSVEC),y
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done: sta __defdev+1
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; Return pointer to default device
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finish: lda #<__defdev
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ldx #>__defdev
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rts
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; XDOS default device retrieval
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xdos:
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; check XDOS version (we need >= 2.4)
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lda XGLIN
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cmp #$4C ; there needs to be a 'JMP' opcode here
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bne finish ; older version, use DEFAULT_DEVICE or D1:
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lda XVER ; get BCD encoded version ($24 for 2.4)
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cmp #$24
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bcc finish ; too old, below 2.4
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; good XDOS version, get default drive
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lda #ATEOL
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sta XLINE ; simulate empty command line
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ldy #0
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jsr XMOVE ; create an FMS filename (which in this case only contains the drive)
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lda XFILE+1
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bne done
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.data
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crvec: jmp $FFFF ; target address will be set to crunch vector
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; Default device string
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__defdev:
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.ifdef DEFAULT_DEVICE
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.byte 'D', '0'+DEFAULT_DEVICE, ':', 0
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.else
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.byte "D1:", 0
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.endif
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