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cc65/libsrc/atari/getdefdev.s
2018-09-20 23:58:23 +02:00

128 lines
3.3 KiB
ArmAsm

;
; Freddy Offenga & Christian Groessler, December 2004
;
; function to get default device: char *_getdefdev(void);
;
; AtariDOS/MyDOS:
; Default device number is derived from DUNIT. Therefore "default
; device" is the one the program was loaded from.
;
; SpartaDOS/RealDOS:
; the ZCRNAME routine is only used to get the default drive because
; ZCRNAME has two disadvantages:
; 1. It will convert D: into D1: instead of Dn: (n = default drive)
; 2. It will give a 'no arguments' status if it detects something
; like Dn: (without filename).
;
; OS/A+ DOS:
; ZCRNAME is slightly different from SpartaDOS. It will convert D:
; into Dn: where n is the default drive.
.include "atari.inc"
.import __dos_type
.export __getdefdev ; get default device
.export __defdev ; this is the default device string (e.g. "D1:")
.ifdef DYNAMIC_DD
.constructor __getdefdev, 24
.endif
; Get default device (LBUF will be destroyed!!)
__getdefdev:
lda __dos_type ; which DOS?
cmp #XDOS
beq xdos ; XDOS detected
; cmp #OSADOS+1 ; (redundant: #OSADOS+1 = #XDOS)
bcs use_DUNIT ; neither XDOS, nor OS/A+ or SpartaDOS
ldy #BUFOFF
lda #0
sta (DOSVEC),y ; reset buffer offset
; Store dummy argument
ldy #LBUF
lda #'X'
sta (DOSVEC),y
iny
lda #ATEOL
sta (DOSVEC),y
; One extra store to avoid the buggy sequence from OS/A+ DOS:
; <D><RETURN><:> => drive number = <RETURN>
iny
sta (DOSVEC),y
; Create crunch vector
ldy #ZCRNAME+1
lda (DOSVEC),y
sta crvec+1
iny
lda (DOSVEC),y
sta crvec+2
jsr crvec
; Get default device
ldy #COMFNAM ; COMFNAM is always "Dn:"
lda (DOSVEC),y
sta __defdev
iny
lda (DOSVEC),y
done: sta __defdev+1
; Return pointer to default device
finish: lda #<__defdev
ldx #>__defdev
rts
; On AtariDOS or MyDOS, use the DUNIT variable to setup the default
; device. The default device will then be the one the program was
; loaded from.
use_DUNIT:
lda DUNIT
clc
adc #'0'
bne done ; jump always
; XDOS default device retrieval
xdos:
; check XDOS version (we need >= 2.4)
lda XGLIN
cmp #$4C ; there needs to be a 'JMP' opcode here
bne finish ; older version, use DEFAULT_DEVICE or D1:
lda XVER ; get BCD encoded version ($24 for 2.4)
cmp #$24
bcc finish ; too old, below 2.4
; good XDOS version, get default drive
lda #ATEOL
sta XLINE ; simulate empty command line
ldy #0
jsr XMOVE ; create an FMS filename (which in this case only contains the drive)
lda XFILE+1
bne done
.data
crvec: jmp $FFFF ; target address will be set to crunch vector
; Default device string
__defdev:
.ifdef DEFAULT_DEVICE
.byte 'D', '0'+DEFAULT_DEVICE, ':', 0
.else
.byte "D1:", 0
.endif