;
-; Christian Groessler, October 2000
+; Christian Groessler, February 2005
;
-; This file provides the __dio_open and __dio_close functions
+; This file provides the _dio_open and _dio_close functions
; Since on the Atari no real open and close is necessary, they
-; do not much. The __dio_open queries the sector size of the
-; drive which is later used by the _dio_read and _dio_write
-; functions.
+; do not open or close something. The _dio_open sets the sector
+; size of the drive which is later used by the _dio_read and
+; _dio_write functions. To query the sector size, the _dio_open
+; accesses the disk drive.
;
-; unsigned char __fastcall__ _dio_open (_driveid_t drive_id);
-; unsigned char __fastcall__ _dio_close (_driveid_t drive_id);
+; dhandle_t __fastcall__ dio_open (unsigned char device);
+; unsigned char __fastcall__ dio_close (dhandle_t handle);
;
- .export __dio_open,__dio_close
+ .export _dio_open, _dio_close
.export sectsizetab
+ .import __oserror, __sio_call, _dio_read
+ .import pushax, addysp, subysp
+ .importzp ptr2, sp
.include "atari.inc"
+
.bss
sectsizetab:
- .res NUMDRVS * 2
+ .res NUMDRVS * sst_size
.code
+; code for _dio_open
+
+_inv_drive:
+ lda #NONDEV ; non-existent device
+ sta __oserror
+ lda #0
+ tax
+ rts ; return NULL
-.proc __dio_open
+_dio_open:
- asl a ; make index from drive id
+ cmp #NUMDRVS ; valid drive id?
+ bcs _inv_drive
+ tay ; drive #
+ asl a ; make index from drive id
+ asl a
tax
- lda #128 ; currently hardcoded (until I get an 815 :-)
- sta sectsizetab,x
+ lda #128 ; preset sectsize
+ sta sectsizetab+sst_sectsize,x
+ sta sectsizetab+sst_flag,x ; set flag that drive is "open"
lda #0
- sta sectsizetab+1,x
+ sta sectsizetab+sst_sectsize+1,x
+ sta __oserror ; success
+ tya
+ sta sectsizetab+sst_driveno,x
+ stx ptr2
+ lda #<sectsizetab
+ clc
+ adc ptr2
+ sta ptr2
+ lda #>sectsizetab
+ adc #0
+ tax
+ stx ptr2+1 ; ptr2: pointer to sectsizetab entry
+
+; query drive for current sector size
+; procedure:
+; - read sector #4 (SIO command $54) to update drive status;
+; read length is 128 bytes, buffer is allocated on the stack,
+; sector data is ignored;
+; returned command status is ignored, we will get an error with
+; a DD disk anyway (read size 128 vs. sector size 256);
+; - issue SIO command $53 (get status) to retrieve the sector size;
+; use the DVSTAT system area as return buffer;
+; if the command returns with an error, set sector size to 128
+; bytes;
+;
- ; fall thru to __dio_close
+ ldy #128
+ jsr subysp ; allocate buffer on the stack
-.endproc
+ lda sp
+ pha
+ lda sp+1
+ pha ; save sp (buffer address) on processor stack
+
+ lda ptr2
+ ldx ptr2+1
+ jsr pushax ; handle
+
+ ldx #0
+ lda #4
+ jsr pushax ; sect_num
+
+ pla
+ tax
+ pla ; AX - buffer address
+
+ ; sst_sectsize currently 128
+ jsr _dio_read ; read sector to update status
+
+ ldy #128
+ jsr addysp ; discard stack buffer
+
+ lda ptr2
+ ldx ptr2+1
+ jsr pushax ; handle
-.proc __dio_close
+ ldx #0
+ lda #4
+ jsr pushax ; dummy sector #, ignored by this SIO command,
+ ; but set to circumvent the special 1-3 sector
+ ; handling in __sio_call
+ ldx #>DVSTAT
+ lda #<DVSTAT
+ jsr pushax ; buffer address
+
+ ldy #sst_sectsize
+ lda #4
+ sta (ptr2),y ; 4 bytes transfer
+
+ ldx #%01000000 ; direction value
+ lda #SIO_STAT ; get status
+
+ jsr __sio_call
+
+ bmi error
+
+ ldy #sst_sectsize
+ lda DVSTAT
+ and #%100000
+ beq s128
+
+;s256
+ lda #0
+ sta (ptr2),y
+ iny
+ lda #1
+
+finish: sta (ptr2),y ; set default sector size
+fini2: lda ptr2
+ ldx ptr2+1
+ rts
+
+error: ldy #sst_sectsize
+s128: lda #128
+ bne finish
+
+; end of _dio_open
+
+
+.proc _dio_close
+
+ sta ptr2
+ stx ptr2+1
lda #0
+ ldy #sst_flag
+ sta (ptr2),y
+ sta __oserror ; success
tax
- rts ; return no error
+ rts ; return no error
.endproc
-
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