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;
; Oliver Schmidt, 31.03.2005
;
; unsigned __fastcall__ dio_query_sectcount (dhandle_t handle);
;
.export _dio_query_sectcount
.import _dio_query_sectsize, _malloc, _free
.include "zeropage.inc"
.include "errno.inc"
.include "mli.inc"
_dio_query_sectcount:
; Set handle
sta mliparam + MLI::ON_LINE::UNIT_NUM
; Get ProDOS 8 block size (clears __oserror)
jsr _dio_query_sectsize
; Alloc buffer
jsr _malloc
sta ptr4
stx ptr4+1
; Set buffer
sta mliparam + MLI::ON_LINE::DATA_BUFFER
stx mliparam + MLI::ON_LINE::DATA_BUFFER+1
; Check buffer (hibyte is enough)
txa
beq nomem
; Get device state
lda #ON_LINE_CALL
ldx #ON_LINE_COUNT
jsr callmli
bcs check
; UNIT_NUM already set
.assert MLI::RW_BLOCK::UNIT_NUM = MLI::ON_LINE::UNIT_NUM, error
; DATA_BUFFER already set
.assert MLI::RW_BLOCK::DATA_BUFFER = MLI::ON_LINE::DATA_BUFFER, error
; Read volume directory key block
tax ; A = 0
lda #$02
sta mliparam + MLI::RW_BLOCK::BLOCK_NUM
stx mliparam + MLI::RW_BLOCK::BLOCK_NUM+1
lda #READ_BLOCK_CALL
ldx #RW_BLOCK_COUNT
jsr callmli
bcs oserr
; Get and save total blocks from volume directory header
ldy #$29
lda (ptr4),y
pha
iny
lda (ptr4),y
pha
; Cleanup buffer
done: lda ptr4
ldx ptr4+1
jsr _free
; Restore total blocks and return
pla
tax
pla
rts
nomem: lda #$FF ; Error code for sure not used by MLI
oserr: sta __oserror
; Save total blocks for failure
lda #$00
pha
pha
beq done ; Branch always
; Check for non-ProDOS disk
check: cmp #$52 ; "Not a ProDOS volume"
bne oserr
sta __oserror
; Save total blocks for a 16-sector disk
lda #<280
pha
lda #>280
pha
bne done ; Branch always
|
