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add query_sectorsize: query sector size of disk by reading sector #4

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and making a status command ($53) to the drive: initial check-in,
needs cleanup


git-svn-id: svn://svn.cc65.org/cc65/trunk@3394 b7a2c559-68d2-44c3-8de9-860c34a00d81
This commit is contained in:
cpg 2005-02-19 01:04:41 +00:00
parent 7d824b7b7e
commit fcf1a05454
1 changed files with 114 additions and 16 deletions
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128
libsrc/atari/diopncls.s
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@ -1,20 +1,22 @@
;
; 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 sets 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.
;
; dhandle_t __fastcall__ dio_open (driveid_t drive_id);
; unsigned char __fastcall__ dio_close (dhandle_t handle);
;
.export _dio_open,_dio_close
.export _dio_open, _dio_close
.export sectsizetab
.import __oserror
.importzp ptr1,tmp1
.import __oserror, __sio_call, _dio_read
.import pushax, addysp, subysp
.importzp ptr2, tmp1, sp
.include "atari.inc"
@ -34,7 +36,7 @@ sectsizetab:
asl a ; make index from drive id
asl a
tax
lda #128 ; currently hardcoded (until I get an 815 :-)
lda #128 ; preset sectsize, will be overridden by query_sectorsize
sta sectsizetab+sst_sectsize,x
sta sectsizetab+sst_flag,x ; set flag that drive is "open"
lda #0
@ -42,8 +44,6 @@ sectsizetab:
sta __oserror ; success
tya
sta sectsizetab+sst_driveno,x
; lda #SSTIDVAL
; sta sectsizetab+sst_id+1,x
stx tmp1
lda #<sectsizetab
clc
@ -53,7 +53,8 @@ sectsizetab:
adc #0
tax
lda tmp1
rts
jmp query_sectorsize ; query drive for current sector size
; rts
_inv_drive:
lda #NONDEV ; non-existent device
@ -66,14 +67,111 @@ _inv_drive:
.proc _dio_close
sta ptr1
stx ptr1+1
sta ptr2
stx ptr2+1
lda #0
ldy #sst_flag
sta (ptr1),y
sta (ptr2),y
sta __oserror ; success
tax
rts ; return no error
.endproc
; query drive for current sector size
; procedure:
; - read sector #4 (SIO command $54) to update drive status
; read length is 128 bytes, buffer is below the stack pointer,
; sector data is ignored
; 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
; if the command returns with an error, we set sector size to 128
; bytes
;
; AX - handle
;
.proc query_sectorsize
sta ptr2
stx ptr2+1 ; remember pointer to sectsizetab entry
; jsr pushax ; handle for subsequent __sio_call
ldy #128
jsr subysp ; use buffer on the stack
lda sp
pha
lda sp+1
pha
lda ptr2
ldx ptr2+1
jsr pushax ; handle
ldx #0
lda #4
jsr pushax ; sect_num
; ldy #128
; jsr subysp ; use buffer on the stack
; lda sp
; ldx sp+1
pla
tax
pla
; jsr pushax ; buffer address (not pushed, _dio_read is __fastcall__)
jsr _dio_read ; read sector to update status
ldy #128
jsr addysp ; discard stack buffer
lda ptr2
ldx ptr2+1
jsr pushax ; handle for subsequent __sio_call
ldx #0
lda #4
jsr pushax ; dummy sector #
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
lda #0
sta (ptr2),y
iny
lda #1
; sta (ptr2),y
; bne fini2
finish: sta (ptr2),y ; set default sector size
fini2: lda ptr2
ldx ptr2+1
rts
error: ldy #sst_sectsize
s128: lda #128
bne finish
.endproc