;
; this file provides the _dio_read function
;
-; unsigned char __fastcall__ _dio_read(_driveid_t drive_id, _sectnum_t sect_num, void *buffer);
-; _driveid_t - 8bit
-; _sectnum_t - 16bit
+; unsigned char __fastcall__ dio_read(dhandle_t handle,unsigned sect_num,void *buffer);
+; dhandle_t - 16bit (ptr)
;
-
- .export __dio_read
- .import popa,popax
+ .import __sio_call,pushax
+ .export _dio_read
.include "atari.inc"
-.proc __dio_read
-
- sta DBUFLO ; set buffer address into DCB
- stx DBUFHI
- jsr popax
- sta DAUX1 ; set sector #
- stx DAUX2
- jsr popa
- cmp #16
- bcs _inv_dev ; invalid device #
- adc #1
- sta DUNIT ; unit number (d1,d2,d3,...)
- lda #$31 ; D1 (drive_id == 0) has id $31
- sta DDEVIC
- lda #0
- sta DBYTHI ; high byte of bytes to transfer
- lda #%01000000 ; indicate i/o direction (read)
- sta DSTATS
- lda #15
- sta DTIMLO ; value got from DOS source
- lda #128
- sta DBYTLO ; low byte of bytes to transfer
- lda #SIO_READ ; read sector
- sta DCOMND
-
- jsr SIOV ; execute
+.proc _dio_read
- ldx #0
- lda DSTATS
- bmi _req_err ; error occurred
- txa ; no error occurred
-_req_err:
- rts
-
-_inv_dev:
- ldx #0
- lda #NONDEV ; non-existent device error
- rts
+ jsr pushax ; push buffer address
+ ldx #%01000000 ; direction value
+ lda #SIO_READ ; read sector command
+ jmp __sio_call ; do the call and return to the user
.endproc
+