asm: add dos33 routines taken from my ll program
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Vince Weaver
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; File I/O routines based on sample code in
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; "Beneath Apple DOS" by Don Worth and Pieter Lechner
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;; For the disk-read code
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RWTSH EQU $F1
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RWTSL EQU $F0
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DOSBUFH EQU $EF
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DOSBUFL EQU $EE
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FILEMH EQU $ED
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FILEML EQU $EC
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;; DOS Constants
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OPEN EQU $01
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CLOSE EQU $02
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READ EQU $03
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WRITE EQU $04
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DELETE EQU $05
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CATALOG EQU $06
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LOCK EQU $07
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UNLOCK EQU $08
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RENAME EQU $09
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POSITION EQU $0A
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INIT EQU $0B
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VERIFY EQU $0C
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LOCATE_FILEM_PARAM EQU $3DC
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LOCATE_RWTS_PARAM EQU $3E3
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FILEMANAGER EQU $3D6
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;================================
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; read from disk
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;================================
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jsr LOCATE_FILEM_PARAM ; load file manager param list
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; Y=low A=high
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sta FILEMH
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sty FILEML
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ldy #7 ; file type offset = 7
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lda #0 ; 0 = text
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sta (FILEML),y
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iny ; filename ptr offset = 8
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lda #<filename
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sta (FILEML),y
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iny
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lda #>filename
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sta (FILEML),y
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ldx #1 ; open existing file
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jsr open ; open file
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jsr read ; read buffer
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jsr close ; close file
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;=================================
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; get_dos_buffer
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;=================================
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;
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; Dos buffer format
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; 0x000-0x0ff = data buffer
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; 0x100-0x1ff = t/s list buffer
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; 0x200-0x22c = file manager workarea (45 bytes)
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; 0x22d-0x24a = file name buffer
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; 0x24b-0x24c = address of file manager workarea
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; 0x24d-0x24e = address of t/s list buffer
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; 0x24f-0x250 = adress of data sector buffer
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; 0x251-0x252 = address of file name field for the next buffer
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; In DOS, $3D2 points to 0x22d of first buffer
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; add 0x24 to get chain pointer
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open:
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; allocate one of the DOS buffers so we don't have to set them up
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allocate_dos_buffer:
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lda $3D2 ; DOS load point
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sta DOSBUFH
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ldy #0
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sty DOSBUFL
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buf_loop:
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lda (DOSBUFL),Y ; locate next buffer
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pha ; push on stack
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; we need this later
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; to test validity
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iny ; increment y
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lda (DOSBUFL),Y ; load next byte
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sta DOSBUFH ; store to buffer pointerl
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pla ; restore value from stack
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sta DOSBUFL ; store to buffer pointerh
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bne found_buffer ; if not zero, found a buffer
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lda DOSBUFH ; also if not zero, found a buffer
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beq error ; no buffer found, exit
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found_buffer:
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ldy #0 ; get filename
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lda (DOSBUFL),Y ; get first byte
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beq good_buffer ; if zero, good buffer
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; in use
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ldy #$24 ; point to next
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bne buf_loop ; and loop
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good_buffer:
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lda #$78
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sta (DOSBUFL),Y ; mark as in use (can be any !0)
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keep_opening:
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ldy #0
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lda #OPEN ; set operation code to OPEN
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sta (FILEML),y
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ldy #2 ; point to record length
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lda #0 ; set it to zero (16-bits)
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sta (FILEML),y
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iny
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sta (FILEML),y
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iny ; point to volume num (0=any)
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sta (FILEML),y
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jsr LOCATE_RWTS_PARAM ; get current RWTS parameters
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; so we can get disk/slot info
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sty RWTSL
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sta RWTSH
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ldy #1
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lda (RWTSL),y ; get slot*16
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lsr a
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lsr a
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lsr a
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lsr a ; divide by 16
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ldy #6 ; address of slot
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sta (FILEML),y ; store it
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ldy #2
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lda (RWTSL),y ; get drive
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ldy #5 ; address of drive
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sta (FILEML),y
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filemanager_interface:
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ldy #$1E
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dbuf_loop:
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lda (DOSBUFL),y ; get three buffer pointers
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pha ; push onto stack
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iny ; increment pointer
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cpy #$24 ; have we incremented 6 times?
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bcc dbuf_loop ; if not, loop
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ldy #$11 ; point to the end of the same struct
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; in file manager
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fmgr_loop:
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pla ; pop value
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sta (FILEML),Y ; store it
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dey ; work backwards
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cpy #$c ; see if we are done
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bcs fmgr_loop ; loop
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jmp FILEMANAGER ; run filemanager
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;====================
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; close DOS file
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;====================
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close:
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ldy #0 ; command offset
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lda #CLOSE ; load close
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sta (FILEML),y
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jsr filemanager_interface
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ldy #0 ; mark dos buffer as free again
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tya
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sta (DOSBUFL),y
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rts
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;=========================
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; read from dos file
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;=========================
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read:
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ldy #0 ; command offset
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lda #READ
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sta (FILEML),y
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iny ; point to sub-opcode
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lda #2 ; "range of bytes"
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sta (FILEML),y
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ldy #6 ; point to number of bytes to read
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lda #$ff
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sta (FILEML),y ; we want to read 255 bytes
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iny
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lda #$00
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sta (FILEML),y
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ldy #8 ; buffer address
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lda #<disk_buff
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sta (FILEML),y
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iny
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lda #>disk_buff
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sta (FILEML),y
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bne filemanager_interface ; same as JMP
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filename:
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; CPUINFO__6502 (padded to be 30 chars long)
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.byte $C3,$D0,$D5,$C9,$CE,$C6,$CF,$DF
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.byte $DF,$B6,$B5,$B0,$B2,$A0,$A0,$A0
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.byte $A0,$A0,$A0,$A0,$A0,$A0,$A0,$A0
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.byte $A0,$A0,$A0,$A0,$A0,$A0
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@ -0,0 +1,7 @@
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+ Load from disk
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+ Starfield
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+ Volume Bars
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+ Print Descriptive Text
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+ Print time
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+ LZ4 decompression
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+ Loop support
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