;;	;;	;;  1541 CFS implementation	;;	;; Architecture:	;; 	;; Functionality split between C64 and 1541: 1541 performs	;; directory lookup and finding files. 1541 communicates track/sector	;; address of file, C64 requests data to be read from track/sector.	;;	;;  Example: reading directory	;;	;;  C64:	DIR	;;  1541:	directory entries in CFS format	;;	;;  Example: opening file	;;	;;  C64:	FILE filename	;;  1541:	track/sector	;;	;;  Example: reading file	;;	;;  C64:	track/sector, length	;;  1541:	length, data, track/sector			.export _c64_dio_asm_init	.export _c64_dio_asm_read_block	.export _c64_dio_asm_write_block		.export _c64_dio_asm_track, _c64_dio_asm_sector	.export _c64_dio_asm_ptr		.importzp ptr1, ptr2			;; job code $80 read, $90 write	ciout    = $ffa8listen   = $ffb1second   = $ff93unlsn    = $ffaenbytes   = 34esc      = $42blockread = 1blockwrite = 2errok    = 0errerr   = 1.data_c64_dio_asm_track: .byte 0_c64_dio_asm_sector: .byte 0_c64_dio_asm_ptr: .byte 0,0			.code;---------------------------------------_cfs_1541_read:	;; First send READ command to drive		lda #READ_CMD	jsr send	;; If drive do not respond we must download drive code	cmp #ERR_NOT_RESPONDING	bne notload		jsr download	lda #read	jsr sendnotload:	;; Send file descriptor and number of bytes to read	lda _cfs_1541_fd	jsr send	lda _cfs_1541_bytes	jsr send	lda _cfs_1541_ptr	sta ptr1	lda _cfs_1541_ptr + 1	sta ptr1 + 1	;; Read bytes from drive	ldy #0:		jsr recv	sta (ptr1),y	iny		cpy _cfs_1541_bytes	bne -	;; Read the number of bytes that were actually read from the file	jsr recv	;; Return the number of bytes read		rts;---------------------------------------	_c64_dio_asm_read_block:		  	lda #BLOCKREAD_CMD         jsr send         lda _c64_dio_asm_track         jsr send	 lda _c64_dio_asm_sector         jsr send         jsr recv         cmp #errok         bne readerr	 lda _c64_dio_asm_ptr	 sta ptr1 	 lda _c64_dio_asm_ptr+1	 sta ptr1+1        ldy #0readl:	         jsr recv         sta (ptr1),y         iny         bne readl         clc	 lda #0         tax	         rtsreaderr:		;          sta $07c0		 jsr recv	; 	 sta $07c1         ldx #0         rts;---------------------------------------_c64_dio_asm_write_block:		 	lda #blockwrite         jsr send         lda _c64_dio_asm_track         jsr send         lda _c64_dio_asm_sector         jsr send	 lda _c64_dio_asm_ptr	 sta ptr1 	 lda _c64_dio_asm_ptr+1	 sta ptr1+1        ldy #0writel:         lda (ptr1),y	         jsr send         iny         bne writel         jsr recv         cmp #errok         bne writeerr         lda #0	 tax         rtswriteerr:		;          sta $07c0	 jsr recv	; 	 sta $07c1         ldx #0         rts;---------------------------------------_c64_dio_asm_init:		         sta devnr         lda #$00         sta drvmem         lda #$05         sta drvmem+1         lda #<drive         sta ptr1         lda #>drive         sta ptr1+1       ; lda devnr       ; ldx #<icmd       ; ldy #>icmd       ; jsr drvcmd       ; jsr unlsnmwl:	         lda devnr         ldx #<mwcmd         ldy #>mwcmd         jsr drvcmd         ldy #0         lda (ptr1),y         jsr ciout         iny         cpy #nbytes         bne *-8         jsr unlsn         lda drvmem         clc         adc #nbytes         sta drvmem         lda drvmem+1         adc #0         sta drvmem+1         lda ptr1         clc         adc #nbytes         sta ptr1         tax         lda ptr1+1         adc #0         sta ptr1+1         cpx #<driveend         sbc #>driveend         bcc mwl         lda devnr         ldx #<mecmd         ldy #>mecmd         jsr drvcmd         jsr unlsn         rts;---------------------------------------drvcmd:	         stx ptr2         sty ptr2+1         jsr listen         lda #$6f         jsr second         ldy #0         lda (ptr2),y         sta drvcmdcmp+1         inc ptr2         bne *+4         inc ptr2+1         ldy #0         lda (ptr2),y         jsr ciout         inydrvcmdcmp:	 cpy #0         bne *-8         rts;---------------------------------------devnr:	    .byte 8mwcmd:	    .byte 6	.byte $4d, $2d, $57drvmem:	   .word $0500         .byte nbytes         .byte 0mecmd:	    .byte 2	 .byte $55, $33         .byte 0;---------------------------------------send:         sta ptr2         ldx #7sendl:	         lsr ptr2         lda $dd00         and #$df         ora #$10         bcc *+4         eor #$30         sta $dd00         lda #$c0         bit $dd00         bne *-3         lda $dd00         and #$cf         sta $dd00         lda $dd00         and #$c0         eor #$c0         bne *-7         dex         bpl sendl	 ldx $d020	 lda #1	 sta $d020	 stx $d020		         rts;---------------------------------------recv:	 ldx $d020	 lda #0	 sta $d020	 stx $d020	         ldx #7recvl:	         lda $dd00         and #$c0         eor #$c0         beq *-7         asl a         lda $dd00         and #$df         ora #$10         bcs *+4         eor #$30         sta $dd00         ror ptr2         lda #$c0         bit $dd00         beq *-3         lda $dd00         and #$cf         sta $dd00         dex         bpl recvl         lda ptr2         rts;---------------------------------------;---------------------------------------;the code residing in the drive:;---------------------------------------dtmp     = $46dtmp2    = $97dbuf     = $0300dbufcmd  = $00dbuftrack = $06dbufsect = $07retries  = 10bretries = 2;---------------------------------------drive  :			.org $0500         cld         tsx         stx dstack         sei         jsr ledoffdrivel:	         jsr dload         jsr ledoff         cli         jmp drivel;---------------------------------------ledon:	         lda $1c00         ora #$08         sta $1c00         rtsledoff:	         lda $1c00         and #$f7         sta $1c00         rts;---------------------------------------drecv:	         ldx #7drecvl:	         lda $1800         bmi atn         and #5         beq *-7         lsr a         lda #2         bcc *+4         lda #8         sta $1800         ror dtmp         lda $1800         bmi atn         and #5         eor #5         beq *-9         lda #0         sta $1800         dex         bpl drecvl         lda dtmp         rts;---------------------------------------atn:	         ldx dstack         txs         cli         rts;---------------------------------------dsend:	         sta dtmp         ldx #7dsendl:	         lsr dtmp         lda #2         bcs *+4         lda #8         sta $1800         lda $1800         bmi atn         and #5         eor #5         bne *-9         sta $1800         lda #5         bit $1800         bne *-3         dex         bpl dsendl         rts;---------------------------------------dload:         ldy #0         jsr drecv         sta dcmd	         jsr ledon	         jsr drecv         sta dbuftrack         jsr drecv         sta dbufsect	 lda dcmd	 cmp #blockwrite	 bne dblockreaddblockwrite:         ldy #0drecvpl:	         jsr drecv         sta dbuf,y	         iny         bne drecvpl		 jmp dputsectdblockread:		         jsr dgetsectdsendpage:	         ldy #0dsendpl:	         lda dbuf,y         jsr dsend         iny         bne dsendpl         rts;---------------------------------------dgetsect:	       ; stx dbuftrack       ; sty dbufsect         ldx #retriesdgetsectl:	         lda #$80         sta dbufcmd         cli:         lda dbufcmd         bmi :-         sei         cmp #1         beq dgsnoerr         cpx #0         beq dgsserr         dex         cpx #bretries         bcs dgetsectl         pha         lda #$c0         sta dbufcmd         cli:		         lda dbufcmd         bmi :-         pla         cpx #0         bne dgetsectldgsserr:	         pha         lda #errerr         jsr dsend         pla         jsr dsend         rtsdgsnoerr:	         lda #errok         jsr dsend         rts;---------------------------------------dputsect:	       ; stx dbuftrack       ; sty dbufsect         ldx #retriesdputsectl:	         lda #$90         sta dbufcmd         cli:         lda dbufcmd         bmi :-         sei         cmp #1         beq dpsnoerr         cpx #0         beq dpsserr         dex         cpx #bretries         bcs dputsectl         pha         lda #$c0         sta dbufcmd         cli:		         lda dbufcmd         bmi :-         pla         cpx #0         bne dputsectldpsserr:	         pha         lda #errerr         jsr dsend         pla         jsr dsend         rtsdpsnoerr:	         lda #errok         jsr dsend         rts;---------------------------------------led:	      .byte 0,0dstack:	   .byte 0dcmd:	     .byte 0.RELOCdriveend: