; read any file slot 6 version ; based on FASTLD6 and RTS copyright (c) Peter Ferrie 2011-2013,2018 ; modified to assembled with ca65 -- vmw ; added code to patch it to run from current disk slot -- vmw ; USAGE: ; file to load in namlo:namhi ; Loads file contents to addr from filesystem ; also stores filesize in ldsizel:ldsizeh dirbuf = $6000 ; note, don't put this immediately below ; the value being read as destaddr-4 ; is temporarily overwritten during read ; process ;====================== ; filename to open is 30-character Apple text: filename: .byte $A0,$A0,$A0,$A0,$A0,$A0,$A0,$A0 .byte $A0,$A0,$A0,$A0,$A0,$A0,$A0,$A0 .byte $A0,$A0,$A0,$A0,$A0,$A0,$A0,$A0 .byte $A0,$A0,$A0,$A0,$A0,$A0 ;======================================================= ;======================================================= ;======================================================= ;unhook DOS and build nibble table rts_init: ; patch to use current drive ; locate input paramater list jsr $3E3 ; result is in A:Y sta $FF sty $FE ldy #1 lda ($FE),y ; list+1 should have slot<<8 ora #$80 ; add in $80 ; c0e0 sta mlsmc06+1 ; c0e8 clc adc #8 sta mlsmc02+1 ; c0e9 clc adc #1 sta mlsmc01+1 ; c0ec clc adc #3 sta mlsmc03+1 sta mlsmc04+1 sta mlsmc05+1 jsr $fe93 ; clear COUT jsr $fe89 ; clear KEYIN ;======================== ; Create nibble table ; Note: the table starts 16 bytes in, and is sparse ; so it doesn't entirely look like the DOS33 table at ldy #0 ldx #3 L1: stx $3c ; store tempx (3?) txa ; a=x (a=3) asl ; a*=2 (a=6) bit $3c ; a&tempx, set N/V (a=6) beq L3 ; if 0, skip to L3 ora $3c ; a|=tempx (a=7) eor #$ff ; a=~a (a=f8) and #$7e ; a&=0x7e 0111 1110 (a=78) L2: bcs L3 ; this set way back at asl?? lsr ; a>>1 a=3c c=0 ; a=1e c=0 ; a=0f c=0 ; a=07 c=1 bne L2 ; if a!=0 goto l2 tya ; if a==0, a=y sta nibtbl, x ; write out to table iny ; increment y L3: inx ; increment x x=4, a=0f bpl L1 ; loop while high bit not set rts ;======================================================= ;======================================================= ;======================================================= ; filename in OUTL:OUTH opendir_filename: ; clear out the filename with $A0 (space) lda #filename sta namhi ldy #29 wipe_filename_loop: lda #$A0 sta (namlo),Y dey bpl wipe_filename_loop ldy #0 copy_filename_loop: lda (OUTL),Y beq copy_filename_done sta (namlo),Y iny bne copy_filename_loop copy_filename_done: ; fallthrough ;======================================================= ;======================================================= ;======================================================= ;=========================== ; opendir ;=========================== ; turn on drive and read volume table of contents opendir: mlsmc01:lda $c0e9 ; turn slot#6 drive on ldx #0 stx adrlo ; zero out adrlo stx secsize ; zero out secsize lda #$11 ; a=$11 (VTOC) jsr readdirsec firstent: lda dirbuf+1 ; lock if entry not found entry_not_found: beq entry_not_found ; read directory sector ldx dirbuf+2 jsr seekread1 ldy #7 ;number of directory entries in a sector ldx #$2b ;offset of filename in directory entry nextent: tya pha ; was **phy** txa pha ; was **phx** ldy #$1d ; match name backwards (slower but smaller) L4: lda (namlo), y cmp dirbuf, x beq foundname pla ; move to next directory in this block, if possible clc adc #$23 tax pla tay ; was **ply** dey bne nextent beq firstent ; was **bra** foundname: dex dey bpl L4 pla tay ; was **ply** pla ; read track/sector list lda dirbuf-32, y ldx dirbuf-31, y jsr seekread1 ; read load offset and length info only, initially lda #filbuf jsr seekread ; reduce load offset by 4, to account for offset and length sec lda filbuf sbc #4 sta adrlo lda filbuf+1 sbc #0 sta adrhi ; save on stack bytes that will be overwritten by extra read ldy #3 L5: lda (adrlo), y pha dey bpl L5 lda adrhi pha lda adrlo pha ; increase load size by 4, to account for offst and length lda filbuf+2 sta ldsizel ; store out raw size adc #3 sta sizelo sta secsize lda filbuf+3 sta ldsizeh ; store out raw size adc #0 sta sizehi sta ldsizeh beq readfirst lda #0 ; was **stz secsize** sta secsize readfirst: ldy #$0c ; read a file sector readnext: tya pha lda dirbuf, y ; A = track ldx dirbuf+1, y ; x = sector jsr seekread1 pla tay ; if low count is non-zero then we are done ; (can happen only for partial last block) lda secsize bne readdone ; continue if more than $100 bytes left dec sizehi bne L6 ; set read size to min(length, $100) lda sizelo beq readdone sta secsize L6: inc adrhi iny iny bne readnext ; save current address for after t/s read lda adrhi pha lda adrlo pha lda #0 sta adrlo ; was **stz adrlo** ; read next track/sector sector lda dirbuf+1 ldx dirbuf+2 jsr readdirsec clc ; restore current address readdone: pla ; sta adrhi ; pla sta adrlo ; code originally had this backwards pla sta adrhi bcc readfirst mlsmc02:lda $c0e8 ; restore from stack bytes that were overwritten by extra read ldx #3 ldy #0 L7: pla sta (adrlo), y iny dex bpl L7 rts ;====================== ; readdirsec ;====================== ; a = track? ; x = sector? readdirsec: ldy #>dirbuf seekread: sty adrhi seekread1: sta phase lda sectbl, x sta reqsec jsr readadr ; if track does not match, then seek cpx phase beq checksec jsr seek ;========================================= ; re merge in with qkumba's recent changes ; to fix seek problem? ;========================================= ; [re-]read sector re_read_addr: jsr readadr checksec: cmp reqsec bne re_read_addr ;========================= ; read sector data ;========================= readdata: jsr readd5aa eor #$ad ; zero A if match bne re_read_addr L12: mlsmc03:ldx $c0ec ; read until valid data (high bit set) bpl L12 eor nibtbl-$80, x sta bit2tbl-$aa, y iny bne L12 L13: mlsmc04:ldx $c0ec ; read until valid data (high bit set) bpl L13 eor nibtbl-$80, x sta (adrlo), y ; the real address iny cpy secsize bne L13 ldy #0 L14: ldx #$a9 L15: inx beq L14 lda (adrlo), y lsr bit2tbl-$aa, x rol lsr bit2tbl-$aa, x rol sta (adrlo), y iny cpy secsize bne L15 rts ; no tricks here, just the regular stuff ;======================= ; readaddr -- read the address field ;======================= ; Find address field, put track in cutrk, sector in tmpsec readadr: jsr readd5aa cmp #$96 bne readadr ldy #3 ; three? ; first read volume/volume ; then track/track ; then sector/sector? adr_read_two_bytes: tax jsr readnib rol sta tmpsec jsr readnib and tmpsec dey bne adr_read_two_bytes rts ;======================== ; make sure we see the $D5 $AA pattern readd5aa: L16: jsr readnib L17: cmp #$d5 bne L16 jsr readnib cmp #$aa bne L17 tay ; we need Y=#$AA later readnib: mlsmc05:lda $c0ec ; read until valid (high bit set) bpl readnib seekret: rts ;===================== ; SEEK ;===================== ; current track in X? ; desired track in phase seek: ldy #0 sty step asl phase ; multiply by two txa ; current track? asl ; mul by two copy_cur: tax sta tmptrk sec sbc phase beq L22 bcs L18 eor #$ff inx bcc L19 L18: sbc #1 dex L19: cmp step bcc L20 lda step L20: cmp #8 bcs L21 tay sec L21: txa pha ldx step1, y L22: php bne L24 L23: clc lda tmptrk ldx step2, y L24: stx tmpsec and #3 rol tax lsr mlsmc06:lda $c0e0, x L25: ldx #$12 L26: dex bpl L26 dec tmpsec bne L25 bcs L23 plp beq seekret pla inc step bne copy_cur step1: .byte $01, $30, $28, $24, $20, $1e, $1d, $1c step2: .byte $70, $2c, $26, $22, $1f, $1e, $1d, $1c sectbl: .byte $00,$0d,$0b,$09,$07,$05,$03,$01,$0e,$0c,$0a,$08,$06,$04,$02,$0f ; From $BA96 of DOS33 nibtbl: .res 128 ; = * ; .byte $00,$01,$98,$99,$02,$03,$9C,$04 ; $BA96 ; 00 ; .byte $05,$06,$A0,$A1,$A2,$A4,$A4,$A5 ; $BA9E ; 08 ; .byte $07,$08,$A8,$A9,$AA,$09,$0A,$0B ; $BAA6 ; 10 ; .byte $0C,$0D,$B0,$B1,$0E,$0F,$10,$11 ; $BAAE ; 18 ; .byte $12,$13,$B8,$14,$15,$16,$17,$18 ; $BAB6 ; 20 ; .byte $19,$1A,$C0,$C1,$C2,$C3,$C4,$C5 ; $BABE ; 28 ; .byte $C6,$C7,$C8,$C9,$CA,$1B,$CC,$1C ; $BAC6 ; 30 ; .byte $1D,$1E,$D0,$D1,$D2,$1E,$D4,$D5 ; $BACE ; 38 ; .byte $20,$21,$D8,$22,$23,$24,$25,$26 ; $BAD6 ; 40 ; .byte $27,$28,$E0,$E1,$E2,$E3,$E4,$29 ; $BADE ; 48 ; .byte $2A,$2B,$E8,$2C,$2D,$2E,$2F,$30 ; $BAE6 ; 50 ; .byte $31,$32,$F0,$F1,$33,$34,$35,$36 ; $BAEE ; 58 ; .byte $37,$38,$F8,$39,$3A,$3B,$3C,$3D ; $BAF6 ; 60 ; .byte $3E,$3F,$13,$00,$01,$02,$01,$00 ; $BAFE ; 68 ; .byte $00,$00,$00,$00,$00,$00,$00,$00 ; .byte $00,$00,$00,$00,$00,$00,$00,$00 bit2tbl: .res 86 ; = nibtbl+128 filbuf: .res 4 ; = bit2tbl+86 ;dataend = filbuf+4