******************************************************************* * * * Hardware-File-Loader-Routine coded by Henning Saul for AFL * * * * and published in Cracker Journal #25 by ALPHA FLIGHT * ******************************************************************* * Notes: * * 1. The Load-Routine doesn't calc any checksum * * 2. The Filename in line 336 MUST look like the real * * filename on the disk (take care of big&small chars!!) * * 3. In this version the loader only works with drive 0, * * so filenames like 'df1:Anything' won't work * 4. If there are some lame-coded parts in this source, * * please don't care as I do.... * ******************************************************************* * for any LEGAL reason * * just call: 04124/2633 (ask for Henning/after 6 pm) * * or write to: Henning Saul * * Bgm.-Schinkel-Str. 8 * * W-2208 Glückstadt * * Germany * * * ******************************************************************* datadest = $70000 jmp $60000 org $60000 load $60000 diskbegin: ; real prg-start lea $bfd100,a4 ; get CIAAPRB lea $dff000,a5 ; get customchip-baseadr lea diskbegin(pc),a6 ; get adr of prgstart ;---------- INIT SYSTEM ---------- move.w #$8000,d0 ; set bit 15 move.w $1c(a5),oldint-diskbegin(a6) ; save old intena or.w d0,oldint-diskbegin(a6) ; and set bit 15 move.w $2(a5),olddma-diskbegin(a6) ; save old dma or.w d0,olddma-diskbegin(a6) ; and set bit 15 move.w $10(a5),oldadk-diskbegin(a6) ; save old adk or.w d0,oldadk-diskbegin(a6) ; and set bit 15 subq.w #1,d0 ; d0->$7fff = clearword move.w d0,$9e(a5) ; clear adk move.w d0,$9a(a5) ; forbid interrupts move.w d0,$96(a5) ; stop dmas move.w #$8250,$96(a5) ; allow required dmas move.w #0,$24(a5) ; clear dsklen move.w #$4489,$7e(a5) ; set standard (DOS) SYNC move.w #$9500,$9e(a5) ; set bits for mfm&sync bsr initdrive ; init df0: &step to track 0 bsr gethashtab ; get hash for dir 'DF0:' lea filename(pc),a0 ; adr of filename to load lea datadest,a1 ; adr to load filedata to bsr.s loadfile ; load desired file move.w olddma(pc),$96(a5) ; restore dma-reg move.w oldint(pc),$9a(a5) ; restore int-reg move.w oldadk(pc),$9e(a5) ; restore adk-reg rts ; bye bye ;---------- LOAD A FILE FROM "DF0:"---------- ;----- returns in d0: <>0 = file not found ----- ;----- a0=must contain adr of name/a1=adr to load file to ;---------------------------------------------- loadfile: ; a0 must be adr of filename bsr motoron ; aeehh...turn motor on moveq #0,d7 ; clear work-reg move.b (a0)+,d7 ; get number of chars move.l a0,d6 ; save adr of fileNAME ;---------- CALC HASH OF FILE ---------- move.l d7,d0 ; Hash=Length of name move.l d0,d1 ; get number of chars subq.b #1,d1 ; one less bcoz of dbra moveq #0,d2 ; clear work reg calchashloop: ; let's keep calcin' mulu #13,d0 ; Hash=Hash*13 move.b (a0)+,d2 ; get a char cmp.b #'a',d2 ; char < 'a' blt.s bigchar ; ok ok cmp.b #'z',d2 ; char > 'z' bgt.s bigchar ; ok ok,too sub.b #$20,d2 ; correct it (->big char) bigchar: ; char was a big one add.w d2,d0 ; Hash=Hash+char and.w #$7ff,d0 ; that's it ?! dbra d1,calchashloop ; all chars done ?! divu #72,d0 ; number of entries swap d0 ; want rest ;---------- GET FILEHEADER-BLOCK ---------- lsl.w #2,d0 ; mulu #4,d0 bcoz longwords lea hashtab(pc),a0 ; get hashtab-baseadr move.l (a0,d0.w),d0 ; get blocknumber getfileheader: ; is it the right fileheader divu #11,d0 ; divide blocknumber bsr readtrack ; and read track swap d0 ; get sectornumber ror.w #7,d0 ; ->mulu #512,d0 lea databuffer(pc),a0 ; get data-baseadr add.w d0,a0 ; and go to right sectordata move.l d6,a2 ; get adr of fileNAME lea $1b0(a0),a3 ; get begin of nameinfo cmp.b (a3)+,d7 ; test if same namelength bne.s wrongfileheader ; no->get another fileheader testifrightheader: ; otherwise check name move.b (a3)+,d0 ; get a char cmp.b (a2)+,d0 ; test if char equal bne.s wrongfileheader ; no->get another fileheader subq.w #1,d7 ; all chars compared bne.s testifrightheader ; no->keep comparin' bra.s rightfileheader ; yes->load the blocks wrongfileheader: ; file with same hash move.l $1f0(a0),d0 ; otherwise next fileheader bne.s getfileheader ; <> 0 ->perhaps next header moveq #-1,d0 ; set signal 'file not fou.' rts ; bye bye rightfileheader: ; right fileheader found move.l $10(a0),d0 ; get fileheader-block ;---------- LOAD BLOCKS OF FILE ---------- loadablock: ; load another block divu #11,d0 ; divide blocknumber bsr.s readtrack ; and read track swap d0 ; get sectornumber ror.w #7,d0 ; ->mulu #512,d0 lea databuffer(pc),a0 ; get data-baseadr add.w d0,a0 ; and go to right sectordata move.l $c(a0),d1 ; get number of bytes move.l $10(a0),d0 ; get next blocknumber lea $18(a0),a0 ; go to real data copyblockdata: ; copy real data move.b (a0)+,(a1)+ ; copy a byte subq.w #1,d1 ; one byte more copied bne.s copyblockdata ; all data copied ? tst.w d0 ; all blocks loaded bne.s loadablock ; no->load next one bsr motoroff ; aeehh...turn motor off rts ; file loaded ;---------- SELECT DF0: & STEP TO TRACK 0 ---------- initdrive: ; select df0: and step to 0 ;---------- SELECT DRIVE ---------- or.b #%01111000,(a4) ; all drives off nop ; wait a bit nop ; wait a bit and.b #%11110111,(a4) ; select drive 0 (activelow) ;---------- HEADS ON TRACK 0 ---------- or.b #%00000010,(a4) ; step outwards nop ; wait a bit nop ; wait a bit searchtrack0loop: ; keep steppin' btst #4,$bfe001 ; heads at track 0 ? beq.s track0found ; yes->fine and.b #%11111110,(a4) ; step a bit nop ; wait a bit nop ; wait a bit or.b #%00000001,(a4) ; stop steppin' bsr timer ; let's have a break bra.s searchtrack0loop ; keep steppin' track0found: ; heads at track 0 rts ; everything ready ;---------- LOAD ROOTBLOCK & GET HASH-TAB ---------- gethashtab: ; get 72 hash-entries bsr motoron ; aeehh...turn motor on ;---------- LOAD ROOTBLOCK ---------- move.w #80,d0 ; track to read bsr.s readtrack ; and read it ;---------- GET "PAGES"-HASHTAB ---------- lea databuffer+24(pc),a0 ; go to hashtab-baseadr lea hashtab(pc),a1 ; dest for hashtab moveq #72-1,d0 ; get 72 hashvalues getahash: ; get another value move.l (a0)+,(a1)+ ; save a hash dbra d0,getahash ; all 72 hashes saved ? bsr motoroff ; aeehh...turn motor off rts ; hashtab for 'DF0:' saved ;---------- LOAD & DECODE A TRACK ---------- readtrack: ; read a track (d0=track) movem.l d0-d7/a0-a6,-(a7) ; save regs move.w d0,d2 ; save desired track sub.w track(pc),d2 ; calc difference beq trackloaded ; old track->don't load it bgt.s stepinside ; step to the middle ;---------- STEP OUTWARDS ---------- stepoutside: ; set right step-direction or.b #%00000010,(a4) ; first...step outwards moveq #-2,d1 ; one step=2tracks bra.s checkhead ; check if right head ;---------- STEP TO THE MIDDLE ---------- stepinside: ; set right step-direction and.b #%11111101,(a4) ; step to the middle moveq #2,d1 ; one step=2tracks ;---------- SELECT RIGHT HEAD ---------- checkhead: ; change head ? btst #0,d2 ; test if difference even beq.s letsstep ; yes->don't change head btst #0,d0 ; new track number even ? beq.s lowerhead ; yes->select head 0 and.b #%11111011,(a4) ; otherwise select head 1 addq.w #1,track-diskbegin(a6) ; ->current track+1 bra.s letsstep ; and now start stepping lowerhead: ; new track number even or.b #%00000100,(a4) ; select head 0 subq.w #1,track-diskbegin(a6) ; current track-1 ;---------- STEP TO DESIRED TRACK ---------- letsstep: ; step to right track nop ; wait a bit nop ; wait a bit steploop: ; step to wanted track cmp.w track(pc),d0 ; save new headpos beq.s trackfound ; yeah->now turn on drive and.b #%11111110,(a4) ; step a bit nop ; wait a bit nop ; wait a bit or.b #%00000001,(a4) ; stop steppin' bsr timer ; let's have a break add.w d1,track-diskbegin(a6) ; another step done bra.s steploop ; keep steppin' trackfound: ; on right track now ;---------- TEST IF READY TO LOAD ---------- waitfordrive: ; test if ready for action btst #5,$bfe001 ; test disk-ready-bit bne.s waitfordrive ; set->keep waitin' ;---------- LOAD TRACK ---------- move.w #0,$24(a5) ; clear dsklen lea trackbuffer(pc),a0 ; get dest adr move.l a0,$20(a5) ; and set DSKPT move.w #$9a00,$24(a5) ; set amount of words to move.w #$9a00,$24(a5) ; load and enable diskdma ;---------- WAIT TILL TRACK LOADED ---------- waitfordiskdma: ; test if track loaded btst #1,$1f(a5) ; test dskblk-reqbit beq.s waitfordiskdma ; not set->keep waitin' move.w #0,$24(a5) ; clear dsklen move.w #$0002,$9c(a5) ; clear dskblk-reqbit ;---------- DECODE LOADED DATA ---------- lea trackbuffer(pc),a0 ; get sourceadr moveq #11-1,d6 ; 11 sectors to decode decodeasector: ; decode another sector cmp.w #$4489,(a0)+ ; test if sync bne.s decodeasector ; no->keep searchin' searchnextsync: ; test if any more syncs cmp.w #$4489,(a0) ; test if another sync bne.s nomoresyncs ; no->get sectornumber addq.w #2,a0 ; skip sync bra.s searchnextsync ; and test if another one nomoresyncs: ; all syncs skipped moveq #0,d1 ; clear work-reg move.b 2(a0),d1 ; get sectornumber(odd bits) move.b 6(a0),d2 ; get sectornr (even bits) and.b #$55,d1 ; only want even bits and.b #$55,d2 ; (mask tactbits) add.b d1,d1 ; d1=odd bits of sectornr or.b d2,d1 ; d1=sectornumber ror.w #7,d1 ; mulu #512,d1 lea databuffer+510(pc),a1 ; decode-destadr lea (a1,d1.w),a1 ; go to right sector dest lea 56(a0),a0 ; go to real data lea 510(a0),a0 ; last word of odd bits lea 512(a0),a3 ; last word of even bits bsr.s waitblitter ; wait till blitter ready move.l #$1dd80002,$40(a5) ; ashift=1;descmode moveq #-1,d1 ; =$ffffffff move.l d1,$44(a5) ; don't mask anythink moveq #0,d1 ; no modulo move.w d1,$60(a5) ; bmod/cmod=0 move.l d1,$64(a5) ; amod/dmod=0 move.w #$5555,$70(a5) ; cdat=mask for sourcedata move.l a0,$50(a5) ; write source (odd bits) move.l a3,$4c(a5) ; write source (even bits) move.l a1,$54(a5) ; write dest move.w #[256*64]+1,$58(a5) ; decode 256 words move.l a3,a0 ; get new source dbra d6,decodeasector ; all sectors decoded ? bsr.s waitblitter ; wait till blitter ready trackloaded: ; got data movem.l (a7)+,d0-d7/a0-a6 ; restore regs rts ; bye bye ;---------- SWITCH ENGINE ON ---------- motoron: ; start rotating or.b #%00001000,(a4) ; drive 0 inactive nop ; wait a bit nop ; wait a bit and.b #%01111111,(a4) ; clear enginebit nop ; wait a bit nop ; wait a bit and.b #%11110111,(a4) ; drive 0 active->engine on rts ; motor startin' ;---------- SWITCH ENGINE OFF ---------- motoroff: ; stop rotating or.b #%00001000,(a4) ; drive 0 inactive nop ; wait a bit nop ; wait a bit or.b #%10000000,(a4) ; set enginebit nop ; wait a bit nop ; wait a bit and.b #%11110111,(a4) ; drive 0 active->engine off rts ; motor stoppin' ;---------- WAIT TILL BLITTER FINISHED ---------- waitblitter: ; wait till blitter ready btst #14,2(a5) ; ready for action bne.s waitblitter ; no->keep waintin' rts ; let's go on ;---------- TIMER-ROUT FOR STEPPING-ACTIONS ---------- timer: ; waits ca. 1/100 sec move.b #$00,$bfdf00 ; clear CRB move.b #$7f,$bfdd00 ; clear ICR move.b #$00,$bfd600 ; timer b lowbyte move.b #$1c,$bfd700 ; timer b highbyte move.b #$09,$bfdf00 ; set oneshot/start waittimer: ; wait about 1/100 sec btst #1,$bfdd00 ; test tb-bit ->clear ICR beq.s waittimer ; not set->wait rts ; let's go on ;---------- NOW ONLY THE SHITTY REST ---------- oldint: dc.w 0 olddma: dc.w 0 oldadk: dc.w 0 track: dc.w 0 trackbuffer: blk.w 6656,0 databuffer: blk.b 11*512,0 hashtab: blk.l 72,0 filename: dc.b 6,"Werner" ; number (6) = number of chars of file