NEW AUTO 3,1 *-------------------------------------- XRW.START cld $D8 to flag language card bank 1 (main) lda unitnum get unit number. pha lsr lsr lsr lsr sta XRW.UnitIndex pla and #$7F mask off high bit. sta A2L 0SSS0000 for IO indexing * make sure other drives in other slots are stopped eor XRW.LastUnitUsed same slot as last ? asl beq L59BD lda #$01 sta montimeh L59A6 lda XRW.LastUnitUsed and #$70 tax beq L59BD branch if no previous ever (boot only). jsr XRW.CheckMotorOnX check if previous drive running. beq L59BD branch if stopped. jsr XRW.Wait100usec lda montimeh bne L59A6 L59BD ldx A2L lda IO.D2.Ph0Off,x make sure all motor phases are off lda IO.D2.Ph1Off,x lda IO.D2.Ph2Off,x lda IO.D2.Ph3Off,x lda IO.D2.ReadMode,x turn off write enable X = slot $S0 nop nop lda A4L command #. cmp #$04 is the command allowed ? bcs .9 if not. lda bloknml ldx bloknml+1 stx XRW.ReqTrack calculate block's track and sector. ldy #$05 .11 asl rol XRW.ReqTrack dey bne .11 asl bcc .12 ora #$10 adjust for upper 4 bits of track .12 lsr lsr lsr lsr pha save sector # across call jsr regrwts plx bcs .3 if error inc buf+1 txa adc #$02 jsr regrwts get 2nd half of block dec buf+1 .3 rts .9 lda #MLI.E.IO sec rts *-------------------------------------- * read/write a track/sector regrwts ldy #$01 retry count sty XRW.Recalibrate only one recalibrate per call sta XRW.ReqSector * now check if the motor is on, then start it jsr XRW.CheckMotorOn php save test results lda #$E8 sta montimeh lda unitnum determine drive 1 or 2. cmp XRW.LastUnitUsed same drive used before ? sta XRW.LastUnitUsed save it for next time. php keep results of compare. asl get drive # into carry. lda IO.D2.DrvOn,x turn on the drive. bcc L5362 branch if drive 1 selected. inx select drive 2. L5362 lda IO.D2.DrvSel1,x plp was it the same drive ? beq L5372 yes. plp indicate drive off by setting z-flag. ldy #7 lda #0 150 ms delay before stepping. .1 jsr XRW.Wait100usecA dey bne .1 php now zero flag set. L5372 lda A4L make sure this command needs seeking. beq L537C branch if status check. lda XRW.ReqTrack get destination track jsr XRW.Seek and go to it. * now at desired track. was the motor already on ? L537C plp was motor on ? bne L538E if so, don't wait. * motor was off, wait for it to speed up L537F jsr XRW.Wait100usec wait 100us for each count in montime lda montimeh bmi L537F count up to 0000 * motor should be up to speed, * if it looks stopped then the drive is not present jsr XRW.CheckMotorOn is drive present ? beq hndlerr branch if no drive * now check: if it is not the status disk command, * locate the correct sector for this operation L538E lda A4L get command # beq L53FD if 0 then status command lsr set carry = 1 for read, 0 for write. bcs L5398 must prenibblize for write jsr XRW.PreNibble L5398 ldy #64 sty XRW.RetryCnt L539D jsr XRW.ReadAddr read next address field. bcc L53BE branch if read ok. L53A4 dec XRW.RetryCnt one less chance. bpl L539D branch to retry. lda #MLI.E.IO anticipate a bad drive error. dec XRW.Recalibrate can only recalibrate once. bne hndlerr * lda XRW.CurrentTrack lda #0 pha save track * clc * adc #12 pretend track is 8 > curtrk lda #40 ldy #64 sty XRW.RetryCnt reset retries to 64 max. bra L53CC always. * have now read an address field. make sure this is * the correct track, sector and volume. L53BE ldy XRW.AddrField.T cpy XRW.CurrentTrack beq L53D5 ok * recalibrating from this track lda XRW.CurrentTrack preserve destination track pha tya L53CC ldy XRW.UnitIndex get index to drive # sta XRW.D2Trk-1,y set the slot dependent track location pla jsr XRW.Seek bra L539D * drive is on right track, check volume mismatch L53D5 lda XRW.AddrField.S is this the right sector ? cmp XRW.ReqSector bne L53A4 no, try another sector. lda A4L read or write ? lsr the carry will tell. bcc L53F4 branch if write jsr XRW.Read bcs L53A4 if bad read L53E7 lda #$00 .HS D0 bne branch never taken (skip 1 byte) hndlerr sec ldx A2L slot offset bit IO.D2.DrvOff,x turn off rts *-------------------------------------- L53F4 jsr XRW.Write statdne bcc L53E7 if no errors. lda #MLI.E.WRTPROT disk write protected. bne hndlerr always L53FD ldx A2L lda IO.D2.ReadProt,x test for write protected lda IO.D2.ReadMode,x rol write protect-->carry-->bit 0=1 lda IO.D2.RData,x keep in read mode bra statdne *-------------------------------------- * determine if motor is stopped * * if stopped, controller's shift register will not be changing. * return y = 0 and zero flag set if it is stopped. *-------------------------------------- XRW.CheckMotorOn ldx A2L XRW.CheckMotorOnX ldy #0 init loop counter. .1 lda IO.D2.RData,x read the shift register. jsr .9 delay pha pla more delay. cmp IO.D2.RData,x has shift reg changed ? bne .9 yes, motor is moving. lda #MLI.E.NODEV anticipate error. dey no, dec retry counter bne .1 and try 256 times. .9 rts *-------------------------------------- * preniblize subroutine (16 sector format) * * converts 256 bytes of user data in (buf) into 6 bit nibls in nbuf2. * high 6 bits are translated directly by the write routines. * * on entry: buf is 2-byte pointer to 256 bytes of user data. * * on exit: a,x,y undefined. write routine modified to do direct conversion * of high 6 bits of user's buffer data. *-------------------------------------- XRW.PreNibble lda buf self-modify the addresses because of ldy buf+1 the fast timing required. clc all offsets are minus $AA. adc #$02 the highest set is buf+$AC. bcc L58FA branch if no carry, iny otherwise add carry to high address. L58FA sta prn3+1 self mod 3 sty prn3+2 sec sbc #$56 middle set is buf+$56. bcs L5906 branch if no borrow, dey otherwise deduct from high. L5906 sta prn2+1 self mod 2 sty prn2+2 sec sbc #$56 low set is exactly buf bcs L5912 dey L5912 sta prn1+1 self mod 1 sty prn1+2 ldy #$AA count up to 0. prn1 lda $1000,y warning: self modified. get byte from lowest group. and #$03 strip high 6 bits. tax index to 2 bit equivalent. lda XRW.0000XX00,x pha save pattern prn2 lda $1056,y warning: self modified. get byte from middle group. and #$03 tax pla restore pattern. ora XRW.00XX0000,x combine 2nd group with 1st. pha save new pattern. prn3 lda $10AC,y warning: self modified. get byte from highest group. and #$03 tax pla restore new pattern ora XRW.XX000000,x and form final nibl. pha tya eor #$FF tax pla sta nbuf2,x save in nibl buffer. iny inc to next set. bne prn1 loop until all $56 nibls formed. ldy buf now prepare data bytes for write16 subr. dey prepare end address. sty A2H lda buf sta wrefd1+1 warning: the following storage addresses beq L595F starting with 'wref' are refs into code eor #$FF space, changed by this routine. tay index to last byte of page in (buf). lda (buf),y pre-niblize the last byte of the page iny with the first byte of the next page. eor (buf),y and #$FC tax lda XRW.FC2Nib,x get disk 7-bit nible equivalent. L595F sta pch beq L596F branch if data to be written is page aligned. lda A2H check if last byte is even lsr or odd address. shift even/odd -> carry. lda (buf),y if even, then leave intact. bcc L596D branch if odd. iny if even, then pre-xor with byte 1. eor (buf),y L596D sta A1L save result for write routine. L596F ldy #$FF index to last byte of data to write. lda (buf),y to be used as a checksum. and #$FC strip extra bits sta A1H and save it. ldy buf+1 now modify address references to sty wrefa1+2 user data. sty wrefa2+2 iny sty wrefa3+2 sty wrefa4+2 sty wrefa5+2 sty wrefa6+2 ldx A2L and lastly, index references to stx wrefd2+1 controller. stx wrefd3+1 stx wrefd4+1 stx wrefd5+1 rts *-------------------------------------- * write subroutine (16 sector format) * * writes data from nbuf1 and buf. first nbuf2, high to low then direct * from (buf), low to high. assumes 1 usec cycle time. self modified code !! * * on entry: x = slotnum times 16 * * on exit: carry set if error (write protect violation). * if no error, acc=uncertain, x=unchanged, y=0, carry clear. *-------------------------------------- XRW.Write sec anticipate write protect error lda IO.D2.ReadProt,x lda IO.D2.ReadMode,x sense write protect flag bpl .1 jmp wexit exit if write protected * timing is critical. a one micro-second cycle time is assumed. * number in () is how many micro-seconds per instruction or subroutine .1 lda nbuf2 sta pcl lda #$FF sync data. sta IO.D2.WriteMode,x (5) goto write mode ora IO.D2.WShift,x (4) ldy #$04 (2) for five nibls nop (2) pha (3) pla (4) wsync pha (3) exact timing. pla (4) exact timing. jsr wnibl7 (13,9,6) write sync. dey (2) bne wsync (3-) must not cross page ! lda #$D5 (2) 1st data mark jsr wnibl9 (15,9,6) lda #$AA (2) 2nd data mark jsr wnibl9 (15,9,6) lda #$AD (2) 3rd data mark jsr wnibl9 (15,9,6) tya (2) zero checksum ldy #$56 (2) nbuf2 index bne L583D (3) branch always * total time in this write byte loop must = 32us !!! L583A lda nbuf2,y (4) prior 6-bit nibl *L583D eor nbuf2-1,y (5) xor with current (4+1 : PAGE CROSS) L583D eor nbuf2-1,y (4) xor with current (NO MORE PAGE CROSS) tax (2) index to 7-bit nibl lda XRW.FC2Nib,x (4) must not cross page boundary * ldx A2L (3) restore slot index ldx >A2L (4) absolute reference to zero page sta IO.D2.WLoad,x (5) store encoded byte lda IO.D2.WShift,x (4) handshake dey (2) bne L583A (3-) must not cross page boundary * end of write byte loop lda pcl (3) get prior nibl (from nbuf2) wrefd1 ldy #$00 (2) warning: load value modified by prenib. wrefa1 eor $1000,y (4) warning: address modified by prenib. and #$FC (2) strip low 2 bits tax (2) index to nibl table lda XRW.FC2Nib,x (4) wrefd2 ldx #$60 (2) warning: value modified by prenib. sta IO.D2.WLoad,x (5) write nibl lda IO.D2.WShift,x (4) handshake wrefa2 lda $1000,y (4) prior nibl. warning: address modified by prenib. iny (2) all done with this page ? bne wrefa1 (3-) loop until page end. lda pch (3) get next (precalculated & translated) nibl. beq L58C0 (2+) branch if code written was page aligned. lda A2H (3) get byte address of last byte to be written. beq L58B3 (2+) branch if only 1 byte left to write. lsr (2) test for odd or even last byte (carry set/clear) lda pch (3) restore nibl to acc. sta IO.D2.WLoad,x (5) lda IO.D2.WShift,x (4) lda A1L (3) = byte 0 of 2nd page xor'd with byte 1 if nop (2) above test set carry. iny (2) y=1 bcs L5899 (2+) branch if last byte to be odd. wrefa3 eor $1100,y (4) warning: address modified by prenib. and #$FC (2) strip low 2 bits. tax (2) index to nibl table lda XRW.FC2Nib,x (4) get nibl wrefd3 ldx #$60 (2) restore slot index. warning: modified by prenib sta IO.D2.WLoad,x (5) lda IO.D2.WShift,x (4) wrefa4 lda $1100,y (4) warning: modified by prenib iny (2) got prior nibl, point to next wrefa5 eor $1100,y (4) warning: modified by prenib L5899 cpy A2H (3) set carry if this is the last nibl and #$FC (2) strip low 2 bits tax (2) lda XRW.FC2Nib,x (4) wrefd4 ldx #$60 (2) restore slot. warning: modified by prenib sta IO.D2.WLoad,x (5) lda IO.D2.WShift,x (4) wrefa6 lda $1100,y (4) get prior nibl. warning: modified by prenib iny (2) bcc wrefa3 (3-) branch if not the last. bcs L58B1 (3) waste 3 cycles, branch always. L58B1 bcs L58C0 (3) branch always. L58B3 lda >pch (4) absolute reference to zero page sta IO.D2.WLoad,x (5) lda IO.D2.WShift,x (4) pha (3) waste 14 micro-seconds total pla (4) pha (3) pla (4) L58C0 ldx A1H (3) use last nibl (anded with $FC) for checksum lda XRW.FC2Nib,x (4) wrefd5 ldx #$60 (2) restore slot. warning: modified by prenib sta IO.D2.WLoad,x (5) lda IO.D2.WShift,x (4) ldy #$00 (2) set y = index end mark table. pha (3) waste another 11 micro-seconds pla (4) nop (2) nop (2) L58D3 lda XRW.EndDataMark,y (4) dm4, dm5, dm6 and turn off byte. jsr wnibl (15,6) write it iny (2) cpy #$04 (2) have all end marks been written ? bne L58D3 (3) if not. clc (2,9) wexit lda IO.D2.ReadMode,x out of write mode lda IO.D2.WShift,x to read mode. rts return from write. * 7-bit nibl write subroutines wnibl9 clc (2) 9 cycles, then write. wnibl7 pha (3) 7 cycles, then write. pla (4) wnibl sta IO.D2.WLoad,x (5) nibl write ora IO.D2.WShift,x (4) clobbers acc, not carry rts (6) *-------------------------------------- * delays a specified number of 100 usec intervals for motor timing. * on entry: acc holds number of 100 usec intervals to delay. * on exit: acc = 0, x = 0, y = unchanged, carry set. * montimel, montimeh are incremented once per 100 usec interval * for motor on timing. *-------------------------------------- XRW.Wait100usec lda #1 XRW.Wait100usecA sec (2) .1 ldx #17 (2) .2 dex (2) bne .2 (3) inc montimel (6) bne .3 (3) inc montimeh (6) .3 sbc #1 bne .1 rts *-------------------------------------- * read subroutine (16-sector format) * * reads encoded bytes into nbuf1 and nbuf2. * first reads nbuf2 high to low, then nbuf1 low to high. * on entry: x=slot# times $10, read mode * on exit: carry set if error, else if no error: * acc=$AA, x=unchanged, y=0, carry clear. * observe 'no page cross' on some branches !! *-------------------------------------- XRW.Read txa get slot # ora #$8C prepare mods to read routine. sta rd4+1 warning: the read routine is sta rd5+1 self modified !! sta rd6+1 sta rd7+1 sta rd8+1 lda buf modify storage addresses also ldy buf+1 sta ref3+1 sty ref3+2 sec sbc #$54 bcs L571F branch if no borrow dey L571F sta ref2+1 sty ref2+2 sec sbc #$57 bcs L572B branch if no borrow dey L572B sta ref1+1 sty ref1+2 ldy #$20 32 tries to find L5733 dey beq L576D branch if can't find data header marks L5736 lda IO.D2.RData,x bpl L5736 L573B eor #$D5 1st data mark bne L5733 nop delay L5740 lda IO.D2.RData,x bpl L5740 cmp #$AA 2nd data mark. bne L573B if not, check for 1st again nop L574A lda IO.D2.RData,x bpl L574A cmp #$AD 3rd data mark bne L573B if not, check for data mark 1 again ldy #$AA lda #$00 L5757 sta pcl use z-page for keeping checksum rd4 ldx IO.D2.RData+$60 warning: self modified bpl rd4 lda XRW.Nib2FC-$96,x sta nbuf2-$AA,y save the two-bit groups in nbuf. eor pcl update checksum. iny next position in nbuf. bne L5757 loop for all $56 two-bit groups. ldy #$AA now read directly into user buffer. bne rd5 always taken. L576D sec error rts ref1 sta $1000,y warning: self modified rd5 ldx IO.D2.RData+$60 warning: self modified bpl rd5 eor XRW.Nib2FC-$96,x get actual 6-bit data from dnib table. ldx nbuf2-$AA,y get associated two-bit pattern eor dnibl2,x and combine to form whole byte. iny bne ref1 loop for $56 bytes. pha save for now, no time to store... and #$FC strip low bits. ldy #$AA prepare for next $56 bytes rd6 ldx IO.D2.RData+$60 warning: self modified bpl rd6 eor XRW.Nib2FC-$96,x ldx nbuf2-$AA,y eor dnibl3,x ref2 sta $1000,y warning: self modified iny bne rd6 loop unil this group of $56 read rd7 ldx IO.D2.RData+$60 warning: self modified bpl rd7 and #$FC ldy #$AC last group is $54 long L57A5 eor XRW.Nib2FC-$96,x ldx nbuf2-$AC,y eor dnibl4,x combine to form full byte ref3 sta $1000,y warning: self modified rd8 ldx IO.D2.RData+$60 warning: self modified bpl rd8 iny bne L57A5 and #$FC eor XRW.Nib2FC-$96,x checksum ok ? bne L57CC error if not. ldx A2L test end marks. L57C2 lda IO.D2.RData,x bpl L57C2 cmp #$DE clc beq L57CD branch if good trailer L57CC sec L57CD pla place last byte into user buffer ldy #$55 sta (buf),y rts *-------------------------------------- * fast seek subroutine * A = desired track * XRW.CurrentTrack = current rack * * montimel,h are incremented by the # of 100us quantums required by seek for motor on time overlap. * variables used: XRW.CurrentTrack, A2L, montimel, montimeh *-------------------------------------- XRW.Seek ldx XRW.UnitIndex pha save target track jsr XRW.Trk2Qtrk sta XRW.TargetQTrack lda XRW.D2Trk-1,x jsr XRW.Trk2Qtrk sta XRW.CurrentQTrack pla sta XRW.CurrentTrack sta XRW.D2Trk-1,x will be current track at the end ldy #0 .1 ldx XRW.CurrentQTrack tya beq .2 txa jsr XRW.PhaseOff .2 cpx XRW.TargetQTrack beq .8 bcs .3 inx CC, CurrentQTrack>TargetQTrack, must move in .HS B0 BCS .3 dex CS, CurrentQTrack0000FE * dnibl3 abcdef-->0000DC * dnibl4 abcdef-->0000BA * page align the following tables: *-------------------------------------- * FC-bits to nibble conversion table (256 bytes) * * codes with more than one pair of adjacent zeroes * or with no adjacent ones (except B7) are excluded. *-------------------------------------- dnibl2 .HS 00 dnibl3 .HS 00 dnibl4 .HS 00 XRW.FC2Nib .HS 96 .HS 02000097 .HS 0100009A .HS 0300009B .HS 0002009D .HS 0202009E .HS 0102009F .HS 030200A6 .HS 000100A7 .HS 020100AB .HS 010100AC .HS 030100AD .HS 000300AE .HS 020300AF .HS 010300B2 .HS 030300B3 .HS 000002B4 .HS 020002B5 .HS 010002B6 .HS 030002B7 .HS 000202B9 .HS 020202BA .HS 010202BB .HS 030202BC .HS 000102BD .HS 020102BE .HS 010102BF .HS 030102CB .HS 000302CD .HS 020302CE .HS 010302CF .HS 030302D3 .HS 000001D6 .HS 020001D7 .HS 010001D9 .HS 030001DA .HS 000201DB .HS 020201DC .HS 010201DD .HS 030201DE .HS 000101DF .HS 020101E5 .HS 010101E6 .HS 030101E7 .HS 000301E9 .HS 020301EA .HS 010301EB .HS 030301EC .HS 000003ED .HS 020003EE .HS 010003EF .HS 030003F2 .HS 000203F3 .HS 020203F4 .HS 010203F5 .HS 030203F6 .HS 000103F7 .HS 020103F9 .HS 010103FA .HS 030103FB .HS 000303FC .HS 020303FD .HS 010303FE .HS 030303FF *-------------------------------------- XRW.LEN .EQ *-XRW.START MAN SAVE usr/src/prodos.fx/prodos.s.xrw LOAD usr/src/prodos.fx/prodos.s ASM