 ttl UniFLEX Disk Formatter
 sttl DMAF-2 8" Floppy Disk Bootstrap
 pag
 info Bootstrap for S09/DMF2 Version 2.00; 5/13/83

* UniFLEX Bootstrap Loader for 6809 DMAF

 global uboot,ubflgs

* Special locations

corcnt equ $13
lstmem equ $14

DATMAP equ $FFFA Map for $A000
BLKHOLE equ $F3 Black hole in map
DATSENSE equ $FF Sense of data in DAT

*
old_org equ $B000 org of loader as loaded by ROM
new_org equ $B800 new org of loader

* Buffers

 base new_org+512
buffer rmb 512
map rmb 512
* Equates
ffmap equ 17 file map offset in fdn
bhxfr equ 10 transfer address offset in header
BHDSIZ equ 24 binary file header size

* System equates for single sector read

SECLEN equ $FFFF-512 com of sector length
BUSY equ 1 busy mask
DMF2ADR equ $F000 Base address for DMF2 controller
drvreg equ DMF2ADR+$24 drive register
comreg equ DMF2ADR+$20 commmand register
trkreg equ DMF2ADR+$21 track register
secreg equ DMF2ADR+$22 sector register
datreg equ DMF2ADR+$23 data register
addreg equ DMF2ADR+$00 dma address register
cntreg equ DMF2ADR+$02 dma count register
ccreg equ DMF2ADR+$10 dma register
prireg equ DMF2ADR+$14 dma priority register
latch equ DMF2ADR+$40 dma address latch
RDCMND equ $8C read command
SKCMND equ $19 seek command

* Temporary storage

 base $00E0
btdate rmb 4
direct rmb 1
mapptr rmb 2
entrys rmb 2
xfradr rmb 2
sdslct rmb 1

 data

********************************************
* Start of program
********************************************

********* org $B000

* Lookup "uniflex" in directory

uboot lbra uboot0 skip disk type bytes

ubflgs fcb 0,0
**************************************************
dside equ new_org+$0004
dnsity equ new_org+$0003
**************************************************
*
* Relocate loader from "old_org" to "new_org"
*
uboot0 ldx #old_org
 ldu #new_org
00 ldd ,x++ move loader text
 std ,u++
 cmpx #old_org+512
 blo 00b
 lbra (uboot1-old_org)+new_org
*
uboot1 lda $010A check block $A000 mapped in
 cmpa #BLKHOLE black hole?
 bne uboot2
 dec corcnt decrease number of pages available
 ldx lstmem pick up last page pointer
 lda ,-x get a page
 stx lstmem
 sta $010A set up map
 sta DATMAP
uboot2 ldd #1 root directory fdn no.
 lbsr fdnblk read in fdn
 ldd 7,y find size of directory
 lbsr divby8
 lsra
 rorb
 std entrys save entry count
read1 lbsr rdblk read data block
 lbne noboot exit if error
lookup leax 2,u point to filespec
 ldd 0,u check for deleted entry
 beq nxtent skip deleted files
 leay btname,pcr point to boot file name
 ldb #14 set name length
cmpnam lda 0,x+
 cmpa 0,y+ is this boot file entry?
 bne nxtent if not, skip to next
 decb
 bne cmpnam
 ldd 0,u found it, get fdn
 bra load go load uniflex
nxtent ldx entrys
 leax -1,x decrement count
 stx entrys end of directory?
 beq noboot error if so
 leau 16,u point to next entry
 cmpu #buffer+512 past current block?
 bne lookup check entry if not
 bra read1 else, get another block

* Load UniFLEX

load bsr fdnblk read in uniflex fdn
 ldx mapptr point to fdn map
 leax 13*3,x skip map
 ldd ,x++ copy FDN date
 std btdate
 ldd ,x++
 std btdate+2
 bsr rdblk read 1st block of the file
 bne noboot exit if error
 ldd bhxfr,u get transfer address
 std xfradr save it
 leau BHDSIZ,u skip binary file header
getrc1 bsr getchr get record length in x
 tfr b,a
 bsr getchr
 cmpd #0 terminator?
 beq done start uniflex if so
 tfr d,x
 bsr getchr get load address in y
 tfr b,a
 bsr getchr
 tfr d,y
getrc2 bsr getchr get a data byte
 stb 0,y+ put in memory
 leax -1,x decrement the count
 bne getrc2 loop if not end of record
 bra getrc1 else, get next record

* Uniflex is loaded, begin execution

done ldy $5002 boot date vector
 ldd btdate copy date
 std ,y++
 ldd btdate+2
 std ,y++
 jmp [xfradr] jump to transfer address

* Divide contents of D by 8

divby8 lsra
 rorb
 lsra
 rorb
 lsra
 rorb
 rts

* Get single character from binary file

getchr cmpu #buffer+512 more data in buffer?
 bne getch2 skip if so
 pshs a,x,y
 bsr rdblk else, read another block
 puls a,x,y
 bne nbootx exit if error
getch2 ldb 0,u+ get character, advance ptr
 rts

* Uniflex file was not found

nbootx puls d fix stack
noboot rts return to monitor ROM

* Read fdn specified in D

fdnblk pshs d save fdn number
 addd #15 convert to block number
 bsr divby8
 lbsr mread read a block
 puls d restore fdn number
 bne nbootx exit if error
 decb calculate buffer offset
 andb #$07
 lda #64
 mul offset=(fdn&7)*64
 addd #map
 tfr d,y fdn pointer in y
 addd #9 point to ffmap
 std mapptr save map pointer
 lda #10 get direct block count
 sta direct initialize indirect flag
 rts

* Read a block from file

rdblk tst direct a direct block?
 beq chgind change to indirect
 dec direct dec. direct count
 ldx mapptr get file map pointer
 ldd 1,x block address in d
 leax 3,x point to next
 stx mapptr
 bsr blkts convert block to trk & sct
 ldx #buffer setup buffer address
 bra xread read the sector

chgind ldx mapptr get file map pointer
 ldd 1,x address of indirect block
 bsr mread read block of indirects
 bne nbootx exit if error
 stu mapptr reset file map pointer
 lda #128 set new direct count
 sta direct
 bra rdblk now read data block

* Convert block number in D to track & sector

blkts clr sdslct assume side 0
 tst dnsity check for double density
 bne dbkts skip if so
 pshs b
 bsr divby8 get track number in A
 tfr b,a
 puls b
 andb #$07 get sector number in B
 incb no sector 0
 tst dside double sided disk?
 beq blkts8 skip if not
 lsra correct the track number
 bcc blkts8 skip if on side 0
 addb #8 else fix sector number
 bra blkts6
dbkts pshs b
 lsra divide block number by 16
 rorb
 lsra
 rorb
 lsra
 rorb
 lsra
 rorb
 tfr b,a get track
 puls b
 andb #$f
dbkts4 incb no sector 0
 tst dside double sided?
 beq blkts8 skip if not
 lsra correct the track number
 bcc blkts8 skip if on side 0
 addb #16 else, fix sector number
blkts6 inc sdslct show side #1
blkts8 rts

* Read the specified map block

mread bsr blkts convert block to trk & sct
 ldx #map address of buffer for block

****************************************************

* Read a single sector

xread stb secreg set sector
 leau 0,x save buffer start
 cmpa trkreg check new track
 beq seek4
 sta datreg setup wd reg
 lbsr del delay
 lda #SKCMND setup command
 sta comreg issue command
 lbsr del delay
seek4 bsr xwait
* select proper side and density
 ldb #$81 default to side 0 & drive 0
 tst sdslct should it be side 1?
 beq seek6 skip if not
 orb #$10 set side 1
seek6 tst dnsity see if double density
 bne seek8 skip if so
 orb #$20 set single density
seek8 comb
 stb drvreg do select
config bsr altadr
 coma complement address
 comb
 std addreg
 ldx #SECLEN get char count
 stx cntreg set in register
 ldb #$FF set channel
 stb ccreg
 ldb #$FE enable channel 0
 lda #RDCMND setup command

* do dma transfer

dodma stb prireg set register
 sta comreg send disk command
 bsr del
 ldx #$E000 set counter
dodma2 tst ccreg check status
 bpl dodma4 finished?
 dex dec the count
 bne dodma2 loop til done
dodma4 ldx #$FFFF clear dma channel
 stx prireg
 bsr xwait xwait til finished
dodma7 bitb #$FC check for errors
 rts return

* convert address for dmaf

altadr lda $010B get memory map value
 tfr a,b
 lsra get upper half
 lsra
 lsra
 lsra
 ora #$10 set dmaf interrupt latch
 sta latch setup dmaf latch
 eorb #DATSENSE
 lslb get lower half
 lslb
 lslb
 lslb
 pshs b save it
 tfr x,d get address
 anda #$0F mask off upper 4 bits
 ora 0,s+ replace with map bits
 rts return with address in d

* xwait

xwait ldb comreg get status
 bitb #BUSY check if busy
 bne xwait
xwait2 rts  return

* delay

del lda #$20
del2 deca
 bne del2
 rts

****************************************************


* filename for booting

btname fcc 'uniflex'
 fcb 0,0,0,0,0,0,0

 if (*-uboot)>512
 err Bootstrap Overflow!
 else
 rzb 512-(*-uboot)
 endif
 end
