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[/] [System09/] [rev_86/] [src/] [boot/] [bootcf8.asm] - Blame information for rev 161

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Line No. Rev Author Line
1 59 davidgb
*******************************************************
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*
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* Bootstrap FLEX Loader
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*
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* SBUG1.8 loads the bootstap loader at $C000
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* however the Flex adaption manual has the
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* bootstrap loader residing at $C100
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*
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******************************************************
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*
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* Equates
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*
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STACK   EQU $C0FF
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SCTBUF  EQU $C300
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*
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* Start of Utility
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*
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        ORG $C000
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BOOT    BRA LOAD0
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        FCB 0,0,0
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TRK     FCB 0        File start track
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SCT     FCB 0        File start sector
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DNS     FCB 0        Density Flag (not used)
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TADR    FDB $C000    Transfer address
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LADR    FDB 0        Load Address
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DRVNUM  FCB 0        Drive number 0
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*
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LOAD0   LDS  #STACK   Set up stack
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        LDD  TRK      Set up start track and sector
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        STD  SCTBUF
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        LDY  #SCTBUF+256
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*
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* Perform actual file load
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*
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LOAD1   BSR GETCH    Get acharcater
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        CMPA #$02    Data record hearder ?
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        BEQ  LOAD2   Skip, is so
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        CMPA #$16    Xfr address hearder ?
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        BNE LOAD1    Loop if neither
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*
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* Get transfer address
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*
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        BSR  GETCH
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        STA  TADR
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        BSR  GETCH
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        STA  TADR+1
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        BRA  LOAD1
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*
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* Load data record
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*
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LOAD2  BSR  GETCH  Get load address
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       STA  LADR
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       BSR  GETCH
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       STA  LADR+1
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       BSR  GETCH  Get Bytes count
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       TFR  A,B
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       TSTB
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       BEQ  LOAD1 Loop if count = 0
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       LDX  LADR  Get load address
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LOAD3  PSHS B,X
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       BSR  GETCH  Get data character
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       PULS B,X
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       STA  ,X+    Store at load address
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       DECB
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       BNE  LOAD3  Loop until count = 0
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       BRA  LOAD1
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*
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* Get Character routine
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* Reads a sector if needed
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*
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GETCH  CMPY #SCTBUF+256 out of data ?
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       BNE  GETCH4      Go read Character if not
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GETCH2 LDX  #SCTBUF     Point to buffer
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       LDD  0,X         Get forward Link
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       BEQ  GO          if zero, file is loaded
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       BSR  READ        Read next sector
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       BNE  BOOT        start over if error
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       LDY  #SCTBUF+4   Point past link
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GETCH4 LDA  ,Y+         Else, get a character
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       RTS
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*
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* File is loaded, Jump to it
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*
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GO     JMP  [TADR]      Jump to transfer address
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*
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** FLEX 9 COMPACT FLASH DISK DRIVERS
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*
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* FOR SYS09BUG 1.2 ON THE BURCHED B5-X300
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* WITH I/O MAPPED AT $XE000
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* AND ROM MAPPED AT $XF000
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* THE BURCHED B5-X300 HAS 256KBYTES OF SRAM
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* THE FIRST 64K IS USED BY FLEX,
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* THE SECOND 192K MAY BE USED AS A RAM DISK
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*
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*
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IMASK  EQU $10     IRQ MASK CC
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FMASK  EQU $40     FIRQ MASK CC
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DATREG EQU $FFF0   DAT REGISTERS
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*
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CF_BASE    EQU $E040
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CF_DATA    EQU CF_BASE+0
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CF_ERROR   EQU CF_BASE+1 ; read error
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CF_FEATURE EQU CF_BASE+1 ; write feature
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CF_SECCNT  EQU CF_BASE+2
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CF_SECNUM  EQU CF_BASE+3
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CF_CYLLO   EQU CF_BASE+4
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CF_CYLHI   EQU CF_BASE+5
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CF_HEAD    EQU CF_BASE+6
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CF_STATUS  EQU CF_BASE+7 ; read status
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CF_COMAND  EQU CF_BASE+7 ; write command
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*
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* Command Equates
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*
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CMDREAD    EQU $20 ; Read Single sector
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CMDWRITE   EQU $30 ; Write Single sector
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CMDFEATURE EQU $EF
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FEAT8BIT   EQU $01 ; enable 8 bit transfers
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HEADLBA    EQU $E0
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*
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* Status bit equates
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*
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BSY        EQU $80
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DRDY       EQU $40
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DRQ        EQU $08
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ERR        EQU $01
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*
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* RESTORE DISK DRIVER (SEEK TRACK 00)
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*
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RESTR1 CLR  DRVNUM
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       CLRA           ; Track 0
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       LDB  #$01     ; Sector 1
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*
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* Seek track and sector
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* A holds track number (0 - ??)
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* B holds sector number (1 - ??)
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* Sector numbers starts from 1
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* subtract 1 to start from sector 0 on CF
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*
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SEEKTS DECB
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       STB  CF_SECNUM
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       STA  CF_CYLLO
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       LDB  DRVNUM
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       STB  CF_CYLHI
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       LDB  #$01
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       STB  CF_SECCNT
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       CLRB
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WARMD1 RTS
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*
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* READ SECTORS FROM CF
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*
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*
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READ   BSR  SEEKTS
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       LDA  #CMDREAD ; IDE READ MULTIPLE
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       STA  CF_COMAND
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       BSR  WAITRDY
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*
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* READ LOOP
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*
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       CLRB
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RDLP1  BSR  WAITDRQ
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       LDA  CF_DATA
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       STA  ,X+
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       DECB
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       BNE  RDLP1
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*
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       CLRB
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RDLP2  BSR  WAITDRQ
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       LDA  CF_DATA
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       DECB
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       BNE  RDLP2
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*
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       BSR  WAITRDY
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       CLRB
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       RTS
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*
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* WAIT UNTIL READY
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*
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WAITRDY LDA  CF_STATUS
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        BITA #BSY
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        BNE  WAITRDY
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        LDA  CF_STATUS
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        BITA #DRDY
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        BEQ  WAITRDY
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        RTS
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*
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* WAIT FOR DATA REQUEST
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*
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WAITDRQ LDA  CF_STATUS
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        BITA #DRQ
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        BEQ  WAITDRQ
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        RTS
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*
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        END

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