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[/] [System09/] [trunk/] [src/] [boot/] [bootcf8.asm] - Rev 203
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*******************************************************
*
* Bootstrap FLEX Loader
*
* SBUG1.8 loads the bootstap loader at $C000
* however the Flex adaption manual has the
* bootstrap loader residing at $C100
*
******************************************************
*
* Equates
*
STACK EQU $C0FF
SCTBUF EQU $C300
*
* Start of Utility
*
ORG $C000
BOOT BRA LOAD0
FCB 0,0,0
TRK FCB 0 File start track
SCT FCB 0 File start sector
DNS FCB 0 Density Flag (not used)
TADR FDB $C000 Transfer address
LADR FDB 0 Load Address
DRVNUM FCB 0 Drive number 0
*
LOAD0 LDS #STACK Set up stack
LDD TRK Set up start track and sector
STD SCTBUF
LDY #SCTBUF+256
*
* Perform actual file load
*
LOAD1 BSR GETCH Get acharcater
CMPA #$02 Data record hearder ?
BEQ LOAD2 Skip, is so
CMPA #$16 Xfr address hearder ?
BNE LOAD1 Loop if neither
*
* Get transfer address
*
BSR GETCH
STA TADR
BSR GETCH
STA TADR+1
BRA LOAD1
*
* Load data record
*
LOAD2 BSR GETCH Get load address
STA LADR
BSR GETCH
STA LADR+1
BSR GETCH Get Bytes count
TFR A,B
TSTB
BEQ LOAD1 Loop if count = 0
LDX LADR Get load address
LOAD3 PSHS B,X
BSR GETCH Get data character
PULS B,X
STA ,X+ Store at load address
DECB
BNE LOAD3 Loop until count = 0
BRA LOAD1
*
* Get Character routine
* Reads a sector if needed
*
GETCH CMPY #SCTBUF+256 out of data ?
BNE GETCH4 Go read Character if not
GETCH2 LDX #SCTBUF Point to buffer
LDD 0,X Get forward Link
BEQ GO if zero, file is loaded
BSR READ Read next sector
BNE BOOT start over if error
LDY #SCTBUF+4 Point past link
GETCH4 LDA ,Y+ Else, get a character
RTS
*
* File is loaded, Jump to it
*
GO JMP [TADR] Jump to transfer address
*
** FLEX 9 COMPACT FLASH DISK DRIVERS
*
* FOR SYS09BUG 1.2 ON THE BURCHED B5-X300
* WITH I/O MAPPED AT $XE000
* AND ROM MAPPED AT $XF000
* THE BURCHED B5-X300 HAS 256KBYTES OF SRAM
* THE FIRST 64K IS USED BY FLEX,
* THE SECOND 192K MAY BE USED AS A RAM DISK
*
*
IMASK EQU $10 IRQ MASK CC
FMASK EQU $40 FIRQ MASK CC
DATREG EQU $FFF0 DAT REGISTERS
*
CF_BASE EQU $E040
CF_DATA EQU CF_BASE+0
CF_ERROR EQU CF_BASE+1 ; read error
CF_FEATURE EQU CF_BASE+1 ; write feature
CF_SECCNT EQU CF_BASE+2
CF_SECNUM EQU CF_BASE+3
CF_CYLLO EQU CF_BASE+4
CF_CYLHI EQU CF_BASE+5
CF_HEAD EQU CF_BASE+6
CF_STATUS EQU CF_BASE+7 ; read status
CF_COMAND EQU CF_BASE+7 ; write command
*
* Command Equates
*
CMDREAD EQU $20 ; Read Single sector
CMDWRITE EQU $30 ; Write Single sector
CMDFEATURE EQU $EF
FEAT8BIT EQU $01 ; enable 8 bit transfers
HEADLBA EQU $E0
*
* Status bit equates
*
BSY EQU $80
DRDY EQU $40
DRQ EQU $08
ERR EQU $01
*
* RESTORE DISK DRIVER (SEEK TRACK 00)
*
RESTR1 CLR DRVNUM
CLRA ; Track 0
LDB #$01 ; Sector 1
*
* Seek track and sector
* A holds track number (0 - ??)
* B holds sector number (1 - ??)
* Sector numbers starts from 1
* subtract 1 to start from sector 0 on CF
*
SEEKTS DECB
STB CF_SECNUM
STA CF_CYLLO
LDB DRVNUM
STB CF_CYLHI
LDB #$01
STB CF_SECCNT
CLRB
WARMD1 RTS
*
* READ SECTORS FROM CF
*
*
READ BSR SEEKTS
LDA #CMDREAD ; IDE READ MULTIPLE
STA CF_COMAND
BSR WAITRDY
*
* READ LOOP
*
CLRB
RDLP1 BSR WAITDRQ
LDA CF_DATA
STA ,X+
DECB
BNE RDLP1
*
CLRB
RDLP2 BSR WAITDRQ
LDA CF_DATA
DECB
BNE RDLP2
*
BSR WAITRDY
CLRB
RTS
*
* WAIT UNTIL READY
*
WAITRDY LDA CF_STATUS
BITA #BSY
BNE WAITRDY
LDA CF_STATUS
BITA #DRDY
BEQ WAITRDY
RTS
*
* WAIT FOR DATA REQUEST
*
WAITDRQ LDA CF_STATUS
BITA #DRQ
BEQ WAITDRQ
RTS
*
END
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