Alex van der Wal, 15-08-93
; BDOS fileshell routines for secure file loading and saving
; Version for: Sunrise Magazine Special 4
; File: EASYBDOS.ASC V2.00
; By: Alex van der Wal Last update: 15-8-93
; Alias: Savage '93 (Fuzzy Logic) !! It ain't much if it ain't Dutch !!
;
; Note:
; - The BIOS (PAGE 0) must be active for error handling and text output
; (Stupid) example of fileshell load function
; ORG &HD000
; LD A,(&HF342) ; Slot & Subslot of main RAM
; CALL FINSTL ; Install the fileshell
; JR C,EIND
; LD HL,DATA ; HL points to address of filename string
; CALL FOPEN ; Open file
; JR C,EIND
;LUS: LD HL,&H8000 ; Startaddress for data to load
; LD DE,&H4000 ; Blocklength
; CALL FBLKRD ; Read file block
; JR C,EIND
; CP "r"
; JR NZ,LUS
;EIND: CALL FRESET ; Reset the fileshell
; RET
;
;DATA: DM "MMU2info","TXT"
ENASLT: EQU &H24
PRINTC: EQU &HA2
BDOS: EQU &HF37D
F##ERR: EQU &HF323 ; Double pointer address to error routine
BLOAD: EQU &HFE ; ID byte van een BLOAD type file
VDPBF1: EQU &HF3DF
VDPBF2: EQU &HFFE7-8
ORG &HC000
; Print string
PRINTS: LD A,(HL)
INC HL
AND A
RET Z
CALL PRINTC
JR PRINTS
; Print string with fixed length
PRINTF: LD A,(HL)
INC HL
CALL PRINTC
DJNZ PRINTF
RET
; Wait until SPACE is pressed
WAITSP: CALL &H9F
CP " "
JR NZ,WAITSP
RET
; Print filename. In: HL with filename address
PRFLNM: PUSH BC
LD B,8
CALL PRINTF
LD A,"."
CALL PRINTC
LD B,3
CALL PRINTF
LD A," "
CALL PRINTC
POP BC
RET
; Install BDOS fileshell
; In : A (See BIOS rout 24H)
; A must contain the settings for PAGE 1 (SLOT/SUBSLOT)
; Out: Cy, on error
FINSTL: LD (PG1SET),A
LD A,(FSTAT)
BIT 0,A
LD C,0
JP NZ,FERROR
SET 0,A
LD (FSTAT),A ; Fileshell install executed
LD A,255
LD (CURDRV),A
LD HL,0
LD (FLELEN),HL
LD HL,(BDOS+1)
LD (OLDDOS+1),HL
LD HL,FBDOS
LD (BDOS+1),HL
LD HL,(F##ERR) ; Double pointer to error routine
LD (_##ERR),HL
LD HL,DSERPT ; Pointer address to error routine
LD (F##ERR),HL
XOR A
RET
; Reset BDOS fileshell
; Out: Cy, on error
FRESET: LD A,(FSTAT)
BIT 0,A
LD C,1
JP Z,FERROR
RES 0,A
LD (FSTAT),A
BIT 2,A ; Writing to disc ?
CALL NZ,FCLOSE ; then close that file
LD HL,(OLDDOS+1)
LD (BDOS+1),HL
LD HL,(_##ERR)
LD (F##ERR),HL
XOR A
RET
; Open file
; In: HL, filename address
; Out: Cy, on error
FOPEN: LD A,(FSTAT)
CP &B00000001
LD C,2
JP NZ,FERROR
LD DE,FCB+1
LD BC,11
LDIR ; Copy filename to FCB
LD HL,FCB1
LD DE,FCB1+1
LD BC,25-1
LD (HL),B
LDIR
LD C,15
LD DE,FCB
CALL BDOS ; Open file
AND A
JR NZ,FOPN.0
LD HL,&H00
LD (FCB+&H0C),HL ; Current block
INC HL
LD (FCB+&H0E),HL ; Record length
LD HL,(FCB+&H10) ; File length
LD (FLELEN),HL ;
LD A,(FSTAT)
SET 1,A
LD (FSTAT),A
XOR A
RET
FOPN.0: LD HL,FCB+1
CALL PRFLNM
LD C,3
JP FERROR
; Load fileblock
; In: DE, blocklength
; HL, load address
; Out: Cy, on error
; Out: A , "r", Then file is 100% percent loaded
;
FBLKRD: LD A,(FSTAT)
CP &B00000011
LD C,2
JP NZ,FERROR
PUSH DE
EX DE,HL
LD C,26
CALL BDOS ; Set DMA address
POP DE
XOR A
LD HL,(FLELEN) ; # of Bytes still to load
SBC HL,DE
JR C,FBLR.1
LD (FLELEN),HL
LD A,H
OR L
JR NZ,FBLR.2
FBLR.1: ADD HL,DE
EX DE,HL
LD HL,0
LD (FLELEN),HL
LD A,(FSTAT) ; Loading ready after this read action
RES 1,A
LD (FSTAT),A
FBLR.2: EX DE,HL
CALL INTOFF
LD C,39
LD DE,FCB
CALL BDOS
CALL INTON
AND A
JR NZ,FBLR.3
LD A,(FSTAT)
BIT 1,A
RET NZ
LD A,"r" ; Mark succesfully loaded
RET
FBLR.3: LD HL,FCB+1
CALL PRFLNM
LD C,4
JP FERROR
; Create file
; In: HL, filename address
; Out: Cy : High, then an error occured
FCREAT: LD A,(FSTAT)
CP &B00000001
LD C,2
JP NZ,FERROR
LD DE,FCB+1
LD BC,11
LDIR ; Copy filename to FCB
LD HL,FCB1
LD DE,FCB1+1
LD BC,25-1
LD (HL),B
LDIR
LD HL,0
LD (FLELEN),A
LD C,22
LD DE,FCB
CALL BDOS
AND A
JR NZ,FCRE.0
LD HL,&H00
LD (FCB+&H0C),HL ; Current block
INC HL
LD (FCB+&H0E),HL ; Record length
LD A,(FSTAT)
SET 2,A
LD (FSTAT),A
XOR A
RET
FCRE.0: LD HL,FCB+1
CALL PRFLNM
LD C,5
JP FERROR
; Write fileblock
; In: DE, Blocklength
; HL, Startaddress
; Out: Cy, on error (File will be closed)
FBLKWR: LD A,(FSTAT)
CP &B00000101
LD C,2
JP NZ,FERROR
PUSH DE
EX DE,HL
LD C,&H1A
CALL BDOS
POP HL
LD DE,(FLELEN) ; Add length to FLELEN
EX DE,HL
ADD HL,DE
LD (FLELEN),HL
EX DE,HL
CALL INTOFF
LD DE,FCB
LD C,38
CALL BDOS
CALL INTON
AND A
RET Z
CALL FCLOSE
LD HL,FCB+1
CALL PRFLNM
LD C,6
JP FERROR
; Close file
FCLOSE: LD C,16
LD DE,FCB
CALL BDOS ; Close file
RET
; CHNDSK Waits for a diskchange, with conformation by the space key
; Request for same drive as current one is ignored !!
; In: A (0, then 'Insert source disk')
; (otherwise, 'Insert destination disk')
CHNDSK: LD B,A
LD A,(CURDRV)
CP 255
JR Z,CHND.2
CP B
RET Z
CHND.2: LD A,B
LD (CURDRV),A
LD HL,CHND.A
AND A
JR Z,CHND.1
LD HL,CHND.B
CHND.1: CALL PRINTS
; call beep
CALL WAITSP
RET
INTOFF: PUSH AF
LD A,(VDPBF1+1)
RES 5,A
INTO.0: LD (VDPBF1+1),A
DI
OUT (&H99),A
LD A,128+1
OUT (&H99),A
EI
POP AF
RET
INTON: PUSH AF
LD A,(VDPBF1+1)
SET 5,A
JR INTO.0
; BDOS call routine [system routine]
; In: BDOS parameters
; Out: BDOS parameters
FBDOS: PUSH BC
PUSH DE
PUSH HL
PUSH IX
PUSH IY
LD (SP_SAV),SP
CALL OLDDOS ; Call BDOS
FDOS.2: POP IY
POP IX
POP HL
POP DE
POP BC
RET
; BDOS error code [system routine]
; In: nothing
; Out: nothing
DSERPT: DW ERRCDE ; Pointer to error code
ERRCDE: LD HL,STDERR
CALL PRINTS
ERRC.0: CALL &H0156
CALL &H9F
SET 5,A ; Convert "R" to "r" for example
CP "r"
JR Z,ERRC.1
CP "a"
JR NZ,ERRC.0
LD HL,EOLN ; Abort
CALL PRINTS
LD A,(PG1SET)
LD H,&H40
CALL ENASLT
LD SP,(SP_SAV)
LD A,1 ; Signal BDOS error back
EI
JP FDOS.2
ERRC.1: LD HL,EOLN
CALL PRINTS
LD C,1 ; Retry
RET
; Print fileshell error
FERROR: LD HL,FERTXT
LD A,C
CALL PRTERR
SCF ; return Cy on error
RET
PRTERR: AND A
JR Z,PRTE.1
LD B,A
PRTE.0: LD A,(HL)
INC HL
AND A
JR NZ,PRTE.0
CP 255
JR Z,PRTE.2
DJNZ PRTE.0
PRTE.1: CALL PRINTS
LD HL,EOLN
CALL PRINTS
RET
PRTE.2: LD HL,FSYSER
CALL PRINTS
RET
; BDOS routine variables
CHND.A: DM "Insert source disk:",10,13,0
CHND.B: DM "Insert destination disk:",10,13,0
STDERR: DM 10,13,"Drive error !! Press 'r' to retry or 'a' to abort",10,13,0
FERTXT: DM "Fileshell already installed",0
DM "Fileshell not installed",0
DM "Status error",0
DM "not found",0
DM "has a read error",0
DM "cannot be created",0
DM "has a write error",0
FSYSER: DM "Unknown error [SYSTEM ERROR]",0
EOLN: DB 10,13,0
FSTAT: DB 0 ; Fileshell status
CURDRV: DB 255 ; Current drivenumber (255=invalid)
FLELEN: DW 0 ; Bytes to read / written bytes
_##ERR: DW 0 ; Double pointer to error code
OLDDOS: DB &HC3,0,0 ; Old BDOS call
PG1SET: DB 0 ; PAGE 1 memory settings
SP_SAV: DW 0 ; SP save address
; The following addresses must be located outside page 1 (4000H-7fffH) !
FCB: DEFM 0
DEFM "filename"
EXT: DEFM "ext"
FCB1: DEFS 25
END
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