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MS-DOS/v2.0/source/SYSCALL.ASM

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MS-DOS v2.0 Release
1983-08-13 01:53:34 +01:00
;
; system call entry points MSDOS
;
INCLUDE DOSSEG.ASM
CODE SEGMENT BYTE PUBLIC 'CODE'
ASSUME SS:DOSGROUP,CS:DOSGROUP
.xlist
.xcref
INCLUDE DOSSYM.ASM
INCLUDE DEVSYM.ASM
.cref
.list
i_need YEAR,WORD
i_need DAY,BYTE
i_need WeekDay,BYTE
i_need TimeBuf,6
i_need BCLOCK,DWORD
i_need DskErr,BYTE
i_need Attrib,BYTE
i_need Name1,BYTE
i_need Name2,BYTE
i_need Name3,BYTE
i_need DelAll,BYTE
i_need ThisDPB,DWORD
i_need CurBuf,DWORD
i_need LastEnt,WORD
i_need ThisDrv,BYTE
i_need DirStart,WORD
i_need DevPt,DWORD
i_need Creating,BYTE
i_need VolID,BYTE
i_need FoundDel,BYTE
SUBTTL DATE AND TIME - SYSTEM CALLS 42,43,44,45; S/G DATE,TIME
PAGE
procedure $GET_DATE,NEAR ;System call 42
ASSUME DS:NOTHING,ES:NOTHING
; Inputs:
; None
; Function:
; Return current date
; Returns:
; Date in CX:DX
PUSH SS
POP DS
ASSUME DS:DOSGROUP
invoke READTIME ;Check for rollover to next day
MOV AX,[YEAR]
MOV BX,WORD PTR [DAY]
invoke get_user_stack ;Get pointer to user registers
ASSUME DS:NOTHING
MOV [SI.user_DX],BX ;DH=month, DL=day
ADD AX,1980 ;Put bias back
MOV [SI.user_CX],AX ;CX=year
MOV AL,BYTE PTR [WEEKDAY]
RET
$GET_DATE ENDP
procedure $SET_DATE,NEAR ;System call 43
ASSUME DS:NOTHING,ES:NOTHING
; Inputs:
; CX:DX valid date
; Function:
; Set current date
; Returns:
; AL = -1 date bad, = 0 OK
MOV AL,-1 ;Be ready to flag error
SUB CX,1980 ;Fix bias in year
JC RET24 ;Error if not big enough
CMP CX,119 ;Year must be less than 2100
JA RET24
OR DH,DH
JZ RET24
OR DL,DL
JZ RET24 ;Error if either month or day is 0
CMP DH,12 ;Check against max. month
JA RET24
PUSH SS
POP DS
ASSUME DS:DOSGROUP
invoke DODATE
RET24: RET
$SET_DATE ENDP
procedure $GET_TIME,NEAR ;System call 44
ASSUME DS:NOTHING,ES:NOTHING
; Inputs:
; None
; Function:
; Get current time
; Returns:
; Time in CX:DX
PUSH SS
POP DS
ASSUME DS:DOSGROUP
invoke READTIME
invoke get_user_stack ;Get pointer to user registers
MOV [SI.user_DX],DX
MOV [SI.user_CX],CX
XOR AL,AL
RET26: RET
$GET_TIME ENDP
procedure $SET_TIME,NEAR ;System call 45
;Time is in CX:DX in hours, minutes, seconds, 1/100 sec.
ASSUME DS:NOTHING,ES:NOTHING
; Inputs:
; CX:DX = Time
; Function:
; Set time
; Returns:
; AL = -1 time bad, = 0 OK
MOV AL,-1 ;Flag in case of error
CMP CH,24 ;Check hours
JAE RET26
CMP CL,60 ;Check minutes
JAE RET26
CMP DH,60 ;Check seconds
JAE RET26
CMP DL,100 ;Check 1/100's
JAE RET26
PUSH CX
PUSH DX
PUSH SS
POP DS
ASSUME DS:DOSGROUP
MOV BX,OFFSET DOSGROUP:TIMEBUF
MOV CX,6
XOR DX,DX
MOV AX,DX
PUSH BX
invoke SETREAD
ASSUME ES:DOSGROUP
PUSH DS
LDS SI,[BCLOCK]
ASSUME DS:NOTHING
invoke DEVIOCALL2 ;Get correct day count
POP DS
ASSUME DS:DOSGROUP
POP BX
invoke SETWRITE
POP WORD PTR [TIMEBUF+4]
POP WORD PTR [TIMEBUF+2]
LDS SI,[BCLOCK]
ASSUME DS:NOTHING
invoke DEVIOCALL2 ;Set the time
XOR AL,AL
RET
$SET_TIME ENDP
SUBTTL DISK R/W ROUTINES
PAGE
procedure $FCB_SEQ_READ,NEAR ; System call 20
ASSUME DS:NOTHING,ES:NOTHING
; Inputs:
; DS:DX Points to openned FCB
; Function:
; Read next record from file to disk transfer address
; Returns:
; AL = 1 EOF record is empty
; AL = 3 EOF record is partial zero filled
; AL = 2 No room at disk transfer address
; AL = 0 All OK
invoke GETREC
invoke LOAD
JMP SHORT FINSEQ
entry $FCB_SEQ_WRITE ; System call 21
ASSUME DS:NOTHING,ES:NOTHING
; Inputs:
; DS:DX Points to openned FCB
; Function:
; Write next record to file from disk transfer address
; Returns:
; AL = 1 Disk full
; AL = 2 No room in disk transfer segment
; AL = 0 All OK
invoke GETREC
invoke STORE
FINSEQ:
JCXZ SETNREX
ADD AX,1
ADC DX,0
JMP SHORT SETNREX
entry $FCB_RANDOM_READ ; System call 33
ASSUME DS:NOTHING,ES:NOTHING
; Inputs:
; DS:DX Points to openned FCB
; Function:
; Read record addressed by random record field from file to
; disk transfer address
; Returns:
; AL = 1 EOF record is empty
; AL = 3 EOF record is partial zero filled
; AL = 2 No room at disk transfer address
; AL = 0 All OK
invoke GETRRPOS1
invoke LOAD
JMP SHORT FINRND
entry $FCB_RANDOM_WRITE ; System call 34
ASSUME DS:NOTHING,ES:NOTHING
; Inputs:
; DS:DX Points to openned FCB
; Function:
; Write record addressed by random record field to file from
; disk transfer address
; Returns:
; AL = 1 Disk full
; AL = 2 No room in disk transfer segment
; AL = 0 All OK
invoke GETRRPOS1
invoke STORE
JMP SHORT FINRND
entry $FCB_RANDOM_READ_BLOCK ; System call 39
ASSUME DS:NOTHING,ES:NOTHING
; Inputs:
; DS:DX Points to openned FCB
; CX = Record count
; Function:
; Read CX records starting at random record field from file
; to disk transfer address
; Returns:
; AL = 1 EOF record is empty
; AL = 3 EOF record is partial zero filled
; AL = 2 No room at disk transfer address
; AL = 0 All OK
; CX = Actual number of records read
invoke GETRRPOS
invoke LOAD
JMP SHORT FINBLK
entry $FCB_RANDOM_WRITE_BLOCK ; System call 40
ASSUME DS:NOTHING,ES:NOTHING
; Inputs:
; DS:DX Points to openned FCB
; CX = Record count
; Function:
; Write CX records starting at random record field to file
; from disk transfer address
; If CX = 0 File is set to length determined from random record field
; Returns:
; AL = 1 Disk full
; AL = 2 No room in disk transfer segment
; AL = 0 All OK
; CX = Actual number of records written
invoke GETRRPOS
invoke STORE
FINBLK:
invoke get_user_stack
MOV [SI.user_CX],CX
entry FINNOSAV
JCXZ FINRND
ADD AX,1
ADC DX,0
FINRND:
MOV WORD PTR ES:[DI.fcb_RR],AX
MOV ES:[DI.fcb_RR+2],DL
OR DH,DH
JZ SETNREX
MOV ES:[DI.fcb_RR+3],DH ; Save 4 byte of RECPOS only if significant
SETNREX:
MOV CX,AX
AND AL,7FH
MOV ES:[DI.fcb_NR],AL
AND CL,80H
SHL CX,1
RCL DX,1
MOV AL,CH
MOV AH,DL
MOV ES:[DI.fcb_EXTENT],AX
MOV AL,BYTE PTR [DSKERR]
RET4:
RET
$FCB_SEQ_READ ENDP
SUBTTL $FCB_DELETE -- SYSTEM CALL 19
PAGE
procedure $FCB_DELETE,NEAR ; System call 19
ASSUME DS:NOTHING,ES:NOTHING
; Inputs:
; DS:DX point to unopened FCB
; Function:
; Delete all matching entries
; Returns:
; AL = -1 if no entries matched, otherwise 0
invoke MOVNAME
ASSUME ES:DOSGROUP
MOV AL,-1
MOV BYTE PTR [FoundDel],AL
JC RET4
MOV AL,BYTE PTR [ATTRIB]
AND AL,attr_hidden+attr_system+attr_directory+attr_volume_id+attr_read_only
; Look only at hidden bits
CMP AL,attr_hidden+attr_system+attr_directory+attr_volume_id+attr_read_only
; All must be set
JNZ NOTALL
MOV CX,11
MOV AL,"?"
MOV DI,OFFSET DOSGROUP:NAME1
REPE SCASB ; See if name is *.*
JNZ NOTALL
MOV BYTE PTR [DELALL],0 ; DEL *.* - flag deleting all
NOTALL:
invoke FINDNAME
ASSUME DS:DOSGROUP
MOV AL,-1
JC RET4
OR AH,AH ; Check if device name
JS RET4 ; Can't delete I/O devices
DELFILE:
LES BP,[THISDPB]
MOV AH,BYTE PTR [DELALL]
PUSH DS
LDS DI,[CURBUF]
ASSUME DS:NOTHING
TEST [Attrib],attr_read_only ; are we deleting RO files too?
JNZ DoDelete ; yes
TEST DS:[BX.dir_attr],attr_read_only
JZ DoDelete ; not read only
POP DS
JMP SHORT DelNxt
DoDelete:
MOV BYTE PTR [FoundDel],0
MOV [DI.BUFDIRTY],1
MOV BYTE PTR [BX],AH
MOV BX,[SI]
POP DS
ASSUME DS:DOSGROUP
OR BX,BX
JZ DELNXT
CMP BX,ES:[BP.dpb_max_cluster]
JA DELNXT
invoke RELEASE
DELNXT:
invoke GETENTRY ; Registers need to be reset
invoke NEXTENT
JNC DELFILE
CALL FLUSHRET1
MOV AL,BYTE PTR [FoundDel]
RET
$FCB_DELETE ENDP
SUBTTL $FCB_RENAME -- SYSTEM CALL 23; RENAME FILES
PAGE
ERRETJ: JMP ERRET
procedure $FCB_RENAME,NEAR ; System call 23
ASSUME DS:NOTHING,ES:NOTHING
; Inputs:
; DS:DX point to a modified FCB (DS:DX+11H points to destination
; name)
; Function:
; Rename all matching entries to indicated name
; Returns:
; AL = -1 if no entries matched, otherwise 0
invoke MOVNAME
ASSUME ES:DOSGROUP
JC ERRETJ
ADD SI,5
MOV DI,OFFSET DOSGROUP:NAME2
invoke LODNAME
JC ERRETJ ; Report error if second name invalid
invoke FINDNAME
ASSUME DS:DOSGROUP
JC ERRETJ
OR AH,AH ; Check if I/O device name
JS ERRETJ ; If so, can't rename it
MOV SI,OFFSET DOSGROUP:NAME1
MOV DI,OFFSET DOSGROUP:NAME3
MOV CX,13
REP MOVSB ; Copy name to search for --include attribute byte
RENFIL:
MOV DI,OFFSET DOSGROUP:NAME1
MOV SI,OFFSET DOSGROUP:NAME2
MOV CX,11
NEWNAM:
LODSB
CMP AL,"?"
JNZ NOCHG
PUSH DS
MOV DS,WORD PTR [CURBUF+2]
MOV AL,[BX]
POP DS
NOCHG:
STOSB
INC BX
LOOP NEWNAM
INC DI
MOV BYTE PTR [DI],attr_all ;Sets ATTRIB
; Stop duplicates with any attributes
invoke DEVNAME ; Check if giving it a device name
JNC RENERR
XOR AX,AX
PUSH [LASTENT]
invoke FINDENTRY ; See if new name already exists
POP AX
JNC RENERR ; Error if found
LES BP,[THISDPB]
invoke GETENT ; Re-read matching entry
MOV DI,BX ; Leave BX,DX until call to NEXTENT
MOV ES,WORD PTR [CURBUF+2]
MOV SI,OFFSET DOSGROUP:NAME1
MOV CX,11
REP MOVSB ; Replace old name with new one
MOV DI,WORD PTR [CURBUF]
MOV ES:[DI.BUFDIRTY],1 ; Directory changed
PUSH SS
POP ES
MOV SI,OFFSET DOSGROUP:NAME3
MOV DI,OFFSET DOSGROUP:NAME1
MOV CX,13 ; Include attribute byte
REP MOVSB ; Copy name back into search buffer
invoke NEXTENT
JNC RENFIL
JMP FLUSHRET1
RENERR:
CALL FLUSHRET1
ERRET:
MOV AL,-1
RET
$FCB_RENAME ENDP
SUBTTL $FCB_OPEN -- SYSTEM CALL 15; OPEN A FILE
PAGE
procedure $FCB_OPEN,NEAR ; System call 15
ASSUME DS:NOTHING,ES:NOTHING
; Inputs:
; DS:DX point to an unopened FCB
; Function:
; Open indicated file and fill in FCB
; Returns:
; AL = -1 if no entries matched, otherwise 0
; FOR INTERNAL USE
; [CURBUF+2]:SI and [CURBUF+2]:BX Preserved
invoke GETFILE
ASSUME DS:DOSGROUP,ES:NOTHING
entry DOOPEN
; Enter here to perform $FCB_OPEN on file already found
; in directory. AH=device ID number, DS=CS, BX points to directory
; entry in [CURBUF], SI points to First Cluster field, and
; ES:DI point to the FCB to be opened. This entry point
; is used by $FCB_CREATE.
JC ERRET
PUSH SI
PUSH AX ; Save I/O driver number
XOR AL,AL
OR AH,AH
JS OPENDEV
MOV AL,[THISDRV]
MOV DS,WORD PTR [CURBUF+2]
ASSUME DS:NOTHING
INC AX
OPENDEV:
STOSB
XOR AX,AX
IF ZEROEXT
ADD DI,11
STOSW ; Zero low byte of extent field if ZERPEXT only
ELSE
ADD DI,12 ; Point to high half of CURRENT BLOCK field
STOSB ; Set it to zero (CP/M programs set low byte)
ENDIF
MOV AL,128 ; Default record size
STOSW ; Set record size
LODSW ; Get starting cluster
MOV DX,AX ; Save it for the moment
MOVSW ; Transfer size to FCB
MOVSW
MOV AX,[SI-8] ; Get date
STOSW ; Save date in FCB
MOV AX,[SI-10] ; Get time
STOSW ; Save it in FCB
POP AX ; Restore I/O driver number
POP SI
MOV AL,AH
OR AL,40H ; Not dirty
STOSB
JS SAVDEVPT ; If device, go save pointer to it
MOV AX,DX ; Restore starting cluster
STOSW ; first cluster
PUSH AX ; save cluster
XOR AX,AX
STOSW ; clus pos
POP AX ; last cluster
STOSB
MOV AL,AH
MOV AH,BYTE PTR [DIRSTART]
PUSH CX
MOV CL,4
SHL AH,CL
OR AL,AH
STOSB
MOV AX,[DIRSTART]
MOV CL,4
SHL AX,CL
POP CX
MOV AL,AH
STOSB
OPEN_RET:
XOR AX,AX
RET
SAVDEVPT:
ASSUME DS:DOSGROUP
LDS AX,[DEVPT]
ASSUME DS:NOTHING
STOSW
MOV ES:[DI],DS
JMP SHORT OPEN_RET
$FCB_OPEN ENDP
SUBTTL $FCB_CLOSE -- SYSTEM CALL 16; CLOSE FILE
PAGE
procedure $FCB_CLOSE,NEAR ; System call 16
ASSUME DS:NOTHING,ES:NOTHING
; Inputs:
; DS:DX point to an opened FCB
; Function:
; Close the indicated file
; Returns:
; AL = -1 if disk has been changed, otherwise 0
MOV DI,DX
CMP BYTE PTR [DI],-1 ; Check for extended FCB
JNZ NORMFCB3
ADD DI,7
NORMFCB3:
TEST [DI.fcb_DEVID],devid_file_clean+devid_device
; Allow only dirty files
JNZ OKRET1 ; can't close I/O device or not written
invoke MOVNAMENOSET
JC BADCLOSE ; Bad file name
entry FCB_CLOSE_INNER
PUSH DX
PUSH DS
MOV SI,DX
MOV BX,[SI.fcb_LSTCLUS+1]
MOV CL,4
SHR BX,CL
PUSH BX
PUSH SS
POP DS
ASSUME DS:DOSGROUP
invoke FATREAD
POP BX
invoke SETDIRSRCH
invoke FINDENTRY
POP ES
POP DI
JC BADCLOSE
LDS BX,[CURBUF]
ASSUME DS:NOTHING
; note that SI points to dir_first...
OR BYTE PTR [SI-dir_first+dir_attr],attr_archive
MOV CX,ES:[DI.fcb_FIRCLUS]
MOV [SI-dir_first+dir_first],CX
MOV DX,ES:WORD PTR [DI.fcb_FILSIZ]
MOV [SI-dir_first+dir_size_l],DX
MOV DX,ES:WORD PTR [DI.fcb_FILSIZ+2]
MOV [SI-dir_first+dir_size_h],DX
MOV DX,ES:[DI.fcb_FDATE]
MOV [SI-dir_first+dir_date],DX
MOV DX,ES:[DI.fcb_FTIME]
MOV [SI-dir_first+dir_time],DX
MOV [BX.BUFDIRTY],1
PUSH SS
POP DS
ASSUME DS:DOSGROUP
FLUSHRET1:
LES BP,[THISDPB]
MOV AL,ES:[BP.dpb_drive]
invoke FLUSHBUF
OKRET1:
XOR AL,AL
RET
BADCLOSE:
MOV AL,-1
RET
$FCB_CLOSE ENDP
SUBTTL $FCB_CREATE -- SYSTEM CALL 22; MAKE AND OPEN A NEW FILE
PAGE
procedure $FCB_CREATE,NEAR ; System call 22
ASSUME DS:NOTHING,ES:NOTHING
; Inputs:
; DS:DX point to an unopened FCB
; Function:
; If file does not exist, create it and open it
; If file exists, free up its contents and open the file
; Returns:
; AL = -1 if file cannot be created, otherwise 0
invoke MOVNAME
ASSUME ES:DOSGROUP
JC ERRET3
MOV DI,OFFSET DOSGROUP:NAME1
MOV CX,11
MOV AL,"?"
REPNE SCASB
JZ ERRET3
MOV BYTE PTR [CREATING],-1
PUSH DX
PUSH DS
invoke FINDNAME
ASSUME DS:DOSGROUP
NWENTY:
LES BP,[THISDPB]
ASSUME ES:NOTHING
JNC EXISTENT
invoke BUILDDIR
JC ERRPOP
invoke GETENT ; Point at that free entry
JMP SHORT FREESPOT
ERRPOP:
POP DS
POP DX
ASSUME DS:NOTHING
ERRET3:
JMP SHORT BADCLOSE
entry NEWENTRY
POP DX ; Return address
POP ES ; ES
POP CX ; DI
PUSH DX
PUSH CX
PUSH ES
JMP NWENTY
EXISTENT:
ASSUME DS:DOSGROUP
JNZ ERRPOP ; Error if attributes don't match
OR AH,AH ; Check if file is I/O device
JS OPENJMP ; If so, no action
PUSH DS
LDS DI,[CURBUF]
ASSUME DS:NOTHING
MOV CX,[SI] ; Get pointer to clusters
MOV SI,[DI.BUFSECNO]
POP DS
ASSUME DS:DOSGROUP
JCXZ FREESPOT
CMP CX,ES:[BP.dpb_max_cluster]
JA FREESPOT
SUB BX,DI
PUSH BX
PUSH SI ; Save sector number
MOV BX,CX
invoke RELEASE ; Free any data already allocated
POP DX
XOR AL,AL
invoke GETBUFFR
POP BX
ADD BX,WORD PTR [CURBUF]
FREESPOT:
TEST BYTE PTR [ATTRIB],attr_volume_id
JZ NOTVOLID
CMP BYTE PTR [VOLID],0
JNZ ERRPOP ; Can't create a second volume ID
NOTVOLID:
MOV ES,WORD PTR [CURBUF+2]
MOV DI,BX
MOV SI,OFFSET DOSGROUP:NAME1
MOV CX,5
MOVSB
REP MOVSW
MOV AL,[ATTRIB]
STOSB
MOV CL,5
XOR AX,AX
REP STOSW
invoke DATE16
XCHG AX,DX
STOSW
XCHG AX,DX
STOSW
XOR AX,AX
PUSH DI
STOSW
STOSW
STOSW
MOV SI,WORD PTR [CURBUF]
MOV ES:[SI.BUFDIRTY],1
LES BP,[THISDPB]
MOV AL,ES:[BP.dpb_drive]
PUSH AX
PUSH BX
invoke FLUSHBUF
POP BX
POP AX
POP SI
MOV AH,AL ; Get I/O driver number back
OPENJMP:
CLC ; Clear carry so OPEN won't fail
POP ES
POP DI
ASSUME ES:NOTHING
JMP DOOPEN
$FCB_CREATE ENDP
do_ext
CODE ENDS
END