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TITLE MSAUX - DOS 3.3
;----------------------------------------------------------------
; :
; A U X - AUXILARY DEVICE DRIVER :
; :
; :
; This file contains the Auxilary Device Driver. The :
; auxilary driver handles calls to and from the RS-232 port. :
; Three devices uses this code: AUX, COM1, and COM2. AUX and :
; COM1 talk to the zero RS-232 card and COM2 talks to the :
; 'one' RS-232 card. The beginning of the interrupt entry :
; point for these devices sets the variable AUXNUM in the :
; msbio.asm module. If the value is 0 the routines in this :
; file will talk to the the 'zero' card. If the value in :
; AUXNUM is 1 the routines will talk to the 'one' card. :
; The procedure GETDX is called to put the value 0 or 1 in :
; the DX register depending on the value in AUXBUF. :
; :
; The routines in this files are: :
; :
; routine function :
; ------- -------- :
; AUX$READ Read characters from the :
; specified device. :
; AUX$RDND Non-desrucrtive read with :
; no waiting. :
; AUX$FLSH Flush specified device input :
; buffer. :
; AUX$WRIT Write characters to the :
; specified device. :
; AUX$WRST Get status of specified :
; device :
; :
; These routines are not called directly. Call are made via :
; the strategy and interrupt entry point (see Device Header). :
; :
; Data structure: :
; The Aux Device has a two byte buffer called AUXBUF. The :
; first byte is for the zero card, the second byte is for the :
; one card. A zero value in the byte indicates the buffer is :
; empty. The routines use GETBX to get the address of the :
; buffer. :
; :
;----------------------------------------------------------------
;;Ver 3.30 modification ---------------------------
itest=0
INCLUDE MSGROUP.INC ;DEFINE CODE SEGMENT
INCLUDE JUMPMAC.INC
INCLUDE MSMACRO.INC
EXTRN ERR$CNT:NEAR ;MSBIO1
EXTRN GETDX:NEAR ;MSBIO1
EXTRN RDEXIT:NEAR ;MSCON
EXTRN EXIT:NEAR ;MSBIO1
EXTRN BUS$EXIT:NEAR ;MSBIO1
;DATA
EXTRN AUXBUF:BYTE ;MSDATA
; VALUES IN AH, REQUESTING FUNCTION OF INT 14H IN ROM BIOS
AUXFUNC_SEND EQU 1 ;TRANSMIT
AUXFUNC_RECEIVE EQU 2 ;READ
AUXFUNC_STATUS EQU 3 ;REQUEST STATUS
; ERROR FLAGS, REPORTED BY INT 14H
; THESE FLAGS REPORTED IN AH:
FLAG_DATA_READY EQU 01H ;DATA READY
FLAG_OVERRUN EQU 02H ;OVERRUN ERROR
FLAG_PARITY EQU 04H ;PARITY ERROR
FLAG_FRAME EQU 08H ;FRAMING ERROR
FLAG_BREAK EQU 10H ;BREAK DETECT
FLAG_TRANHOL_EMP EQU 20H ;TRANSMIT HOLDING REGISTER EMPTY
FLAG_TRANSHF_EMP EQU 40H ;TRANSMIT SHIFT REGISTER EMPTY
FLAG_TIMEOUT EQU 80H ;TIMEOUT
; THESE FLAGS REPORTED IN AL:
FLAG_DELTA_CTS EQU 01H ;DELTA CLEAR TO SEND
FLAG_DELTA_DSR EQU 02H ;DELTA DATA SET READY
FLAG_TRAIL_RING EQU 04H ;TRAILING EDGE RING INDICATOR
FLAG_DELTA_SIG EQU 08H ;DELTA RECEIVE LINE SIGNAL DETECT
FLAG_CTS EQU 10H ;CLEAR TO SEND
FLAG_DSR EQU 20H ;DATA SET READY
FLAG_RING EQU 40H ;RING INDICATOR
FLAG_REC_SIG EQU 80H ;RECEIVE LINE SIGNAL DETECT
;;End of modification ------------------
;----------------------------------------------------------------
; :
; Read zero or more characters from Auxilary Device :
; :
; input:es:[di] points to area to receive aux data :
; cx has number of bytes to be read :
; "auxnum" first byte has number of aux device (rel 0):
; :
;----------------------------------------------------------------
PUBLIC AUX$READ
AUX$READ PROC NEAR
ASSUME DS:CODE ; SET BY AUX DEVICE DRIVER ENTRY ROUTINE
jcxz EXVEC2 ; if no characters, get out
call GETBX ; put address of AUXBUF in BX
xor AX,AX ; clear AX register
xchg AL,[BX] ; Get character , if any, from
; buffer and clear buffer
or AL,AL ; if AL is nonzero there was a
; character in the buffer
jnz AUX2 ; if so skip AUXIN call
AUX1: ;
call AUXIN ; get character from port
AUX2: ;
stosb ; store character
loop AUX1 ; if more character, go around again
EXVEC2: ;
Jump EXIT ; all done, successful exit
AUX$READ ENDP
;
; AUXIN: make a call on ROM BIOS to read character from
; the auxilary device, then do some error checking.
; If an error occurs then AUXIN jumps to ERR$CNT and
; does NOT return to where it was called from.
;
AUXIN PROC NEAR
mov ah,AUXFUNC_RECEIVE
call AUXOP
;check for Frame, Parity, or Overrun errors
;WARNING: these error bits are unpredictable
; if timeout (bit 7) is set
test ah,FLAG_FRAME or FLAG_PARITY or FLAG_OVERRUN
jz AROK ;No error if all bits are clear
;Error getting character
add sp,+2 ;Remove rtn address (near call)
xor al,al
or al,FLAG_REC_SIG or FLAG_DSR or FLAG_CTS
JUMP ERR$CNT
AROK:
RET ;CHAR JUST READ IS IN AL, STATUS IS IN AH
AUXIN ENDP
;----------------------------------------------------------------
; :
; Aux non-destructive read with no waiting :
; :
; input: es:[di] points to area to receive aux data :
; :
;----------------------------------------------------------------
;
PUBLIC AUX$RDND
AUX$RDND PROC NEAR
ASSUME DS:CODE ; SET BY AUX DEVICE DRIVER ENTRY ROUTINE
call GETBX ; have BX point to AUXBUF
mov AL,[BX] ; copy contents of buffer to AL
or AL,AL ; if AL is non-zero (char in buffer)
jnz AUXRDX ; then return character
call AUXSTAT ; if not, get status of AUX device
TEST AH,FLAG_DATA_READY ;TEST DATA READY
jz AUXBUS ; then device is busy (not ready)
TEST AL,FLAG_DSR ;TEST DATA SET READY
jz AUXBUS ; then device is busy (not ready)
call AUXIN ; else aux is ready, get character
call GETBX ; have bx point to AUXBUF
mov [BX],AL ; save character in buffer
AUXRDX: ;
Jump RDEXIT ; return character
AUXBUS: ;
Jump BUS$EXIT ; jump to device busy exit
AUX$RDND ENDP
;----------------------------------------------------------------
; :
; Aux Output Status :
; :
;----------------------------------------------------------------
PUBLIC AUX$WRST
AUX$WRST PROC NEAR
ASSUME DS:CODE ; SET BY AUX DEVICE DRIVER ENTRY ROUTINE
call AUXSTAT ; get status of AUX in AX
; now test to see if device is busy
; if this bit is not set,
;;Ver 3.30 modification -----------------------
TEST AL,FLAG_DSR ;TEST DATA SET READY
jz AUXBUS ; then device is busy (not ready)
TEST AH,FLAG_TRANHOL_EMP ;TEST TRANSMIT HOLD REG EMPTY
;;End of modification -------------------------
jz AUXBUS ; then device is busy (not ready)
Jump Exit
AUX$WRST ENDP
;
; AUXSTAT makes a call on the ROM-BIOS to determine the status
; of the auxilary device
; Outputs:
; AX is filled with status of port.
; DX is changes to specify which card - either 0, 1 (, 2, 3) ;ba
; NO other registers are modified
;
AUXSTAT proc near
mov ah,AUXFUNC_STATUS
call AUXOP
ret
AUXSTAT endp
AUXOP PROC NEAR
;AH=FUNCTION CODE
;0=INIT, 1=SEND, 2=RECEIVE, 3=STATUS
call GETDX ; have DX point to proper card
int 14h ; call rom-bios for status
ret
AUXOP ENDP
;----------------------------------------------------------------
; :
; Flush AUX Input buffer - set contents of AUXBUF to zero :
; :
;----------------------------------------------------------------
PUBLIC AUX$FLSH
AUX$FLSH PROC NEAR
ASSUME DS:CODE ; SET BY AUX DEVICE DRIVER ENTRY ROUTINE
call GETBX ; get BX to point to AUXBUF
mov BYTE PTR [BX],0 ; zero out buffer
Jump Exit ; all done, successful return
AUX$FLSH ENDP
;----------------------------------------------------------------
; :
; Write to Auxilary Device :
; :
;----------------------------------------------------------------
PUBLIC AUX$WRIT
AUX$WRIT PROC NEAR
ASSUME DS:CODE ; SET BY AUX DEVICE DRIVER ENTRY ROUTINE
jcxz EXVEC2 ; if CX is zero, no characters
; to be written, jump to exit
AUX$LOOP:
mov AL,ES:[DI] ; get character to be written
inc DI ; move DI pointer to next character
;;Ver 3.30 modification ---------------------------
MOV AH,AUXFUNC_SEND ;VALUE=1, INDICATES A WRITE
CALL AUXOP ;SEND CHARACTER OVER AUX PORT
TEST AH,FLAG_TIMEOUT ;CHECK FOR ERROR
;;End of modification ---------------------------
jz AWOK ; then no error
mov AL,10 ; else indicate write fault
Jump ERR$CNT ; call error routines
; if CX is non-zero, still more
AWOK:
loop AUX$LOOP ; more characrter to print
Jump Exit ; all done, successful return
AUX$WRIT ENDP
;
; GETBX puts the address of AUXBUF (the Auxilary Device buffer)
; in BX. After calling GETBX, a routine can get to AUXBUF
; with [BX].
;
; NOTE: The getdx routine is in msbio1 and looks like:
; mov dx,word ptr cs:[auxnum]
;
GETBX PROC NEAR
call GETDX
mov BX,DX
add BX,OFFSET AUXBUF
ret
GETBX ENDP
CODE ENDS
END
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