ProfitPress Mega CDROM2 Shareware Freeware (MSDOS)(1992)(Eng)

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Assembly Source File | 1991-12-08 | 42.6 KB | 1,445 lines

TITLE COMM PAGE 75,132 ; Use AHD's handling of COM ports. Wm. W. Plummer, 11/29/91 ; Buffer sizes reduced and required to be 2**N. Wm. W. Plummer, 11/11/91 ; Accomodate V.24 requirements on DTR flaps. Wm. W. Plummer 10/15/91 ; Revised DTR_ON_COM to solve user problem. Wm. W. Plummer, 10/3/91 ; Make time delays independent of CPU speed. Wm. W. Plummer, 9/16/91 ; Use interrupts to trace CD, DSR, Wm. W. Plummer, 9/16/91 ; Remove modem control from TX_INT. Wm. W. Plummer, 9/13/91 ; Completely redo the XOFF/XON logic. Too many races before. Wm. W. Plummer ; Revise interrupt dispatch for speed & function. William W. Plummer, 9/12/91 ; Merge in ahd's changes to flush control Q,S when received as flow control ; SEND buffer allows one byte for a SENDII call. Avoids flow control ; lockups. - William W. Plummer, 8/30/91 ; Support for NS16550A chip with SILO - William W. Plummer, 8/30/91 ; Add modem_status() routine - William W. Plummer, 7/2/91 ; Put wrong code under AHD conditional - William W. Plummer, 7/2/91 ; Change TITLE, repair bad instr after INST3 - William W. Plummer, 7/1/91 ; Modified to use COM1 thru COM4 - William W. Plummer, 2/21/91 ; Eliminate (incomplete) support for DOS1 - William W. Plummer, 11/13/90 ; Changes may be copied and modified with no notice. Copyrights and copylefts ; are consider silly and do not apply. -- William W. Plummer ; modified to use MSC calling sequence. jrr 3/86 ;**************************************************************************** ; Communications Package for the IBM PC, XT, AT, PCjr and strict compatibles. ; May be copied and used freely -- This is a public domain program ; Developed by Richard Gillmann, John Romkey, Jerry Saltzer, ; Craig Milo Rogers, Dave Mitton and Larry Afrin. ; ; We'd sure like to see any improvements you might make. ; Please send all comments and queries about this package ; to GILLMANN@USC-ISIB.ARPA ; ; o Supports both serial ports simultaneously ; o All speeds to 19200 baud ; o Compatible with PC, XT, AT and PCjr. ; o Built in XON/XOFF flow control option ; o Assembly language calling conventions ; o Logs all comm errors ; o Direct connect or modem protocol PAGE ; ; ; MAXIMUM BUFFER SIZES -- *** MUST be powers of 2 **** R_SIZE EQU 1024 ; Recv buffer size S_SIZE EQU 256 ; Send buffer size ; INTERRUPT NUMBERS INT_COM1 EQU 0CH ; COM1: FROM 8259 INT_COM2 EQU 0BH ; COM2: FROM 8259 INT_COM3 EQU 0CH ; COM3: FROM 8259 INT_COM4 EQU 0BH ; COM4: FROM 8259 ; 8259 PORTS INTA00 EQU 20H ; 8259A PORT, A0 = 0 INTA01 EQU 21H ; 8259A PORT, A0 = 1 ; COM1: & COM3: LEVEL 4 IRQ4 EQU 2*2*2*2 ; 8259A OCW1 MASK, M4=1, A0=0 NIRQ4 EQU NOT IRQ4 AND 0FFH ; COMPLEMENT OF ABOVE EOI4 EQU 4 OR 01100000B ; 8259A OCW2 SPECIFIC IRQ4 EOI, A0=0 ; COM2: & COM4: LEVEL 3 IRQ3 EQU 2*2*2 ; 8259A OCW1 MASK, M3=1, A0=0 NIRQ3 EQU NOT IRQ3 AND 0FFH ; COMPLEMENT OF ABOVE EOI3 EQU 3 OR 01100000B ; 8259A OCW2 SPECIFIC IRQ3 EOI, A0=0 ; FLOW CONTROL CHARACTERS CONTROL_Q EQU 11H ; XON CONTROL_S EQU 13H ; XOFF ; MISC. DOS EQU 21H ; DOS FUNCTION CALLS PAGE ; ; ROM BIOS Data Area ; RBDA SEGMENT AT 40H RS232_BASE DW 4 DUP(?) ; ADDRESSES OF RS232 ADAPTERS RBDA ENDS ; ; ROM PC-Type IDENT ; ROM SEGMENT AT 0F000H ORG 0FFFEH ROMID DB ? ; 0FFH=PC OR EARLY XT, 0FEH=XT, 0FDH=JR ROM ENDS PAGE ; ; ; TABLE FOR EACH SERIAL PORT ; SP_TAB STRUC PORT DB ? ; 1 OR 2 OR 3 OR 4 ; PARAMETERS FOR THIS INTERRUPT LEVEL INT_COM DB ? ; INTERRUPT NUMBER IRQ DB ? ; 8259A OCW1 MASK NIRQ DB ? ; COMPLEMENT OF ABOVE EOI DB ? ; 8259A OCW2 SPECIFIC END OF INTERRUPT ; INTERRUPT HANDLERS FOR THIS LEVEL INT_HNDLR DW ? ; OFFSET TO INTERRUPT HANDLER OLD_COM_OFF DW ? ; OLD HANDLER'S OFFSET OLD_COM_SEG DW ? ; OLD HANDLER'S SEGMENT ; ATTRIBUTES INSTALLED DB ? ; IS PORT INSTALLED ON THIS PC? (1=YES,0=NO) BAUD_RATE DW ? ; 19200 MAX CONNECTION DB ? ; M(ODEM), D(IRECT) PARITY DB ? ; N(ONE), O(DD), E(VEN), S(PACE), M(ARK) STOP_BITS DB ? ; 1, 2 XON_XOFF DB ? ; E(NABLED), D(ISABLED) ; FLOW CONTROL STATE HOST_OFF DB ? ; HOST XOFF'ED (1=YES,0=NO) PC_OFF DB ? ; PC XOFF'ED (1=YES,0=NO) URGENT_SEND DB ? ; We MUST send one byte (XON/XOFF) SEND_OK DB ? ; DSR and CTS are ON ; ERROR COUNTS ERROR_BLOCK DW 8 DUP(?); EIGHT ERROR COUNTERS ; UART PORTS - DATREG thru MSR must be in order shown. DATREG DW ? ; DATA REGISTER IER DW ? ; INTERRUPT ENABLE REGISTER IIR DW ? ; INTERRUPT IDENTIFICATION REGISTER (RO) LCR DW ? ; LINE CONTROL REGISTER MCR DW ? ; MODEM CONTROL REGISTER LSR DW ? ; LINE STATUS REGISTER MSR DW ? ; MODEM STATUS REGISTER FCR EQU IIR ; FIFO Control Register (WO) ; Bits in FCR for NS16550A UART. Note that writes to FCR are ignored ; by other chips. FIFO_ENABLE EQU 001H ; Enable FIFO mode FIFO_CLR_RCV EQU 002H ; Clear receive FIFO FIFO_CLR_XMT EQU 004H ; Clear transmit FIFO FIFO_STR_DMA EQU 008H ; Start DMA Mode ; 10H and 20H bits are register bank select on some UARTs (not handled) FIFO_SZ_4 EQU 040H ; Warning level is 4 before end FIFO_SZ_8 EQU 080H ; Warning level is 8 before end FIFO_SZ_14 EQU 0C0H ; Warning level is 14 before end FIFO_SZ_MASK EQU 0C0H ; Size mask ; ; Commands used in code to operate FIFO. Made up as combinations of above ; FIFO_CLEAR EQU 0 ; Turn off FIFO FIFO_SETUP EQU FIFO_SZ_14 OR FIFO_ENABLE FIFO_INIT EQU FIFO_SETUP OR FIFO_CLR_RCV OR FIFO_CLR_XMT ; ; Miscellaneous FIFO-related stuff ; FIFO_ENABLED EQU 0C0H ; 16550 makes these equal FIFO_ENABLE FIFO_LEN EQU 16 ; Length of the FIFOs in a 16550A UART_SILO_LEN DB ? ; Size of a silo chunk (1 for 8250) ; ; BUFFER POINTERS START_TDATA DW ? ; INDEX TO FIRST CHARACTER IN X-MIT BUFFER END_TDATA DW ? ; INDEX TO FIRST FREE SPACE IN X-MIT BUFFER START_RDATA DW ? ; INDEX TO FIRST CHARACTER IN REC. BUFFER END_RDATA DW ? ; INDEX TO FIRST FREE SPACE IN REC. BUFFER ; BUFFER COUNTS SIZE_TDATA DW ? ; NUMBER OF CHARACTERS IN X-MIT BUFFER SIZE_RDATA DW ? ; NUMBER OF CHARACTERS IN REC. BUFFER ; BUFFERS TDATA DB S_SIZE DUP(?) ; SEND BUFFER RDATA DB R_SIZE DUP(?) ; RECEIVE BUFFER SP_TAB ENDS ; SP_TAB EQUATES ; WE HAVE TO USE THESE BECAUSE OF PROBLEMS WITH STRUC EOVFLOW EQU ERROR_BLOCK ; BUFFER OVERFLOWS EOVRUN EQU ERROR_BLOCK+2 ; RECEIVE OVERRUNS EBREAK EQU ERROR_BLOCK+4 ; BREAK CHARS EFRAME EQU ERROR_BLOCK+6 ; FRAMING ERRORS EPARITY EQU ERROR_BLOCK+8 ; PARITY ERRORS EXMIT EQU ERROR_BLOCK+10 ; TRANSMISSION ERRORS EDSR EQU ERROR_BLOCK+12 ; DATA SET READY ERRORS ECTS EQU ERROR_BLOCK+14 ; CLEAR TO SEND ERRORS DLL EQU DATREG ; LOW DIVISOR LATCH DLH EQU IER ; HIGH DIVISOR LATCH PAGE ; ; put the data in the DGROUP segment ; far calls enter with DS pointing to DGROUP ; DGROUP GROUP _DATA _DATA SEGMENT PUBLIC 'DATA' ; DIV50PC EQU 2304 ; DIVISOR FOR 50 BAUD (PC,XT) DIV50JR EQU 2237 ; DIVISOR FOR 50 BAUD (JR) DIV50 DW 2304 ; ACTUAL DIVISOR FOR 50 BAUD IN USE CURRENT_AREA DW AREA1 ; CURRENTLY SELECTED AREA ; DATA AREAS FOR EACH PORT AREA1 SP_TAB <1,INT_COM1,IRQ4,NIRQ4,EOI4> ; COM1 DATA AREA AREA2 SP_TAB <2,INT_COM2,IRQ3,NIRQ3,EOI3> ; COM2 DATA AREA AREA3 SP_TAB <3,INT_COM3,IRQ4,NIRQ4,EOI4> ; COM3 DATA AREA AREA4 SP_TAB <4,INT_COM4,IRQ3,NIRQ3,EOI3> ; COM4 DATA AREA _DATA ENDS PAGE ; COM_TEXT SEGMENT PARA PUBLIC 'CODE' ASSUME CS:COM_TEXT,DS:DGROUP,ES:NOTHING PUBLIC _select_port PUBLIC _save_com PUBLIC _install_com PUBLIC _restore_com PUBLIC _open_com PUBLIC _close_com PUBLIC _dtr_on PUBLIC _dtr_off PUBLIC _r_count PUBLIC _s_count PUBLIC _receive_com PUBLIC _send_com PUBLIC _sendi_com PUBLIC _send_local PUBLIC _break_com PUBLIC _com_errors PUBLIC _modem_status IFDEF DEBUG PUBLIC INST2, INST4 PUBLIC OC1, OC2, OCX PUBLIC DTRON1, DTRON6, DTRONF, DTRONS, DTRONX PUBLIC L11, LI3, LI4 PUBLIC RCVX PUBLIC L4A, L44 PUBLIC WaitN, WaitN1, WaitN2 PUBLIC SENDII, SENDII2, SENDII3, SENDII4, SENDIIX PUBLIC INT_COMMON, REPOLL, INT_END PUBLIC LSTAT_INT PUBLIC MSTAT_INT PUBLIC TX_INT, TXI1, TXI2, TXI3, TXI9 PUBLIC RX_INT, RXI0, RXI1, RXI2, RXI6, RXIX ENDIF PAGE ; ; Notes, thoughts and explainations by Bill Plummer. These are intended to ; help those of you who would like to make modifications. ; Here's the order of calls in UUPC. The routines in COMM.ASM are called ; from ulib.c. ; First (when a line in system has been read?), ulib&openline calls ; select_port() ; Sets up CURRENT_AREA ; then, save_com() ; Save INT vector ; then, install_com() ; Init area, hook INT ; then, open_com(&cmd, 'D', 'N', STOP*T, 'D') ; Init UART, clr bufs ; then, dtr_on(). ; At that point the line is up and running. UUPC calls ulib&sread() ; which calls, receive_com(); ; And UUPC calls ulib&swrite() ; which calls, send_com(); ; To cause an error that the receiver will see, UUPC calls ulib&ssendbrk(); ; which calls, break_com(); ; When all done with the line, UUPC calls ulib&closeline() ; which calls, dtr_off(); ; then, close_com(); ; then, restore_com(); ; Unhook INT ; and, stat_errors(); ; Note: On the PC COM1 and COM3 share IRQ4, while COM2 and COM4 share IRQ3. ; BUT, only one device on a given IRQ line can be active at a time. So it is ; sufficient for UUPC to hook whatever IRQ INT its modem is on as long as it ; unhooks it when it is done with that COM port. COMM cannot be an installed ; device driver since it must go away when UUPC is done so that other devices ; on the same INTs will come back to life. Also, it is OK to have a static ; CURRENT_AREA containing the current area that UUPC is using. ; Note about using the NS16550A UART chip's FIFOs. These are operated as ; silos. In other words when an interrupt happens because the receive(send) ; FIFO is nearly full(empty), as many bytes as possible are transferred and ; the interrupt dismissed. Thus, the interrupt load is lowered. ; Concerning the way the comm line is brought up. ; There are two basic cases, the Direct ('D') connection and the Modem ('M') ; connection. For either UUPC calls dtr_on_com() to bring up the line. This ; causes Data Terminal Ready (DTR) and Request To Send (RTS) to be set. Note ; this is OK for a simple 3-wire link but may be REQUIRED for a COM port ; connected to an external modem. ; The difference between a D connection and an M connection is ; whether or not the PC can expect any signals back from the modem. If ; there is a simple 3-wire link, Data Set Ready will be floating. ; (Actually, some wise people jumper Data Terminal Read back to Data ; Set Ready so the PC sees its own DTR appear as DSR.) UUPC should be ; able to handle the simplest cable as a design feature. So both D and ; M connections send out DTR and RTS, but only the M connection expects ; a modem to respond. ; Then, if it is full modem connection (M), we wait for a few ; seconds hoping that both Data Set Ready (DSR) and Clear To Send (CTS) ; will come up. If they don't, the associated counters are incremented ; for subsequent printing in the error log. Note that no error is ; reported from COMM to UUPC at this point, although this would be a ; good idea. Instead UUPC storms ahead with its output trying to ; establish a link, but the output is never sent due to one of the ; control signals being false. UUPC could check the modem status using ; a call which has been installed just for this purpose. ; Note, if you are going to connect your PC running UUPC to, ; say, a mainframe and you need hardware flow control (i.e., RTS-CTS ; handshaking), use a Modem connection. Using a simple 3-wire cable ; forbids hardware flow control and UUPC must be instructed to use a ; Direct connection. Refer to comments in the sample MODEM file (*.MDM) ; on how to make this selection. ; References used in designing the revisions to COMM.ASM: ; 1. The UNIX fas.c Driver code. ; 2. SLIP8250.ASM from the Clarkson driver set. ; 3. NS16550A data sheet and AN-491 from National Semiconductor. ; 4. Bell System Data Communications, Technical Reference for ; Data Set 103A, Interface Specification, February, 1967 ; 5. Network mail regarding V.24 ; 6. Joe Doupnik, Utah State, primary author of MS-Kermit PAGE ; ; ; SELECT WHICH PORT IS TO BE "ACTIVE" ; [bp+6] = port number _select_port PROC FAR push bp mov bp,sp mov AX,[bp+6] ; get aguement CMP AL,1 ; Port 1? JE SP1 ; Yes CMP AL,2 ; Port 2? JE SP2 ; Yes CMP AL,3 ; Port 3? JE SP3 ; Yes CMP AL,4 ; Port 4? JE SP4 ; Yes INT 20H ; N.O.T.A. ????? Halt for debugging! ; Assume port 1 if continued SP1: MOV AX,OFFSET DGROUP:AREA1 ; SELECT COM1 DATA AREA JMP SHORT SPX ; CONTINUE SP2: MOV AX,OFFSET DGROUP:AREA2 ; SELECT COM2 DATA AREA JMP SHORT SPX ; CONTINUE SP3: MOV AX,OFFSET DGROUP:AREA3 ; SELECT COM3 DATA AREA JMP SHORT SPX ; CONTINUE SP4: MOV AX,OFFSET DGROUP:AREA4 ; SELECT COM4 DATA AREA ;Fall into SPX SPX: MOV CURRENT_AREA,AX ; SET SELECTION IN MEMORY mov sp,bp pop bp RET _select_port ENDP PAGE ; ; ; SAVE ORIGINAL COM VECTOR ; _save_com PROC FAR push bp mov bp,sp push si PUSH ES ; SAVE EXTRA SEGMENT MOV SI,CURRENT_AREA ; SI POINTS TO DATA AREA MOV AREA1.INT_HNDLR,OFFSET INT_HNDLR1 MOV AREA2.INT_HNDLR,OFFSET INT_HNDLR2 MOV AREA3.INT_HNDLR,OFFSET INT_HNDLR3 MOV AREA4.INT_HNDLR,OFFSET INT_HNDLR4 ; Save old interrupt vector MOV AH,35H ; FETCH INTERRUPT VECTOR CONTENTS MOV AL,INT_COM[SI] ; INTERRUPT NUMBER INT DOS ; DOS 2 FUNCTION MOV OLD_COM_OFF[SI],BX ; SAVE MOV BX,ES ; ES:BX MOV OLD_COM_SEG[SI],BX ; FOR LATER RESTORATION POP ES ; RESTORE ES pop si mov sp,bp pop bp RET ; DONE _save_com ENDP PAGE ; ; ; INSTALL_COM: INSTALL THE ACTIVE PORT ; ; SET UART PORTS FROM RS-232 BASE IN ROM BIOS DATA AREA ; INITIALIZE PORT CONSTANTS AND ERROR COUNTS ; INSTALL INTERRUPT VECTOR ; ; return ax=1 on success ax=0 on failure ; _install_com PROC FAR push bp mov bp,sp push si PUSH BX PUSH CX PUSH DX MOV SI,CURRENT_AREA ; SI POINTS TO DATA AREA PUSH ES ; SAVE EXTRA SEGMENT CMP INSTALLED[SI],1 ; Is port installed on this machine? JNE INSTOK ; NO, CONTINUE JMP INST9 ; ELSE JUMP IF ALREADY INSTALLED ; ; CLEAR ERROR COUNTS INSTOK: MOV WORD PTR EOVFLOW[SI],0 ; BUFFER OVERFLOWS MOV WORD PTR EOVRUN[SI],0 ; RECEIVE OVERRUNS MOV WORD PTR EBREAK[SI],0 ; BREAK CHARS MOV WORD PTR EFRAME[SI],0 ; FRAMING ERRORS MOV WORD PTR EPARITY[SI],0 ; PARITY ERRORS MOV WORD PTR EXMIT[SI],0 ; TRANSMISSION ERRORS MOV WORD PTR EDSR[SI],0 ; DATA SET READY ERRORS MOV WORD PTR ECTS[SI],0 ; CLEAR TO SEND ERRORS ; SENSE PC TYPE AND SET DIVISOR ACCORDINGLY MOV BX,ROM ; HIGH ROM SEGMENT MOV ES,BX ; TO ES ASSUME ES:ROM MOV DIV50,DIV50PC ; ASSUME PC OR XT CMP ROMID,0FDH ; IS IT A PCjr? JNE INST0 ; JUMP IF NOT MOV DIV50,DIV50JR ; ELSE SET JR DIVISOR ; SET UART PORT ADDRESSES INST0: MOV BX,RBDA ; ROM BIOS DATA AREA MOV ES,BX ; TO ES ASSUME ES:RBDA ; ; Map port number (COMx) into IO Address using the RS232_Base[x] table in ; the BIOS data area. If any of the ports is missing there should be a ; zero in the table for this COM port. BIOS startup routines pack the table ; so that if you have a COM4 but no COM3, 2E8 will be found in 40:4 and 0 ; will be in 40:6. ; N.B. The exact IO address in 40:x is irrelevant and may well be something ; other than the "standard" values if specially designed hardware is used. ; To minimize flack, we will use the standard value if the slot in the table ; is 0. The bad side effect of this is that (in the standard losing case of ; a COM4 but no COM3) both COM3 and COM4 will reference the hardware at 2E8. CMP PORT[SI],1 ; PORT 1? JE INST3F8 ; Yes CMP PORT[SI],2 ; PORT 2? JE INST2F8 ; Yes CMP PORT[SI],3 ; PORT 3? JE INST3E8 ; Yes CMP PORT[SI],4 ; PORT 4? JE INST2E8 ; Yes INT 20H ; NOTA. (Caller is screwed up badly) INST3F8:MOV AX,3F8H ; Standard COM1 location CMP RS232_BASE+0,0000H ; We have information? JE INST2 ; No --> Use default MOV AX,RS232_BASE+0 ; Yes --> Use provided info JMP SHORT INST2 ; CONTINUE INST2F8:MOV AX,2F8H ; Standard COM2 location CMP RS232_BASE+2,0000H ; We have information? JE INST2 ; No --> Use default MOV AX,RS232_BASE+2 ; Yes --> Use provided info JMP SHORT INST2 ; CONTINUE INST3E8:MOV AX,3E8H ; Standard COM3 location CMP RS232_BASE+4,0000H ; We have information? JE INST2 ; No --> Use default MOV AX,RS232_BASE+4 ; Yes --> Use provided info JMP SHORT INST2 ; CONTINUE INST2E8:MOV AX,2E8H ; Standard COM4 location CMP RS232_BASE+6,0000H ; We have information? JE INST2 ; No --> Use default MOV AX,RS232_BASE+6 ; Yes --> Use provided info ; Fall into INST2 ; Now we have an IO address for the COMx that we want to use. If it is ; anywhere in RS232_Base, we know that it has been check and is OK to use. ; So, even if my 2E8 (COM4) appears in 40:6 (normally for COM3), I can use ; it. INST2: CMP AX,RS232_BASE ; INSTALLED? JE INST2A ; JUMP IF SO CMP AX,RS232_BASE+2 ; INSTALLED? JE INST2A ; JUMP IF SO CMP AX,RS232_BASE+4 ; INSTALLED? JE INST2A ; JUMP IF SO CMP AX,RS232_BASE+6 ; INSTALLED? JNE INST666 ; JUMP IF NOT ; Fall into INST2A INST2A: MOV BX,DATREG ; OFFSET OF TABLE OF PORTS MOV CX,7 ; LOOP SIX TIMES INST3: MOV WORD PTR [SI][BX],AX ; SET PORT ADDRESS INC AX ; NEXT PORT ADD BX,2 ; NEXT WORD ADDRESS LOOP INST3 ; RS232 BASE LOOP MOV DX,FCR[SI] ; Get FIFO Control Register MOV AL,FIFO_INIT OUT DX,AL ; Try to initialize the FIFO MOV DX,IIR[SI] ; Get interrupt ID register IN AL,DX ; See how the UART responded AND CL,FIFO_ENABLED ; Keep only these bits MOV CX,1 ; Assume chunk size of 1 for 8250 case CMP AL,FIFO_ENABLED ; See if 16550A JNE INST4 ; Jump if not IFE (FIFO_SETUP AND FIFO_SZ_MASK) MOV CX,FIFO_LEN-FIFO_LEN ELSEIFE (FIFO_SETUP AND FIFO_SZ_MASK - FIFO_SZ_4) MOV CX,FIFO_LEN-4 ELSEIFE (FIFO_SETUP AND FIFO_SZ_MASK - FIFO_SZ_8) MOV CX,FIFO_LEN-8 ELSEIFE (FIFO_SETUP AND FIFO_SZ_MASK - FIFO_SZ_14) MOV CX,FIFO_LEN-14 ENDIF INST4: MOV UART_SILO_LEN[SI],CL ; Save chunk size MOV AL,FIFO_CLEAR OUT DX,AL MOV AH,25H ; SET INTERRUPT VECTOR CONTENTS MOV AL,INT_COM[SI] ; INTERRUPT NUMBER MOV DX,INT_HNDLR[SI] ; OUR INTERRUPT HANDLER [WWP] PUSH DS ; SAVE DATA SEGMENT PUSH CS ; COPY CS POP DS ; TO DS INT DOS ; DOS FUNCTION POP DS ; RECOVER DATA SEGMENT ; PORT INSTALLED INST9: MOV AX,1 JMP SHORT INSTX ; PORT NOT INSTALLED INST666:MOV AX,0 ;Fall into INSTX ; Common exit INSTX: MOV INSTALLED[SI],AL ; Indicate whether installed or not POP DX POP CX POP BX POP ES pop si mov sp,bp pop bp RET _install_com ENDP PAGE ; ; ; RESTORE ORIGINAL INTERRUPT VECTOR ; _restore_com PROC FAR push bp mov bp,sp push si PUSH BX MOV SI,CURRENT_AREA ; SI POINTS TO DATA AREA MOV INSTALLED[SI],0 ; PORT IS NO LONGER INSTALLED MOV AH,25H ; SET INTERRUPT VECTOR FUNCTION MOV AL,INT_COM[SI] ; INTERRUPT NUMBER MOV DX,OLD_COM_OFF[SI] ; OLD OFFSET TO DX MOV BX,OLD_COM_SEG[SI] ; OLD SEG PUSH DS ; SAVE DS MOV DS,BX ; TO DS INT DOS ; DOS FUNCTION POP DS ; RECOVER DS POP BX pop si mov sp,bp pop bp RET _restore_com ENDP PAGE ; ; ; OPEN_COM ON CURRENT PORT ; ; CLEAR BUFFERS ; RE-INITIALIZE THE UART ; ENABLE INTERRUPTS ON THE 8259 INTERRUPT CONTROL CHIP ; ; [bp+6] = BAUD RATE ; [bp+8] = CONNECTION: M(ODEM), D(IRECT) ; [bp+10] = PARITY: N(ONE), O(DD), E(VEN), S(PACE), M(ARK) ; [bp+12] = STOP BITS: 1, 2 ; [bp+14] = XON/XOFF: E(NABLED), D(ISABLED) ; _open_com PROC FAR push bp mov bp,sp push si PUSHF PUSH BX PUSH DX MOV SI,CURRENT_AREA ; SI POINTS TO DATA AREA CLI ; INTERRUPTS OFF mov ax,[bp+6] MOV BAUD_RATE[SI],AX ; SET mov bh,[bp+8] MOV CONNECTION[SI],BH ; ARGS mov bl,[bp+10] MOV PARITY[SI],BL ; IN mov ch,[bp+12] MOV STOP_BITS[SI],CH ; MEMORY mov cl,[bp+14] MOV XON_XOFF[SI],CL ; RESET FLOW CONTROL MOV HOST_OFF[SI],0 ; HOST FLOWING MOV PC_OFF[SI],0 ; PC FLOWING MOV URGENT_SEND[SI],0 ; No flow ctl which must go out MOV SEND_OK[SI],0 ; DTR&CTS are not on yet ; RESET BUFFER COUNTS AND POINTERS MOV START_TDATA[SI],0 MOV END_TDATA[SI],0 MOV START_RDATA[SI],0 MOV END_RDATA[SI],0 MOV SIZE_TDATA[SI],0 MOV SIZE_RDATA[SI],0 TEST INSTALLED[SI],1 ; PORT INSTALLED? JNZ OC1 ; SKIP IF SO JMP OCX ; ELSE ABORT ; RESET THE UART OC1: MOV DX,MCR[SI] ; Modem Control Register MOV AL,0 ; Clr DTR, RTS, OUT1, OUT2 & LOOPBACK OUT DX,AL MOV AL,30H ; Be sure DSR and CTS are ON. Some MOV DX,MSR[SI] ; modems need this (I don't know why!) OUT DX,AL ; Clear Loopback, etc. JMP $+2 ; I/O DELAY FOR JR IN AL,DX ; Read to get the delta bits & clr int AND AL,30H ; Leave the two critical bits CMP AL,30H ; Both on? JNE OC2 ; No. Leave SEND_OK zero. MOV SEND_OK[SI],1 ; Allow TX_INT to send out data OC2: MOV DX,FCR[SI] ; I/O Address of FIFO control register MOV AL,FIFO_CLEAR ; Disable FIFOs OUT DX,AL ; Non-16550A chips will ignore this MOV DX,LSR[SI] ; RESET LINE STATUS CONDITION IN AL,DX JMP $+2 ; I/O DELAY FOR JR MOV DX,DATREG[SI] ; RESET RECEIVE DATA CONDITION IN AL,DX JMP $+2 ; I/O DELAY FOR JR MOV DX,MSR[SI] ; RESET MODEM DELTAS AND CONDITIONS IN AL,DX ; CONVERT PASSED BAUD RATE TO UART DIVISOR MOV AX,50 ; 50 BAUD MUL DIV50 ; TIMES ITS DIVISOR DIV BAUD_RATE[SI] ; OTHER SPEEDS ARE PROPORTIONAL MOV BX,AX ; RESULT TO BX ; SET UART DIVISOR MOV DX,LCR[SI] ; LINE CONTROL REGISTER MOV AL,80H ; HI BIT ON OUT DX,AL ; SET DLAB = 1 JMP $+2 ; I/O DELAY FOR JR MOV DX,WORD PTR DLL[SI] ; LEAST SIGNIFICANT BYTE MOV AL,BL ; LSB FROM TABLE OUT DX,AL ; SET LSB ON UART JMP $+2 ; I/O DELAY FOR JR MOV DX,WORD PTR DLH[SI] ; MOST SIGNIFICANT BYTE MOV AL,BH ; MSB FROM TABLE OUT DX,AL ; SET MSB ON UART JMP $+2 ; I/O DELAY FOR JR ; SET PARITY AND NUMBER OF STOP BITS MOV AL,03H ; NONE OR SPACE PARITY IS THE DEFAULT CMP PARITY[SI],'O' ; ODD PARITY REQUESTED? JNE P1 ; JUMP IF NOT MOV AL,0AH ; SELECT ODD PARITY JMP SHORT P3 ; CONTINUE ; P1: CMP PARITY[SI],'E' ; EVEN PARITY REQUESTED? JNE P2 ; JUMP IF NOT MOV AL,1AH ; SELECT EVEN PARITY JMP SHORT P3 ; CONTINUE ; P2: CMP PARITY[SI],'M' ; MARK PARITY REQUESTED? JNE P3 ; JUMP IF NOT MOV AL,2AH ; SELECT MARK PARITY P3: TEST STOP_BITS[SI],2 ; 2 STOP BITS REQUESTED? JZ STOP1 ; NO OR AL,4 ; YES STOP1: MOV DX,LCR[SI] ; LINE CONTROL REGISTER OUT DX,AL ; SET UART PARITY MODE AND DLAB=0 ; Initialize the FIFOs MOV DX,FCR[SI] ; I/O Address of FIFO control register MOV AL,FIFO_INIT ; Clear FIFOs, set size, enable FIFOs OUT DX,AL ; Non-16550A chips will ignore this ; ENABLE INTERRUPTS ON 8259 AND UART IN AL,INTA01 ; SET ENABLE BIT ON 8259 AND AL,NIRQ[SI] OUT INTA01,AL MOV DX,IER[SI] ; Interrupt enable register MOV AL,0FH ; Line & Modem status, recv, send OUT DX,AL ; Enable all interrupts JMP $+2 ; I/O DELAY FOR JR OCX: STI ; INTERRUPTS ON POP DX POP BX POPF pop si mov sp,bp pop bp RET ; DONE _open_com ENDP PAGE ; ; ; CLOSE_COM - TURNS OFF INTERRUPTS FROM THE COMMUNICATIONS PORT ; _close_com PROC FAR push bp mov bp,sp push si PUSH DX MOV SI,CURRENT_AREA ; SI POINTS TO DATA AREA TEST INSTALLED[SI],1 ; PORT INSTALLED? JZ CCX ; ABORT IF NOT ; TURN OFF UART and clear FIFOs in NS16550A MOV DX,IER[SI] MOV AL,0 OUT DX,AL ; No interrupts right now, please MOV AL,FIFO_CLEAR OUT DX,AL ; TURN OFF 8259 MOV DX,INTA01 IN AL,DX OR AL,IRQ[SI] JMP $+2 ; DELAY FOR AT OUT DX,AL CCX: POP DX pop si mov sp,bp pop bp RET _close_com ENDP PAGE ; ; ; DTR_OFF - TURNS OFF DTR TO TELL MODEMS THAT THE TERMINAL HAS GONE AWAY ; AND TO HANG UP THE PHONE ; _dtr_off PROC FAR push bp mov bp,sp push si PUSHF ; SAVE FLAGS PUSH AX ; SAVE REGS PUSH DX PUSH SI MOV SI,CURRENT_AREA ; SI POINTS TO DATA AREA TEST INSTALLED[SI],1 ; PORT INSTALLED? JZ DFX ; ABORT IF NOT MOV DX,MCR[SI] ; Modem Control Register IN AL,DX ; See if it is on AND AL,1 ; Just look at the DTR bit JE DFX ; Not on. Don't clr. Don't wait. MOV AL,08H ; DTR off, RTS off, OUT2 on OUT DX,AL DFX: POP SI ; RECOVER REGS POP DX POP AX POPF ; RECOVER FLAGS pop si mov sp,bp pop bp RET _dtr_off ENDP PAGE ; ; ; DTR_ON - TURNS DTR ON ; _dtr_on PROC FAR push bp mov bp,sp push si PUSHF ; SAVE FLAGS PUSH AX ; SAVE REGS PUSH BX PUSH DX PUSH SI MOV SI,CURRENT_AREA ; SI POINTS TO DATA AREA TEST INSTALLED[SI],1 ; PORT INSTALLED? JZ DTRONF ; Suppress output if not ; Tell modem we are ready and want to send with line idle MOV DX,MCR[SI] ; Modem Control Register MOV AL,00001011B ; OUT 2, RTS, DTR OUT DX,AL JMP $+2 ; I/O DELAY FOR JR ; Wait for awhile to give the modem time to respond MOV AH,2CH ; Get time (H:M:S:H to CH:CL:DH:DL) INT 21H MOV BX,DX ; Save seconds&hundreths ADD BH,05 ; Allow 5 seconds wait (actually 4-6) CMP BH,60 ; Wrap around check JL DTRON1 ; No wrap SUB BH,60 DTRON1: CMP SEND_OK[SI],1 ; Did the modem come up? JE DTRONS ; Yes. Both DSR and CTS are true. INT 21H ; Get the time again CMP DX,BX ; Current time is passed the deadline? JB DTRON1 ; No, keep checking 'til time runs out MOV AX,200H ; 2 Seconds CALL WaitN ; V.24 says 2 sec hi before data CMP CONNECTION[SI],'D' ; Direct connection (no DSR,CTS)? JE DTRONS ; Skip DSR, CTS check ; Modem failed to come up. Bump counts that tell why. MOV DX,MSR[SI] ; MODEM STATUS REGISTER IN AL,DX ; GET MODEM STATUS TEST AL,20H ; DATA SET READY? JNZ DTRON6 ; Yup. INC WORD PTR EDSR[SI] ; BUMP ERROR COUNT DTRON6: TEST AL,10H ; Clear To Send? JNZ DTRONF ; That's OK. INC WORD PTR ECTS[SI] ; BUMP ERROR COUNT - WE TIMED OUT ; Fall into DTRONF ; Failure return DTRONF: MOV SEND_OK[SI],0 ; Block output data flow at TX_INT JMP SHORT DTRONX ; Successful return DTRONS: MOV SEND_OK[SI],1 ; Enable output ; Fall into DTRONX DTRONX: POP SI ; RECOVER REGS POP DX POP BX POP AX POPF ; RECOVER FLAGS pop si mov sp,bp pop bp RET _dtr_on ENDP PAGE ; ; ; Wait for specified time using the 18.2 ticks/second clock ; ; Call: AX has seconds,hundreths ; CALL WaitN ; Return: At least the requested time has passed ; WaitN PROC NEAR PUSH BP MOV BP,SP PUSH AX PUSH BX PUSH CX PUSH DX PUSH AX ; Save a copy of the arg MOV AH,2CH ; Get time (H:M:S:H to CH:CL:DH:DL) INT DOS POP BX ; Recover S:H arg ADD BX,DX ; Determine deadline CMP BL,100 ; Wrap around? JL WaitN1 ; No SUB BL,100 ; Yes. Subtract 100 hundreths INC BH ; And add a second WaitN1: CMP BH,60 ; Wrap around check JL WaitN2 ; No wrap SUB BH,60 ; Forget about Days and Hours WaitN2: INT DOS ; Get the time again CMP DX,BX ; Is current time after the deadline? JB WaitN2 ; No, keep checking 'til time runs out POP DX POP CX POP BX POP CX MOV SP,BP POP BP RET WaitN ENDP PAGE ; ; ; R_COUNT - RETURNS NUMBER OF BYTES IN THE RECEIVE BUFFER IN AX ; total in DX ; _r_count PROC FAR push bp mov bp,sp push si PUSHF PUSH SI MOV SI,CURRENT_AREA ; SI POINTS TO DATA AREA MOV AX,0 ; NOTHING RECEIVED IF NOT INSTALLED mov dx,R_SIZE TEST INSTALLED[SI],1 ; PORT INSTALLED? JZ RCX ; ABORT IF NOT MOV AX,SIZE_RDATA[SI] ; GET NUMBER OF BYTES USED RCX: POP SI POPF pop si mov sp,bp pop bp RET _r_count ENDP PAGE ; ; ; RECEIVE - RETURNS THE NEXT CHARACTER FROM THE RECEIVE BUFFER IN AL ; AND REMOVES IT FROM THE BUFFER ; THE PARITY BIT IS STRIPPED OFF if not in Parity mode ; Returns AX: -1 if port not installed or no characters available ; or AX: the next character ; _receive_com PROC FAR push bp mov bp,sp push si PUSHF ; SAVE FLAGS PUSH BX ; SAVE REGS PUSH SI MOV SI,CURRENT_AREA ; SI POINTS TO DATA AREA mov ax,-1 ; -1 if bad call TEST INSTALLED[SI],1 ; PORT INSTALLED? JZ RCVX ; ABORT IF NOT CMP SIZE_RDATA[SI],0 ; ANY CHARACTERS? JE RCVX ; ABORT IF NOT ; GOOD CALL mov ah,0 ; good call MOV BX,START_RDATA[SI] ; GET POINTER TO OLDEST CHAR MOV AL,RDATA[SI][BX] ; GET CHAR FROM BUFFER CMP PARITY[SI],'N' ; ARE WE RUNNING WITH NO PARITY? LBA JE L11 ; IF SO, DON'T STRIP HIGH BIT LBA AND AL,7FH ; STRIP PARITY BIT L11: INC BX ; BUMP START_RDATA AND BX,R_SIZE-1 ; Ring the pointer MOV START_RDATA[SI],BX ; SAVE THE NEW START_RDATA VALUE DEC SIZE_RDATA[SI] ; ONE LESS CHARACTER CMP XON_XOFF[SI],'E' ; FLOW CONTROL ENABLED? JNE RCVX ; DO NOTHING IF DISABLED CMP HOST_OFF[SI],1 ; HOST TURNED OFF? JNE RCVX ; JUMP IF NOT CMP SIZE_RDATA[SI],R_SIZE/16; RECEIVE BUFFER NEARLY EMPTY? JGE RCVX ; DONE IF NOT MOV HOST_OFF[SI],0 ; TURN ON HOST IF SO PUSH AX ; SAVE RECEIVED CHAR MOV AL,CONTROL_Q ; TELL HIM TO TALK LI3: CLI ; TURN OFF INTERRUPTS CMP URGENT_SEND[SI],1 ; Previous send still in progress? JNE LI4 ; No. There is space now. STI ; Yes. Wait for interrupt to take it. JMP SHORT LI3 ; Loop 'til it's gone LI4: CALL SENDII ; SEND IMMEDIATELY INTERNAL STI ; INTERRUPTS BACK ON POP AX ; RESTORE RECEIVED CHAR RCVX: POP SI ; RECOVER REGS POP BX POPF ; RECOVER FLAGS pop si mov sp,bp pop bp RET _receive_com ENDP PAGE ; ; ; S_COUNT - RETURNS IN AX THE AMOUNT OF FREE SPACE ; REMAINING IN THE TRANSMIT BUFFER ; DX total size ; N.B. The free space might be negative (-1) if the buffer was full and then ; the program called SENDI or RX_INT required sending a control-S to squelch ; the remote sender. Return 0 in this case. ; _s_count PROC FAR push bp mov bp,sp push si PUSHF PUSH SI MOV SI,CURRENT_AREA ; SI POINTS TO DATA AREA MOV AX,0 ; NO SPACE LEFT IF NOT INSTALLED mov dx,S_SIZE-1 ; Leave 1 byte for a SENDII call TEST INSTALLED[SI],1 ; PORT INSTALLED? JZ SCX ; ABORT IF NOT MOV AX,S_SIZE-1 ; GET THE SIZE OF THE X-MIT BUFFER SUB AX,SIZE_TDATA[SI] ; SUBTRACT THE NUMBER OF BYTES USED JGE SCX ; Avoid returning negative number XOR AX,AX ; Return 0 SCX: POP SI ; RECOVER SI POPF ; RESTORE FLAGS pop si mov sp,bp pop bp RET _s_count ENDP PAGE ; ; ; SEND - SEND A CHARACTER ; [bp+6] = char ; _send_com PROC FAR push bp mov bp,sp push si PUSHF ; SAVE FLAGS PUSH AX ; SAVE REGS PUSH BX PUSH DX PUSH SI MOV SI,CURRENT_AREA ; SI POINTS TO DATA AREA TEST INSTALLED[SI],1 ; PORT INSTALLED? JZ L44 ; ABORT IF NOT SENDC1: CMP SIZE_TDATA[SI],S_SIZE-1 ; BUFFER FULL? (Leave room for SENDII) JGE SENDC1 ; Wait for interrupts to empty buffer L4A: MOV BX,END_TDATA[SI] ; BX POINTS TO FREE SPACE MOV AL,[BP+6] ; Character to send MOV TDATA[SI][BX],AL ; MOVE CHAR TO BUFFER INC BX ; INCREMENT END_TDATA AND BX,S_SIZE-1 ; Ring the pointer MOV END_TDATA[SI],BX ; SAVE NEW END_TDATA INC SIZE_TDATA[SI] ; ONE MORE CHARACTER IN X-MIT BUFFER MOV DX,IER[SI] ; INTERRUPT ENABLE REGISTER IN AL,DX ; GET IT TEST AL,2 ; SEE IF TX INTERRUPTS ARE ENABLED JNZ L44 ; JUMP IF SO CMP SEND_OK[SI],1 ; See if Data Set Ready & CTS are on JNE L44 ; No. Still can't enable TX ints TEST PC_OFF[SI],1 ; Were we stopped by a ^S from host? JNZ L44 ; Yes. Don't enable interrupts yet. MOV AL,0FH ; IF NOT THEN RCV, TX, LINE & Modem OUT DX,AL ; ARE ENABLED. L44: POP SI ; RESTORE REGS POP DX POP BX POP AX POPF ; RESTORE FLAGS pop si mov sp,bp pop bp RET ; DONE _send_com ENDP PAGE ; ; ; SENDI - SEND A CHARACTER IMMEDIATELY ; [bp+6] = char to send ; _sendi_com PROC FAR push bp mov bp,sp push si mov al,[bp+6] PUSHF ; SAVE FLAGS PUSH SI MOV SI,CURRENT_AREA ; SI POINTS TO DATA AREA TEST INSTALLED[SI],1 ; PORT INSTALLED? JZ LQ44 ; ABORT IF NOT SENDI3: CLI ; TURN OFF INTERRUPTS CMP URGENT_SEND[SI],1 ; Previous send still in progress? JNE SENDI4 ; No. There is space now. STI ; Yes. Wait for interrupt to take it. JMP SHORT SENDI3 ; Loop 'til it's gone SENDI4: CALL SENDII ; CALL INTERNAL SEND IMMEDIATE STI ; INTERRRUPTS BACK ON LQ44: POP SI ; RESTORE REGS POPF ; RESTORE FLAGS pop si mov sp,bp pop bp RET ; DONE _sendi_com ENDP PAGE ; ; ; INTERNAL ROUTINE -- Called from process level and (receive) interrupt level ; DEPENDS ON CALLER TO KEEP INTERRUPTS CLEARED AND SET SI ; SENDI - SEND A CHARACTER IMMEDIATELY (PUT AT BEGINNING OF QUEUE) ; AL = CHAR TO WRITE ; SENDII PROC NEAR PUSH BX PUSH DX ; SAVE DX CMP SIZE_TDATA[SI],S_SIZE ; BUFFER FULL? JB SENDII2 ; JUMP IF NOT INC WORD PTR EOVFLOW[SI] ; BUMP ERROR COUNT (Can this happen?) MOV BX,START_TDATA[SI] ; BX POINTS TO FIRST CHAR IN BUFFER MOV TDATA[SI][BX],AL ; CLOBBER FIRST CHAR IN BUFFER JMP SHORT SENDII4 SENDII2:MOV BX,START_TDATA[SI] ; BX POINTS TO FIRST CHAR IN BUFFER DEC BX ; BACKUP THE PTR CMP BX,-1 ; BEFORE BEGINNING? JNE SENDII3 ; JUMP IF NOT MOV BX,S_SIZE-1 ; POINT TO END IF SO SENDII3:MOV TDATA[SI][BX],AL ; MOVE CHAR TO BUFFER MOV START_TDATA[SI],BX ; SAVE NEW START_TDATA INC SIZE_TDATA[SI] ; ONE MORE CHARACTER IN X-MIT BUFFER MOV URGENT_SEND[SI],1 ; Flag high priority message SENDII4:MOV DX,IER[SI] ; INTERRUPT ENABLE REGISTER IN AL,DX ; GET IT TEST AL,2 ; SEE IF TX INTERRUPTS ARE ENABLED JNZ SENDIIX ; JUMP IF SO CMP SEND_OK[SI],1 ; See if Data Set Ready & CTS are on JNE SENDIIX ; No. Still can't enable TX ints MOV AL,0FH ; IF NOT THEN RCV, TX, LINE & Modem OUT DX,AL ; ARE ENABLED SENDIIX:POP DX ; RECOVER DX POP BX RET ; DONE SENDII ENDP PAGE ; ; ; S_LOCAL ; _send_local PROC FAR push bp mov bp,sp push si PUSHF ; SAVE FLAGS PUSH AX ; SAVE REGS PUSH BX PUSH SI MOV SI,CURRENT_AREA ; SI POINTS TO DATA AREA TEST INSTALLED[SI],1 ; PORT INSTALLED? JZ SLX ; ABORT IF NOT CLI ; INTERRUPTS OFF CMP SIZE_RDATA[SI],R_SIZE ; SEE IF ANY ROOM JB L13A ; SKIP IF ROOM INC WORD PTR EOVFLOW[SI] ; BUMP OVERFLOW COUNT JMP SHORT L14 ; PUNT L13A: MOV BX,END_RDATA[SI] ; BX POINTS TO FREE SPACE MOV AL,[BP+6] ; Get the byte to send MOV RDATA[SI][BX],AL ; Put into buffer INC BX ; INCREMENT END_RDATA POINTER AND BX,R_SIZE-1 ; Ring the pointer MOV END_RDATA[SI],BX ; SAVE VALUE INC SIZE_RDATA[SI] ; GOT ONE MORE CHARACTER L14: STI ; INTERRUPTS BACK ON SLX: POP SI ; RECOVER REGS POP BX POP AX POPF ; RECOVER FLAGS pop si mov sp,bp pop bp RET ; DONE _send_local ENDP PAGE ; ; ; BREAK - CAUSES A BREAK TO BE SENT OUT ON THE LINE ; _break_com PROC FAR push bp mov bp,sp push si PUSHF PUSH AX PUSH BX PUSH CX PUSH DX MOV SI,CURRENT_AREA ; SI POINTS TO DATA AREA TEST INSTALLED[SI],1 ; PORT INSTALLED? JZ BREAKX ; ABORT IF NOT MOV DX,LCR[SI] ; LINE CONTROL REGISTER IN AL,DX ; GET CURRENT SETTING JMP $+2 ; I/O DELAY FOR JR OR AL,40H ; TURN ON BREAK BIT OUT DX,AL ; SET IT ON THE UART MOV AX,25 ; 25/100 of a second CALL WaitN MOV DX,LCR[SI] ; LINE CONTROL REGISTER IN AL,DX ; GET CURRENT SETTING JMP $+2 ; I/O DELAY FOR JR AND AL,0BFH ; TURN OFF BREAK BIT OUT DX,AL ; RESTORE LINE CONTROL REGISTER BREAKX: POP DX ; RECOVER REGS POP CX POP BX POP AX POPF ; RECOVER FLAGS pop si mov sp,bp pop bp RET ; DONE _break_com ENDP PAGE ; ; COM_ERRORS - RETURN POINTER IN dx:ax TO ERROR COUNTS ; _com_errors PROC FAR push bp mov bp,sp mov ax,OFFSET DGROUP:CURRENT_AREA add ax,ERROR_BLOCK mov dx,ds mov sp,bp pop bp RET _com_errors ENDP PAGE ; ; ; _MODEM_STATUS - Returns the modem status register in AL ; ; Bits are: 0x80: -CD (Carrier Detect, inverted) ; 0x40: -RI (Ring Indicator, inverted) ; 0x20: -DSR (Data Set Ready, inverted) ; 0x10: -CTS (Clear to Send, inverted) ; 0x08: Delta Carrier Detect (CD changed) ; 0x04: Trailing edge of RI (RI went OFF) ; 0x02: Delta DSR (DSR changed) ; 0x01: Delta CTS (CTS changed) ; _modem_status PROC FAR push bp mov bp,sp PUSH DX PUSH SI MOV SI,CURRENT_AREA ; Point to block for selected port MOV DX,MSR[SI] ; IO Addr of Modem Status Register IN AL,DX ; Get the live value XOR AH,AH ; Flush unwanted bits POP SI POP DX mov sp,bp pop bp RET _modem_status ENDP PAGE ; ; ; INT_HNDLR1 - HANDLES INTERRUPTS GENERATED BY COM1: ; INT_HNDLR1 PROC FAR PUSH SI MOV SI,OFFSET DGROUP:AREA1 ; DATA AREA FOR COM1: JMP SHORT INT_COMMON ; CONTINUE ; ; INT_HNDLR2 - HANDLES INTERRUPTS GENERATED BY COM2: ; INT_HNDLR2 PROC FAR PUSH SI MOV SI,OFFSET DGROUP:AREA2 ; DATA AREA FOR COM2: JMP SHORT INT_COMMON ; CONTINUE ; ; INT_HNDLR3 - HANDLES INTERRUPTS GENERATED BY COM3: ; INT_HNDLR3 PROC FAR PUSH SI MOV SI,OFFSET DGROUP:AREA3 ; DATA AREA FOR COM3: JMP SHORT INT_COMMON ; CONTINUE ; ; INT_HNDLR4 - HANDLES INTERRUPTS GENERATED BY COM4: ; INT_HNDLR4 PROC FAR PUSH SI MOV SI,OFFSET DGROUP:AREA4 ; DATA AREA FOR COM4: ; Fall into INT_COMMON PAGE ; ; ; BODY OF INTERRUPT HANDLER ; INT_COMMON: PUSH AX PUSH BX PUSH CX PUSH DX PUSH DS MOV AX,DGROUP ; Offsets are relative to DGROUP [WWP] MOV DS,AX ; CLEAR THE INTERRUPT CONTROLLER FLAG MOV DX,INTA00 ; 8259 CONTROL PORT MOV AL,EOI[SI] ; SPECIFIC END OF INTERRUPT OUT DX,AL ; CLEAR FLAG ; FIND OUT WHERE INTERRUPT CAME FROM AND JUMP TO ROUTINE TO HANDLE IT REPOLL: MOV DX,IIR[SI] ; Interrupt Identification Register IN AL,DX TEST AL,1 ; Check the "no interrupt present" bit JNZ INT_END ; ON means we are done MOV BL,AL ; Put where we can index by it AND BX,000EH ; Ignore FIFO_ENABLED bits, etc. JMP WORD PTR CS:INT_DISPATCH[BX]; Go to appropriate routine INT_DISPATCH: DW MSTAT_INT ; 0: Modem status interrupt DW TX_INT ; 2: Transmitter interrupt DW RX_INT ; 4: Receiver interrupt DW LSTAT_INT ; 6: Line status interrupt DW REPOLL ; 8: (Future use by UART makers) DW REPOLL ; A: (Future use by UART makers) DW RX_INT ; C: FIFO Timeout. Drain data trapped in FIFO. DW REPOLL ; E: (Future use by UART makers) INT_END:POP DS POP DX POP CX POP BX POP AX POP SI IRET PAGE ; ; ; Line status interrupt ; LSTAT_INT: MOV DX,LSR[SI] ; Line status register IN AL,DX ; Read line status & bump error counts TEST AL,2 ; OVERRUN ERROR? JZ LSI1 ; JUMP IF NOT INC WORD PTR EOVRUN[SI] ; ELSE BUMP ERROR COUNT LSI1: TEST AL,4 ; PARITY ERROR? JZ LSI2 ; JUMP IF NOT INC WORD PTR EPARITY[SI] ; ELSE BUMP ERROR COUNT LSI2: TEST AL,8 ; FRAMING ERROR? JZ LSI3 ; JUMP IF NOT INC WORD PTR EFRAME[SI] ; ELSE BUMP ERROR COUNT LSI3: TEST AL,16 ; BREAK RECEIVED? JZ LSI4 ; JUMP IF NOT INC WORD PTR EBREAK[SI] ; ELSE BUMP ERROR COUNT LSI4: JMP REPOLL ; SEE IF ANY MORE INTERRUPTS ; ; Modem status interrupt ; MSTAT_INT: MOV DX,MSR[SI] ; Modem Status Register IN AL,DX ; Read status & clear interrupt CMP CONNECTION[SI],'D' ; Direct connection - ignore int JE MSI0 ; Just noise on DSR,CTS pins AND AL,30H ; Expose CTS and Data Set Ready CMP AL,30H ; Both on? JE MSI0 ; Yes. Enable output at TX_INT XOR AL,AL JMP SHORT MSI1 MSI0: MOV AL,1 MSI1: MOV SEND_OK[SI],AL ; Put where TXI and send_com can see MOV DX,IER[SI] ; Let a TX int happen for thoro chks MOV AL,0FH ; Line & modem sts, recv, send. OUT DX,AL JMP REPOLL ; Check for other interrupts PAGE ; ; ; Tranmit interrupt ; TX_INT: CMP SEND_OK[SI],1 ; Harware (CTS & DSR on) OK? JNE TXI9 ; No. Must wait 'til cable right! MOV CX,1 ; Transfer count for flow ctl CMP URGENT_SEND[SI],1 ; Flow control character to send? JE TXI3 ; Yes. Always send flow control. CMP PC_OFF[SI],1 ; Flow control (XON/XOFF) OK? JE TXI9 ; Stifled & not urgent. Forget it. TXI1: MOV CL,UART_SILO_LEN[SI] ; MAX size chunk (1 for simple 8250) ; Too bad there is no "Tranmitter FIFO Full" indication! CMP SIZE_TDATA[SI],CX ; SEE IF ANY MORE DATA TO SEND JG TXI2 ; UART is the limit MOV CX,SIZE_TDATA[SI] ; Buffer space limited. Use that. TXI2: JCXZ TXI9 ; No data, disable TX ints TXI3: MOV BX,START_TDATA[SI] ; BX POINTS TO NEXT CHAR. TO BE SENT MOV AL,TDATA[SI][BX] ; GET DATA FROM BUFFER MOV DX,DATREG[SI] ; DX EQUALS PORT TO SEND DATA TO OUT DX,AL ; SEND DATA INC BX ; INCREMENT START_TDATA AND BX,S_SIZE-1 ; Ring the pointer MOV START_TDATA[SI],BX ; SAVE START_TDATA DEC SIZE_TDATA[SI] ; ONE LESS CHARACTER IN X-MIT BUFFER LOOP TXI3 ; Keep going 'til silo is full MOV URGENT_SEND[SI],0 ; Tell process level we sent flow ctl JMP REPOLL ; IF NO DATA TO SEND, or can't send, RESET TX INTERRUPT AND RETURN TXI9: MOV DX,IER[SI] MOV AL,0DH ; Line & modem sts, recv, no send. OUT DX,AL JMP REPOLL PAGE ; ; ; Receive interrupt ; RX_INT: RXI0: MOV DX,LSR[SI] ; Line Status Register IN AL,DX ; Read it TEST AL,1 ; Check the RECV DATA READY bit JE RXIX ; No more data available MOV DX,DATREG[SI] ; UART DATA REGISTER IN AL,DX ; Get data, clear status CMP XON_XOFF[SI],'E' ; FLOW CONTROL ENABLED? JNE RXI2 ; No. Don't check for XON/XOFF ; Check each character for possible flow control (XON/XOFF) AND AL,7FH ; STRIP PARITY CMP AL,CONTROL_S ; STOP COMMAND RECEIVED? JNE RXI1 ; Jump if not. Might be ^Q though. MOV PC_OFF[SI],1 ; Stop output JMP SHORT RXI0 ; Don't store character RXI1: CMP AL,CONTROL_Q ; GO COMMAND RECEIVED? JNE RXI2 ; No. Not a flow control character MOV PC_OFF[SI],0 ; Enable output JMP SHORT RXI0 ; Don't store character ; Have a real data byte. Store if possible. RXI2: CMP SIZE_RDATA[SI],R_SIZE ; SEE IF ANY ROOM JL RXI6 ; CONTINUE IF SO INC WORD PTR EOVFLOW[SI] ; BUMP OVERFLOW ERROR COUNT JMP SHORT RXIX RXI6: MOV BX,END_RDATA[SI] ; BX POINTS TO FREE SPACE MOV RDATA[SI][BX],AL ; MOVE DATA TO BUFFER INC SIZE_RDATA[SI] ; GOT ONE MORE CHARACTER INC BX ; INCREMENT END_RDATA POINTER AND BX,R_SIZE-1 ; Ring the pointer MOV END_RDATA[SI],BX ; SAVE VALUE ; See if we must tell remote host to stop outputting. CMP XON_XOFF[SI],'E' ; FLOW CONTROL ENABLED? JNE RXIX ; No CMP HOST_OFF[SI],1 ; Already told remote to shut up? JE RXIX ; Yes. Don't flood him with ^Ss CMP SIZE_RDATA[SI],R_SIZE/2 ; RECEIVE BUFFER NEARLY FULL? JLE RXIX ; No. No need to stifle remote end ; Would like to wait here for URGENT_SEND to go off if it is on. ; But we need to take a TX interrupt for that to happen. MOV AL,CONTROL_S ; TURN OFF HOST IF SO CALL SENDII ; SEND IMMEDIATELY INTERNAL MOV HOST_OFF[SI],1 ; HOST IS NOW OFF RXIX: JMP REPOLL INT_HNDLR4 ENDP INT_HNDLR3 ENDP INT_HNDLR2 ENDP INT_HNDLR1 ENDP COM_TEXT ENDS END