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Assembly Source File | 1993-11-20 | 53.2 KB | 1,694 lines

TITLE COMM PAGE 83,132 ; $Id: comm.asm 1.10 1993/11/20 14:51:47 ahd Exp $ ; ; $Log: comm.asm $ ;; Revision 1.10 1993/11/20 14:51:47 ahd ;; Up UUPC/extended buffer size to 16K from 8K ;; ;; Revision 1.9 1993/10/12 00:04:16 ahd ;; rhg changes for 8250 and RTS flow control ;; ;; Revision 1.7 1993/05/31 01:39:23 ahd ;; Add return to spin loop (fix by Bill Plummer) ;; Drop FIFO size to 8 ;; ;; Revision 1.4 1993/05/30 00:20:02 ahd ;; Insert minor delay to allow slow modems to catch up ;; ;; Revision 1.2 1992/12/18 12:08:25 ahd ;; Add Plummer's fix for bad TASM assemble of com_errors ;; ; ; 9-Oct-93 Gumpertz Further improved RTI and made it exit via LSI2 when ; it still has the LSR available for counting errors. ; Added/removed some JMP $+2 instructions to get some ; I/O delay for slow 8259 and UART (8250) chips in ; some old machines; I think one JMP is plenty for an ; 80286; the 386 and 486 are unlikely to be found in ; machines that use old chips like the 8250. Moby Sigh. ; I suppose I will need some volunteers to test it. ; Simplified CHROUT and then expanded it inline and ; deleted the subroutine. Simplified SENDII. ; 8-Oct-93 Gumpertz Added _rts_off and _rts_on to support hardware ; handshaking with modems. ; Changed RXI to read one character without testing LSR. ; 7-Oct-93 Gumpertz Made a number of changes to improve execution speed: ; Changed START_TDATA, END_TDATA, START_RDATA, END_RDATA ; to DWORDS. Deleted TBuff and RBuff; (START_TDATA+2):0 ; and (START_RDATA+2):0 are now used instead. ; Rearranged SPTAB for word alignment. ; Changed SEND_OK to not be 0/1 but 0/10H/20H/30H ; Deleted BP saving, setting, and restoring in routines ; that don't use BP. ; Added checks for R_SIZE or S_SIZE not powers of 2. ; Changed receive_com and sen_com to NOT use CLI ; unless really needed. ; Expanded TX_CHR inline and deleted the subroutine. ; Changed transmit FIFO back to 16 bytes and added ; IER_SHADOW to save reading the IER. ; Added a few even pseudo-ops togain a bit of speed. ; 28-Jun-93 Gumpertz Added COM3IRQ5 option (and a few minor cleanups) ; 14-Jun-93 plummer Add RET to spinloop routine ; 14-Jun-93 plummer Set FIFO thresholds to 8 rather than 16 bytes ; 18-May-93 plummer Define IO$DELAY and use in UART type determination ; 16-May-93 plummer Debug code to printout UART type ; 22-Apr-93 plummer Make case consistent in "TBuff" so it links properly ; 2-Dec-92 plummer Fix com_errors() again. Change got lost. ; Fix com_errors() to avoid problems with tasm. Plummer, 11/16/92 ; 8259 EOI issued after interrupts serviced. Plummer, 3/25/92 ; Fix botch in Set_Baud. Plummer, 3/20/92 ; Put in Gordon Lee's cure from dropped interrupts. Plummer, 3/19/92 ; TEMPORARY ioctl_com(). Plummer, 3/9/92. ; Clear OUT2 bit in UART. Some machines use it so enable IRQ. Plummer, 3/9/92 ; Release send buffer if we can't assign a recv buffer. Plummer, 3/9/92 ; Move EQU's outside of SP_TAB struc definition. ahd, 3/8/92. ; ahd changes: short jmp's out of range in INST, OPEN ??? (ahd, 3/?/92) ; open_com() leaves DTR unchanged so Drew's autobaud works. Plummer, 3/2/92 ; Missing DX load in close_com() -- FIFO mode not cleared. Plummer, 3/2/92 ; C calling convention does not require saving AX, BX, CX, DX. Plummer 2/23/92 ; Flush consideration of the PC Jr. Wm. W. Plummer, 2/15/92 ; Cleanup PUSHF/POPF and CLI/STI usage. Wm. W. Plummer, 2/15/92 ; Make SENDII have Giles Todd's change. Wm. W. Plummer, 2/15/92 ; Changes to Giles Todd's code to support dynamic buffers. Plummer, 2/3/92 ; 26 Jan 92 Giles Todd Prime THR for UARTs which do not give a Tx empty ; interrupt when Tx interrupts are enabled. ; S_SIZE & R_SIZE may be set with -D to MASM. Wm. W. Plummer, 1/19/92 ; Assign buffers dynamically. Wm. W. Plummer, 1/19/92 ; Unfix byte length -- I screwed up. Wm. W. Plummer, 1/15/92 ; Fix byte length with specific PARITY select. Wm. W. Plummer, 1/13/92 ; Buffers up to 4096 per AHD. Wm. W. Plummer, 1/1/92 ; Always use FIFO length of 16 on send side. Wm. W. Plummer, 12/30/91. ; Init DSR and CTS previous state from current status. Wm. Plummer, 12/30/91. ; UUPC conditional to disable v.24. Wm. W. Plummer, 12/30/91. ; Buffer sizes up to 2048 per ahd. Wm. W. Plummer, 12/15/91. ; dtr_on() switches to D connection if CTS&DSR don't come up. WWP, 12/15/91. ; New dtr_on() logic. Wm. W. Plummer, 12/11/91 ; Fix bad reg. per report from user. Wm. W. Plummer, 12/11/91 ; Semicolon before control-L's for MASM 5.00 per ahd. Wm. W. Plummer, 12/8/91 ; 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 TXI. 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 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 ; o Built in XON/XOFF flow control option ; o C language calling conventions ; o Logs all comm errors ; o Direct connect or modem protocol PAGE; ; ; Buffer sizes -- *** MUST be powers of 2 **** IFDEF UUPC R_SIZE EQU 8192 ; 7 1K data packets + header S_SIZE EQU 8192 ; 7 1K data packets + header ENDIF ; If not set above, maybe on assembler command line. But if not, ... IFNDEF R_SIZE R_SIZE EQU 512 ; Recv buffer size ENDIF IFNDEF S_SIZE S_SIZE EQU 512 ; Send buffer size ENDIF IF (R_SIZE AND -R_SIZE) NE R_SIZE .ERR R_SIZE must be a power of 2 ENDIF IF (S_SIZE AND -S_SIZE) NE S_SIZE .ERR S_SIZE must be a power of 2 ENDIF ; INTERRUPTS VECIRQ3 EQU 08H+3 ; IRQ3 VECTOR FROM 8259 VECIRQ4 EQU 08H+4 ; IRQ4 VECTOR FROM 8259 VECIRQ5 EQU 08H+5 ; IRQ5 VECTOR FROM 8259 IRQ3 EQU 2*2*2 ; 8259A OCW1 MASK, M3=1, A0=0 IRQ4 EQU 2*2*2*2 ; 8259A OCW1 MASK, M4=1, A0=0 IRQ5 EQU 2*2*2*2*2 ; 8259A OCW1 MASK, M4=1, A0=0 NIRQ3 EQU NOT IRQ3 AND 0FFH ; COMPLEMENT OF ABOVE NIRQ4 EQU NOT IRQ4 AND 0FFH ; COMPLEMENT OF ABOVE NIRQ5 EQU NOT IRQ5 AND 0FFH ; COMPLEMENT OF ABOVE EOI3 EQU 3 OR 01100000B ; 8259A OCW2 SPECIFIC IRQ3 EOI, A0=0 EOI4 EQU 4 OR 01100000B ; 8259A OCW2 SPECIFIC IRQ4 EOI, A0=0 EOI5 EQU 5 OR 01100000B ; 8259A OCW2 SPECIFIC IRQ5 EOI, A0=0 ; 8259 PORTS INTA00 EQU 20H ; 8259A PORT, A0 = 0 INTA01 EQU 21H ; 8259A PORT, A0 = 1 ; FLOW CONTROL CHARACTERS CONTROL_Q EQU 11H ; XON CONTROL_S EQU 13H ; XOFF ; MISC. DOS EQU 21H ; DOS FUNCTION CALLS ; ; ROM BIOS Data Area ; RBDA SEGMENT AT 40H RS232_BASE DW 4 DUP(?) ; ADDRESSES OF RS232 ADAPTERS RBDA ENDS PAGE; ; ; TABLE FOR EACH SERIAL PORT ; SP_TAB STRUC PORT DB ? ; 1 OR 2 OR 3 OR 4 INSTALLED DB ? ; IS PORT INSTALLED ON THIS PC? (1=YES,0=NO) ; PARAMETERS FOR THIS INTERRUPT LEVEL IRQVEC 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 DD ? ; OLD HANDLER'S OFFSET AND SEGMENT ; ATTRIBUTES BAUD_RATE DW ? ; 19200 MAX (maybe 38400 or 57600 with 16550?) 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) UART_SILO_LEN DB ? ; Size of a transmit silo chunk (1 for 8250) ; 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 bits, masked from MSR IER_SHADOW DB ? ; shadow copy of what we last wrote to IER ; 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 ; ; BUFFER POINTERS START_TDATA DD ? ; POINTER TO FIRST CHARACTER IN X-MIT BUFFER END_TDATA DD ? ; POINTER TO FIRST FREE SPACE IN X-MIT BUFFER START_RDATA DD ? ; POINTER TO FIRST CHARACTER IN REC. BUFFER END_RDATA DD ? ; POINTER 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 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 ; ; Equates having to do with the FIFO ; 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_1 EQU 000H ; RCV Warning level is 1 byte in the FIFO FIFO_SZ_4 EQU 040H ; RCV Warning level is 4 bytes in the FIFO FIFO_SZ_8 EQU 080H ; RCV Warning level is 8 bytes in the FIFO FIFO_SZ_14 EQU 0C0H ; RCV Warning level is 14 bytes in the FIFO ; ; 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_8 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 transmit FIFO in a 16550A PAGE; ; put the data in the DGROUP segment ; far calls enter with DS pointing to DGROUP ; DGROUP GROUP _DATA _DATA SEGMENT PUBLIC 'DATA' ; ; DATA AREAS FOR EACH PORT AREA1 SP_TAB <1,0,VECIRQ4,IRQ4,NIRQ4,EOI4,OFFSET COM_TEXT:INT_HNDLR1> ; COM1 AREA2 SP_TAB <2,0,VECIRQ3,IRQ3,NIRQ3,EOI3,OFFSET COM_TEXT:INT_HNDLR2> ; COM2 IFDEF COM3IRQ5 ; special KLUDGE: assemble for COM3 with IRQ5 instead of IRQ4 AREA3 SP_TAB <3,0,VECIRQ5,IRQ5,NIRQ5,EOI5,OFFSET COM_TEXT:INT_HNDLR3> ; COM3 ELSE ; normal: assemble for COM3 with IRQ4 AREA3 SP_TAB <3,0,VECIRQ4,IRQ4,NIRQ4,EOI4,OFFSET COM_TEXT:INT_HNDLR3> ; COM3 ENDIF AREA4 SP_TAB <4,0,VECIRQ3,IRQ3,NIRQ3,EOI3,OFFSET COM_TEXT:INT_HNDLR4> ; COM4 CURRENT_AREA DW OFFSET DGROUP:AREA1 ; CURRENTLY SELECTED AREA DIV50 DW 2304 ; ACTUAL DIVISOR FOR 50 BAUD IN USE IFDEF DEBUG ST8250 DB "8250 or 16450$" ST16550 DB "16550AN$" STUART DB " UART detected", 0DH, 0AH, '$' ENDIF _DATA ENDS COM_TEXT SEGMENT PARA PUBLIC 'CODE' ASSUME CS:COM_TEXT,DS:DGROUP,ES:NOTHING PUBLIC AREA1, AREA2, AREA3, AREA4 PUBLIC _select_port PUBLIC _save_com PUBLIC _install_com PUBLIC _restore_com PUBLIC _open_com PUBLIC _ioctl_com PUBLIC _close_com PUBLIC _dtr_on PUBLIC _dtr_off PUBLIC _rts_off PUBLIC _rts_on PUBLIC _r_count PUBLIC _s_count PUBLIC _receive_com PUBLIC _send_com PUBLIC _sendi_com IFNDEF UUPC PUBLIC _send_local ENDIF PUBLIC _break_com PUBLIC _com_errors PUBLIC _modem_status IFDEF DEBUG PUBLIC INST2, INST4 PUBLIC OPEN1, OPEN2, OPENX PUBLIC DTRON1, DTRON6, DTRONF, DTRDIR, DTRONS, DTRONX PUBLIC RECV1, RECV3, RECV4, RECVX PUBLIC SEND1, SEND2, SEND3, SENDX PUBLIC WaitN, WaitN1, WaitN2 PUBLIC SENDII, SENDII1, SENDII2, SENDII4 PUBLIC SPINLOOP PUBLIC BREAKX PUBLIC INT_HNDLR1, INT_HNDLR2, INT_HNDLR3, INT_HNDLR4 PUBLIC INT_COMMON, REPOLL, INT_END PUBLIC LSI, LSI2 PUBLIC MSI PUBLIC TXI, TXI1, TXI3, TXI4, TXI9 PUBLIC RXI, RXI0, RXINXT, RXIFUL, RXI1, RXI2, RXI3 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. COMMFIFO.ASM forces the connection to be a D type and lets ; UUPC storm 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 SYSTEMS file 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 PAGE; ; ; void far select_port(int) ; Arg is 1..4 and specifies which COM port is referenced by ; all other calls in this package. ; _select_port PROC FAR push bp mov bp,sp MOV AX,[BP+6] ; get argument CMP AX,1 ; Port 1? JE SP1 ; Yes CMP AX,2 ; Port 2? MOV BX,OFFSET DGROUP:AREA2 ; SELECT COM2 DATA AREA JE SPX ; Yes CMP AX,3 ; Port 3? MOV BX,OFFSET DGROUP:AREA3 ; SELECT COM3 DATA AREA JE SPX ; Yes CMP AX,4 ; Port 4? MOV BX,OFFSET DGROUP:AREA4 ; SELECT COM4 DATA AREA JE SPX ; Yes INT 20H ; N.O.T.A. ????? Halt for debugging! ; Assume port 1 if continued SP1: MOV BX,OFFSET DGROUP:AREA1 ; SELECT COM1 DATA AREA SPX: MOV CURRENT_AREA,BX ; SET SELECTION IN MEMORY mov sp,bp pop bp RET _select_port ENDP PAGE; ; ; void far save_com(void) ; Save the interrupt vector of the selected COM port. ; N.B. save_com() and restore_com() call MUST be properly nested ; _save_com PROC FAR PUSH SI PUSH ES ; SAVE EXTRA SEGMENT MOV SI,CURRENT_AREA ; SI POINTS TO DATA AREA ; Save old interrupt vector MOV AH,35H ; FETCH INTERRUPT VECTOR CONTENTS MOV AL,IRQVEC[SI] ; INTERRUPT NUMBER INT DOS ; DOS 2 FUNCTION MOV WORD PTR OLD_COM[SI],BX ; SAVE ES:BX MOV WORD PTR OLD_COM[SI+2],ES ; FOR LATER RESTORATION POP ES ; RESTORE ES POP SI RET ; DONE _save_com ENDP PAGE; ; ; int far install_com(void) ; ; Install the selected COM port. ; Returns: 0: Failure ; 1: Success ; ; SET UART PORTS FROM RS-232 BASE IN ROM BIOS DATA AREA ; INITIALIZE PORT CONSTANTS AND ERROR COUNTS ; ; Assign blocks of memory for transmit and receive buffers ; _install_com PROC FAR PUSH SI PUSH ES MOV SI,CURRENT_AREA ; SI POINTS TO DATA AREA CMP INSTALLED[SI],1 ; Is port installed on this machine? JNE INST1 ; NO, CONTINUE JMP INST9 ; ELSE JUMP IF ALREADY INSTALLED ; Assign memory for transmit and receive buffers INST1: MOV BX,S_SIZE/16 ; Send buffer size in paragraphs MOV AX,4800H ; Allocate memory INT DOS JC INSTFAIL ; Give fail return MOV WORD PTR START_TDATA[SI],0 MOV WORD PTR START_TDATA[SI+2],AX MOV WORD PTR END_TDATA[SI],0 MOV WORD PTR END_TDATA[SI+2],AX MOV BX,R_SIZE/16 ; Receive buffer size in paragraphs MOV AX,4800H ; Allocate memory INT DOS JC INSTFREET ; jump on FAILURE MOV WORD PTR START_RDATA[SI],0 MOV WORD PTR START_RDATA[SI+2],AX MOV WORD PTR END_RDATA[SI],0 MOV WORD PTR END_RDATA[SI+2],AX IFDEF DEBUG PUSH DI CLD ; Go up in memory XOR AX,AX ; A zero to store MOV ES,START_TDATA[SI] ; Transmit buffer location MOV DI,AX MOV CX,S_SIZE/2 ; Size of buffer REP STOSW ; Clear entire buffer MOV ES,START_RDATA[SI] ; Receive buffer location MOV DI,AX MOV CX,R_SIZE/2 ; Size of buffer REP STOSW ; Clear entire buffer POP DI ENDIF PAGE; 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) ; We interrupt this program to bring you code that we want to be within ; short-jump range of the code that conditionally jumps to it: INSTFREEBOTH: ; Unhand the receive and send buffers assigned above MOV ES,WORD PTR START_RDATA[SI+2] ; Receive buffer paragraph assume ES:nothing MOV AX,4900H ; Release memory INT DOS ; Ignore error INSTFREET: ; Unhand the send buffer assigned above MOV ES,WORD PTR START_TDATA[SI+2] ; Transmit buffer paragraph MOV AX,4900H ; Release memory INT DOS ; Ignore error ; Fall into INSTFAIL ; PORT NOT INSTALLED INSTFAIL: XOR AX,AX JMP INSTX ASSUME ES:RBDA ; And now back to your regularly scheduled program: 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 INSTFREEBOTH ; 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 ; CLEAR ERROR COUNTS 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 PUSHF ; Save caller's interrupt state CLI ; Stray interrupts cause havoc MOV DX,FCR[SI] ; Get FIFO Control Register MOV AL,FIFO_INIT OUT DX,AL ; Try to initialize the FIFO CALL SPINLOOP ; Permit I/O bus to settle MOV DX,IIR[SI] ; Get interrupt ID register IN AL,DX ; See how the UART responded AND AL,FIFO_ENABLED ; Keep only these bits MOV CL,1 ; Assume size 1 for 8250/16450 case CMP AL,FIFO_ENABLED ; See if 16550A JNE INST4 ; Jump if not MOV CL,FIFO_LEN INST4: MOV UART_SILO_LEN[SI],CL ; Save chunk size for XMIT side IF FCR NE IIR ; FCR should be same as IIR MOV DX,FCR[SI] ENDIF MOV AL,FIFO_CLEAR ; disable the FIFOs until open_com OUT DX,AL POPF ; Restore caller's interrupt state MOV AH,25H ; SET INTERRUPT VECTOR CONTENTS MOV AL,IRQVEC[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 ;Fall into INSTX ; Common exit INSTX: MOV INSTALLED[SI],AL ; Indicate whether installed or not IFDEF DEBUG MOV DX,OFFSET ST8250 CMP UART_SILO_LEN[SI],1 JE INSTXX MOV DX,OFFSET ST16550 INSTXX: MOV AH,9 INT DOS ; Announce UART type MOV DX,OFFSET STUART INT DOS ENDIF POP ES assume ES:nothing POP SI RET _install_com ENDP PAGE; ; ; void far restore_com(void) ; Restore original interrupt vector and release storage ; _restore_com PROC FAR PUSHF PUSH SI PUSH ES MOV SI,CURRENT_AREA ; SI POINTS TO DATA AREA CLI MOV INSTALLED[SI],0 ; PORT IS NO LONGER INSTALLED PUSH DS ; SAVE DS LDS DX,OLD_COM[SI] ; OLD INTERRUPT HANDLER IN DS:BX MOV AH,25H ; SET INTERRUPT VECTOR FUNCTION MOV AL,IRQVEC[SI] ; INTERRUPT NUMBER INT DOS ; DOS FUNCTION POP DS ; Recover our data segment MOV ES,WORD PTR START_TDATA[SI+2] ; Transmit buffer paragraph MOV AX,4900H ; Release memory INT DOS ; Ignore error MOV ES,WORD PTR START_RDATA[SI+2] ; Receive buffer paragraph MOV AX,4900H INT DOS ; Ignore error POP ES POP SI POPF RET _restore_com ENDP PAGE; ; ; void far open_com(int Baud, char Conn, char Parity, char Stops, char Flow); ; ; 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 MOV SI,CURRENT_AREA ; SI POINTS TO DATA AREA CLI ; INTERRUPTS OFF TEST INSTALLED[SI],1 ; Port installed? JNZ OPEN1 ; Yes --> Proceed JMP OPENX ; No --> Get out OPEN1: 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 (high priority) flow ctl MOV SEND_OK[SI],0 ; DTR&CTS are not on yet ; RESET BUFFER COUNTS AND POINTERS MOV WORD PTR START_TDATA[SI],0 MOV WORD PTR END_TDATA[SI],0 MOV WORD PTR START_RDATA[SI],0 MOV WORD PTR END_RDATA[SI],0 MOV SIZE_TDATA[SI],0 MOV SIZE_RDATA[SI],0 ; ; RESET THE UART MOV DX,MCR[SI] ; Modem Control Register IN AL,DX ; Get current settings JMP SHORT $+2 ; In next line, comment doesn't match the constant. Should it be 01H? -RHG AND AL,0FEH ; Clr RTS, OUT1, OUT2 & LOOPBACK, but OUT DX,AL ; Not DTR (No hangup during autobaud) MOV DX,MSR[SI] ; Modem Status Register JMP SHORT $+2 IN AL,DX ; Get current DSR and CTS states. JMP SHORT $+2 AND AL,30H ; Init PREVIOUS STATE FLOPS to current OUT DX,AL ; state and clear Loopback, etc. MOV SEND_OK[SI],AL ; If 30H, allow TXI to send out data JMP SHORT $+2 IN AL,DX ; Re-read to get delta bits & clr int JMP SHORT $+2 OPEN2: 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 JMP SHORT $+2 IN AL,DX MOV DX,DATREG[SI] ; RESET RECEIVE DATA CONDITION JMP SHORT $+2 IN AL,DX MOV DX,MSR[SI] ; RESET MODEM DELTAS AND CONDITIONS JMP SHORT $+2 IN AL,DX CALL Set_Baud ; Set the baud rate from arg PAGE; ; SET PARITY AND NUMBER OF STOP BITS MOV AL,03H ; Default: NO PARITY + 8 bits data CMP PARITY[SI],'O' ; ODD PARITY REQUESTED? JNE P1 ; JUMP IF NOT MOV AL,0AH ; SELECT ODD PARITY + 7 bits data JMP SHORT P4 ; CONTINUE ; P1: CMP PARITY[SI],'E' ; EVEN PARITY REQUESTED? JNE P2 ; JUMP IF NOT MOV AL,1AH ; SELECT EVEN PARITY + 7 bits data JMP SHORT P4 ; CONTINUE ; P2: CMP PARITY[SI],'M' ; MARK PARITY REQUESTED? JNE P3 ; JUMP IF NOT MOV AL,2AH ; SELECT MARK PARITY + 7 bits data JMP SHORT P4 P3: CMP PARITY[SI],'S' ; SPACE parity requested? JNE P4 ; No. Must be 'N' (NONE) MOV AL,3AH ; Select SPACE PARITY + 7 bits data P4: 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 CMP UART_SILO_LEN[SI],1 ; Is it a 16550A? JE P5 ; jump if 8250, 16450, or 16550(no A) MOV DX,FCR[SI] ; I/O Address of FIFO control register MOV AL,FIFO_INIT ; Clear FIFOs, set size, enable FIFOs OUT DX,AL JMP SHORT $+2 ; ENABLE INTERRUPTS ON 8259 AND UART P5: IN AL,INTA01 ; SET ENABLE BIT ON 8259 AND AL,NIRQ[SI] JMP SHORT $+2 OUT INTA01,AL MOV DX,IER[SI] ; Interrupt enable register MOV AL,0DH ; Line & Modem status, recv [GT] OUT DX,AL ; Enable those interrupts MOV IER_SHADOW[SI],AL OPENX: POPF ; Restore interrupt state POP SI mov sp,bp pop bp RET ; DONE _open_com ENDP PAGE; ; ; void far ioctl_com(int Flags, int Arg1, ...) ; Flags have bits saying what to do or change (IGNORED TODAY) ; Arg1, ... are the new values ; _ioctl_com PROC FAR PUSH BP MOV BP,SP PUSH SI MOV SI,CURRENT_AREA ; Pointer to COMi private area TEST INSTALLED[SI],1 JE IOCTLX ; No good. Just return. PUSHF ; Save interrupt context CLI ; Prevent surprises ; MOV AX,[BP+6] ; Flags ; Check bits here... MOV AX,[BP+8] ; Line speed MOV BAUD_RATE[SI],AX ; Save in parameter block CALL Set_Baud ; Set the baud rate in UART POPF ; Restore interrupt state IOCTLX: POP SI MOV SP,BP POP BP RET _ioctl_com ENDP PAGE; ; ioctl-called routines (internal) ... ; SI: COMi private block ; CALL Set_Baud ; Returns: (nothing) ; Clobber: AX, BX, DX Set_Baud PROC NEAR MOV AX,50 MUL DIV50 ; Could be different on a PCJr! DIV BAUD_RATE[SI] ; Get right number for the UART MOV BX,AX ; Save it MOV DX,LCR[SI] ; Line Control Register IN AL,DX ; Get current size, stops, parity,... MOV AH,AL OR AL,80H ; DLAB bit JMP SHORT $+2 OUT DX,AL ; Talk to the baud rate regs now MOV DX,WORD PTR DLL[SI] ; Least significant byte MOV AL,BL ; New value JMP SHORT $+2 OUT DX,AL ; To UART MOV DX,WORD PTR DLH[SI] ; Most significant byte MOV AL,BH ; New value JMP SHORT $+2 OUT DX,AL MOV DX,LCR[SI] ; Line Control Register MOV AL,AH JMP SHORT $+2 OUT DX,AL ; Turn off DLAB, keep saved settings RET Set_Baud ENDP PAGE; ; ; void far close_com(void) ; Turn off interrupts from the COM port ; _close_com PROC FAR PUSH SI PUSHF 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 CLI MOV DX,IER[SI] XOR AL,AL OUT DX,AL ; No interrupts right now, please MOV IER_SHADOW[SI],AL MOV DX,FCR[SI] ; FIFO Control Register MOV AL,FIFO_CLEAR ; Disable FIFOs JMP SHORT $+2 OUT DX,AL MOV DX,MCR[SI] ; Modem control register XOR AL,AL ; OUT2 is IRQ enable on some machines, JMP SHORT $+2 OUT DX,AL ; So, clear RTS, OUT1, OUT2, LOOPBACK ; TURN OFF 8259 MOV DX,INTA01 JMP SHORT $+2 IN AL,DX OR AL,IRQ[SI] JMP SHORT $+2 OUT DX,AL CCX: POPF ; Restore interrupt state POP SI RET _close_com ENDP PAGE; ; ; void far dtr_off(void) ; Tells modem we are done. Remote end should hang up also. ; _dtr_off PROC FAR 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 IFNDEF UUPC IN AL,DX ; Get current state SHR AL,1 ; Save old DTR bit in Carry flag JMP SHORT $+2 ENDIF MOV AL,08H ; DTR off, RTS off, OUT2 on OUT DX,AL IFNDEF UUPC JNC DFX ; if DTR wasn't on then don't wait. MOV AX,50 ; 50/100 of second CALL WaitN ; V.24 says it must be low >1/2 sec ENDIF DFX: POP SI RET _dtr_off ENDP PAGE; ; ; void far dtr_on(void) Tell modem we can take traffic ; _dtr_on PROC FAR 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 CMP CONNECTION[SI],'D' ; Direct connection (no DSR,CTS)? JE DTRDIR ; if so, then don't wait ; 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,06 ; Allow a few seconds CMP BH,60 ; Wrap around check JL DTRON1 ; No wrap SUB BH,60 DTRON1: CMP SEND_OK[SI],30H ; 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 ; 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 PAGE; ; Failure return DTRONF: MOV CONNECTION[SI],'D' ; Switch to DIR connection (MSTATINT) ; Fall into DTRDIR DTRDIR: MOV SEND_OK[SI],30H ; Make believe DSR & CTS are up!!! ; Fall into DTRONS ; Successful return DTRONS: ; SEND_OK is on. Setting it again could confuse interrupt level ; Fall into DTRONX DTRONX: IFNDEF UUPC MOV AX,200H ; 2 Seconds CALL WaitN ; V.24 says 2 sec hi before data ENDIF POP SI RET _dtr_on ENDP PAGE; ; ; void far rts_off(void) ; Turns off RTS for RTS-style throttling of modem->PC data ; _rts_off PROC FAR PUSH SI MOV SI,CURRENT_AREA ; SI POINTS TO DATA AREA TEST INSTALLED[SI],1 ; PORT INSTALLED? JZ RFX ; ABORT IF NOT MOV DX,MCR[SI] ; Modem Control Register MOV AL,00001001B ; OUT 2, DTR OUT DX,AL RFX: POP SI RET _rts_off ENDP PAGE; ; ; void far rts_off(void) ; Turns on RTS for RTS-style throttling of modem->PC data ; _rts_on PROC FAR PUSH SI MOV SI,CURRENT_AREA ; SI POINTS TO DATA AREA TEST INSTALLED[SI],1 ; PORT INSTALLED? JZ RNX ; ABORT IF NOT MOV DX,MCR[SI] ; Modem Control Register MOV AL,00001011B ; OUT 2, RTS, DTR OUT DX,AL RNX: POP SI RET _rts_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 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 RET WaitN ENDP PAGE; ; ; unsigned long r_count(void) ; Value is really two uints: Buffer size in high half, count in low. ; Count returned is <= number of chars waiting to be read. ; (More may come in after you asked.) ; _r_count PROC FAR PUSH SI MOV SI,CURRENT_AREA ; SI POINTS TO DATA AREA XOR AX,AX ; Say nothing available if not inst'd MOV DX,R_SIZE ; Size of entire receive buffer TEST INSTALLED[SI],1 ; PORT INSTALLED? JZ RCX ; ABORT IF NOT MOV AX,SIZE_RDATA[SI] ; GET NUMBER OF BYTES USED RCX: POP SI RET _r_count ENDP PAGE; ; ; char far receive_com(void) ; Returns AX: -1 if port not installed or no characters available ; or AX: the next character with parity stipped if not in P mode ; _receive_com PROC FAR PUSH SI PUSH ES MOV SI,CURRENT_AREA ; SI POINTS TO DATA AREA mov ax,-1 ; -1 if bad call TEST INSTALLED[SI],1 ; PORT INSTALLED? JZ RECVX ; ABORT IF NOT CMP SIZE_RDATA[SI],0 ; ANY CHARACTERS? JE RECVX ; Return -1 in AX mov ah,0 ; good call LES BX,START_RDATA[SI] ; GET POINTER TO OLDEST CHAR MOV AL,ES:[BX] ; Get character from buffer INC BX ; BUMP START_RDATA AND BX,R_SIZE-1 ; Ring the pointer MOV WORD PTR START_RDATA[SI],BX ; SAVE THE NEW START_RDATA VALUE DEC SIZE_RDATA[SI] ; ONE LESS CHARACTER CMP PARITY[SI],'N' ; ARE WE RUNNING WITH NO PARITY? LBA JE RECV1 ; IF SO, DON'T STRIP HIGH BIT LBA AND AL,7FH ; STRIP PARITY BIT RECV1: CMP XON_XOFF[SI],'E' ; XON/XOFF FLOW CONTROL ENABLED? JNE RECVX ; DO NOTHING IF DISABLED CMP HOST_OFF[SI],1 ; HOST TURNED OFF? JNE RECVX ; JUMP IF NOT CMP SIZE_RDATA[SI],R_SIZE/16; RECEIVE BUFFER NEARLY EMPTY? JAE RECVX ; 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 PUSHF ; Save interrupt context RECV3: CLI ; TURN OFF INTERRUPTS CMP URGENT_SEND[SI],1 ; Previous send still in progress? JNE RECV4 ; No. There is space now. STI ; Yes. Wait for interrupt to take it. JMP SHORT $+2 ; Waste some time with interrupts on JMP SHORT RECV3 ; Loop 'til it's gone RECV4: CALL SENDII ; SEND IMMEDIATELY INTERNAL POPF ; Restore interrupt state POP AX ; RESTORE RECEIVED CHAR RECVX: POP ES POP SI RET _receive_com ENDP PAGE; ; ; unsigned long s_count(void) ; Value is really two uints: Buffer size in high half (returned in DX). ; Free space count in low (returned in AX). ; Count returned is <= number of chars which can be sent without blocking. ; (More may become available after you asked.) ; ; N.B. The free space might be negative (-1) if the buffer was full and then ; the program called SENDI or RXI required sending a control-S to squelch ; the remote sender. Return 0 in this case. ; _s_count PROC FAR PUSH SI MOV SI,CURRENT_AREA ; SI POINTS TO DATA AREA XOR AX,AX ; NO SPACE LEFT IF NOT INSTALLED TEST INSTALLED[SI],1 ; PORT INSTALLED? JZ SCX ; ABORT IF NOT MOV AX,S_SIZE-1 ; Size, keeping one aside for SENDII SUB AX,SIZE_TDATA[SI] ; Minus number in use right now CWD ; Avoid returning a negative number NOT DX AND AX,DX ; return 0 if it was negative SCX: MOV DX,S_SIZE-1 ; Leave 1 byte for a SENDII call POP SI RET _s_count ENDP PAGE; ; ; void far send_com(char) ; Send a character to the selected port ; _send_com PROC FAR push bp mov bp,sp PUSH SI MOV SI,CURRENT_AREA ; SI POINTS TO DATA AREA TEST INSTALLED[SI],1 ; PORT INSTALLED? JZ SENDX ; ABORT IF NOT SEND1: CMP SIZE_TDATA[SI],S_SIZE-1 ; BUFFER FULL? (Leave room for SENDII) JAE SEND1 ; Wait for interrupts to empty buffer MOV AL,[BP+6] ; Character to send PUSH ES LES BX,END_TDATA[SI] ; ES:BX points to free space MOV ES:[BX],AL ; Move character to buffer INC BX ; INCREMENT END_TDATA AND BX,S_SIZE-1 ; Ring the pointer MOV WORD PTR END_TDATA[SI],BX ; SAVE NEW END_TDATA INC SIZE_TDATA[SI] ; ONE MORE CHARACTER IN X-MIT BUFFER TEST PC_OFF[SI],1 ; Were we stopped by a ^S from host? JNZ SEND2 ; Yes. Don't enable interrupts yet. CMP SEND_OK[SI],30H ; See if Data Set Ready & CTS are on JNE SEND2 ; No. Still can't enable TX ints PUSHF ; Save interrupt state CLI TEST IER_SHADOW[SI],02H ; Tx interrupts enabled? JNZ SEND3 ; Jump if so: transmit already running MOV DX,IER[SI] ; Interrupt Enable Register MOV AL,0FH ; Rx, Tx, Line & Modem enable bits OUT DX,AL ; Enable those interrupts MOV IER_SHADOW[SI],AL SEND3: POPF ; Restore interrupt state SEND2: POP ES SENDX: POP SI mov sp,bp pop bp RET _send_com ENDP PAGE; ; ; void far sendi_com(char) ; Send a character immediately by placing it at the head of the queue ; _sendi_com PROC FAR push bp mov bp,sp PUSH SI mov al,[bp+6] MOV SI,CURRENT_AREA ; SI POINTS TO DATA AREA TEST INSTALLED[SI],1 ; PORT INSTALLED? JZ SENDIX ; Return if not PUSHF ; Save interrupt state 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 $+2 ; Waste some time with interrupts on JMP SHORT SENDI3 ; Loop 'til it's gone SENDI4: CALL SENDII ; CALL INTERNAL SEND IMMEDIATE POPF ; Restore interrupt state SENDIX: POP SI mov sp,bp pop bp RET _sendi_com ENDP PAGE; ; SENDII(AL, SI) [internal routine] ; Put char at head of output queue so it will go out next ; Called from process level and (receive) interrupt level ; DEPENDS ON CALLER TO KEEP INTERRUPTS CLEARED AND SET SI ; Clobbers AL ; SENDII PROC NEAR TEST IER_SHADOW[SI],02H ; Tx interrupts enabled? JNZ SENDII1 ; Jump if so: transmit already running CMP SEND_OK[SI],30H ; See if Data Set Ready & CTS are on JNE SENDII1 ; No. Still can't enable TX ints ; Was idle: transmit the character without buffering; enable TX interrupt PUSH DX MOV DX,DATREG[SI] ; I/O address of data register OUT DX,AL ; Output the character MOV DX,IER[SI] ; Interrupt Enable Register MOV AL,0FH ; Rx, Tx, Line & Modem enable bits OUT DX,AL ; Enable those interrupts MOV IER_SHADOW[SI],AL POP DX RET ; Unable to send the character now: buffer it. SENDII1:PUSH BX PUSH ES LES BX,START_TDATA[SI] ; ES:BX point to 1st chr in buffer CMP SIZE_TDATA[SI],S_SIZE ; BUFFER FULL? JB SENDII2 ; JUMP IF NOT INC WORD PTR EOVFLOW[SI] ; BUMP ERROR COUNT (Can this happen?) JMP SHORT SENDII4 ; and overwrite old first char SENDII2:DEC BX ; Back it up AND BX,S_SIZE-1 ; Ring it MOV WORD PTR START_TDATA[SI],BX ; Save new value INC SIZE_TDATA[SI] ; ONE MORE CHARACTER IN X-MIT BUFFER ; No check for PC_OFF here. Flow control ALWAYS gets sent! SENDII4:MOV ES:[BX],AL ; Move character to buffer MOV URGENT_SEND[SI],1 ; Flag high priority message POP ES POP BX RET SENDII ENDP PAGE; ;*---------------------------------------------------------------------* ;* s p i n l o o p * ;* * ;* Waste time to allow slow UART chips to catch up * ;*---------------------------------------------------------------------* SPINLOOP PROC NEAR PUSH CX MOV CX,100 WASTERS: CALL CRET ; Better time waster than a 1-byte NOP LOOP WASTERS POP CX CRET: RET SPINLOOP ENDP PAGE; IFNDEF UUPC ; ; void far send_local(char); ; Simulate a loopback by placing characters sent in recv buffer ; _send_local PROC FAR push bp mov bp,sp PUSH SI MOV SI,CURRENT_AREA ; SI POINTS TO DATA AREA TEST INSTALLED[SI],1 ; PORT INSTALLED? JZ SLX ; ABORT IF NOT PUSHF ; Save interrupt state CLI ; INTERRUPTS OFF CMP SIZE_RDATA[SI],R_SIZE ; SEE IF ANY ROOM JB SL3 ; SKIP IF ROOM INC WORD PTR EOVFLOW[SI] ; BUMP OVERFLOW COUNT JMP SHORT SL9 ; PUNT SL3: PUSH ES LES BX,END_RDATA[SI] ; ES:BX POINTS TO FREE SPACE MOV AL,[BP+6] ; Get the byte to send MOV ES:[BX],AL ; Put into buffer INC BX ; INCREMENT END_RDATA POINTER AND BX,R_SIZE-1 ; Ring the pointer MOV WORD PTR END_RDATA[SI],BX ; SAVE VALUE INC SIZE_RDATA[SI] ; GOT ONE MORE CHARACTER POP ES SL9: POPF ; Restore interrupt state SLX: POP SI mov sp,bp pop bp RET ; DONE _send_local ENDP ENDIF PAGE; ; ; void far break_com(void) Send a BREAK out to alert the remote end ; _break_com PROC FAR PUSH SI 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 OR AL,40H ; TURN ON BREAK BIT JMP SHORT $+2 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 AND AL,NOT 40H ; TURN OFF BREAK BIT JMP SHORT $+2 OUT DX,AL ; RESTORE LINE CONTROL REGISTER BREAKX: POP SI RET _break_com ENDP PAGE; ; ; ERROR_STRUCT far *com_errors(void) ; Returns a pointer to the table of error counters ; _com_errors PROC FAR PUSH SI MOV SI,CURRENT_AREA ; Point to block for selected port LEA AX,ERROR_BLOCK[SI] ; Offset to error counters MOV DX,DS ; Value is in DX:AX POP SI RET _com_errors ENDP ; ; char far modem_status(void) ; Returns the modem status register in AL ; ; Bits are: 0x80: Carrier Detect ; 0x40: Ring Indicator ; 0x20: Data Set Ready ; 0x10: Clear To Send ; 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 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 RET _modem_status ENDP PAGE; ; ; INT_HNDLR1 - HANDLES INTERRUPTS GENERATED BY COM1: ; assume DS:nothing even 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: ; even 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: ; even 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: ; even 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: ; SI has been pushed and loaded PUSH AX PUSH DX PUSH DS PUSH BX PUSH CX PUSH ES MOV AX,DGROUP ; offsets are relative to DGROUP [WWP] MOV DS,AX assume DS:DGROUP ; FIND OUT WHERE INTERRUPT CAME FROM AND JUMP TO ROUTINE TO HANDLE IT REPOLL: MOV DX,IIR[SI] ; Interrupt Identification Register IN AL,DX MOV BL,AL ; Put where we can index by it SHR AL,1 ; Check the "no interrupt present" bit JC INT_END ; ON means we are done AND BX,000EH ; Ignore FIFO_ENABLED bits, etc. JMP WORD PTR CS:INT_DISPATCH[BX]; Go to appropriate routine even INT_DISPATCH: DW MSI ; 0: Modem status interrupt DW TXI ; 2: Transmitter interrupt DW RXI ; 4: Receiver interrupt DW LSI ; 6: Line status interrupt DW INT_END ; 8: (Future use by UART makers) DW INT_END ; A: (Future use by UART makers) DW RXI ; C: FIFO Timeout DW INT_END ; E: (Future use by UART makers) INT_END: ; Now tell 8259 we handled that IRQ MOV DX,IER[SI] ; Gordon Lee's cure for dropped ints XOR AL,AL OUT DX,AL ; Disable UART interrupts MOV AL,EOI[SI] ; End of Interrupt. With input gone, POP ES ; do the POPs now for some I/O delay POP CX OUT INTA00,AL ; Give EOI to 8259 Interrupt ctlr MOV AL,IER_SHADOW[SI] ; Get saved interrupt enable bits POP BX ; do the POPs now for some I/O delay POP DS assume DS:nothing OUT DX,AL ; Restore them, maybe causing a ; transition into the 8259!!! POP DX POP AX POP SI IRET PAGE; ; ; Line status interrupt ; even assume DS:DGROUP LSI: MOV DX,LSR[SI] ; Line status register IN AL,DX ; Read line status & bump error counts SHR AL,1 LSI2: ; RXI also comes here with the LSR (shifted right 1) already in AL SHR AL,1 ; OVERRUN ERROR? ADC WORD PTR EOVRUN[SI],0 ; BUMP ERROR COUNT SHR AL,1 ; PARITY ERROR? ADC WORD PTR EPARITY[SI],0 ; BUMP ERROR COUNT SHR AL,1 ; FRAMING ERROR? ADC WORD PTR EFRAME[SI],0 ; BUMP ERROR COUNT SHR AL,1 ; BREAK RECEIVED? ADC WORD PTR EBREAK[SI],0 ; BUMP ERROR COUNT JMP REPOLL ; SEE IF ANY MORE INTERRUPTS ; ; Modem status interrupt ; even assume DS:DGROUP MSI: MOV DX,MSR[SI] ; Modem Status Register IN AL,DX ; Read status & clear interrupt AND AL,30H ; Expose CTS and Data Set Ready CMP CONNECTION[SI],'D' ; Direct connection - ignore int JNE MSI0 ; if not direct them DSR,CTS valid MOV AL,30H ; Make believe DSR & CTS are up!!! MSI0: 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 MOV IER_SHADOW[SI],AL JMP REPOLL ; Check for other interrupts PAGE; ; ; Receive interrupt ; even assume DS:DGROUP RXI: LES BX,END_RDATA[SI] ; ES:BX points to free space RXI0: MOV DX,DATREG[SI] ; UART DATA REGISTER IN AL,DX ; Get data, clear status CMP XON_XOFF[SI],'E' ; XON/XOFF FLOW CONTROL ENABLED? JE RXI1 ; Yes. Check for XON/XOFF CMP SIZE_RDATA[SI],R_SIZE ; Any room in buffer? JAE RXIFUL ; No room left MOV ES:[BX],AL ; Put character in buffer INC SIZE_RDATA[SI] ; GOT ONE MORE CHARACTER INC BX ; Bump pointer past location just used AND BX,R_SIZE-1 ; Ring the pointer RXINXT: MOV DX,LSR[SI] ; Line Status Register IN AL,DX ; Read it SHR AL,1 ; Check the RECV DATA READY bit JC RXI0 ; More data; go get it MOV WORD PTR END_RDATA[SI],BX ; Store updated pointer JMP SHORT LSI2 ; No more data; count errors if any RXIFUL: INC WORD PTR EOVFLOW[SI] ; BUMP OVERFLOW ERROR COUNT MOV WORD PTR END_RDATA[SI],BX ; Store updated pointer JMP REPOLL ; Check each character for possible flow control (XON/XOFF) RXI1: MOV AH,AL ; Save character in AH AND AL,7FH ; STRIP PARITY CMP AL,CONTROL_S ; STOP COMMAND RECEIVED? JNE RXI2 ; Jump if not. Might be ^Q though. MOV PC_OFF[SI],1 ; Stop output JMP SHORT RXINXT ; Don't store the character RXI2: CMP AL,CONTROL_Q ; GO COMMAND RECEIVED? JNE RXI3 ; No. Not a flow control character MOV PC_OFF[SI],0 ; Enable output JMP SHORT RXINXT ; Don't store the character RXI3: CMP SIZE_RDATA[SI],R_SIZE ; SEE IF ANY ROOM JAE RXIFUL ; No room left MOV ES:[BX],AH ; Put saved character in buffer INC SIZE_RDATA[SI] ; GOT ONE MORE CHARACTER INC BX ; Bump pointer past location just used AND BX,R_SIZE-1 ; Ring the pointer ; See if we must tell remote host to stop outputting. CMP HOST_OFF[SI],1 ; Already told remote to shut up? JE RXINXT ; Yes. Don't flood him with ^Ss CMP SIZE_RDATA[SI],R_SIZE/2 ; RECEIVE BUFFER NEARLY FULL? JBE RXINXT ; 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 JMP RXINXT PAGE; ; ; Transmit interrupt ; even assume DS:DGROUP TXI: CMP SEND_OK[SI],30H ; Hardware (CTS & DSR on) OK? JNE TXI9 ; No. Must wait 'til cable right! MOV CX,1 ; Transfer count for flow ctl CMP URGENT_SEND[SI],CL ; Flow control character to send? JE TXI3 ; Yes. Always send flow control. CMP PC_OFF[SI],CL ; Flow control (XON/XOFF) OK? JE TXI9 ; Stifled & not urgent. Forget it. TXI1: MOV CL,UART_SILO_LEN[SI] ; MAX size chunk (1 for 8250/16450) ; Too bad there is no "Transmitter FIFO Full" indication! CMP SIZE_TDATA[SI],CX ; SEE IF ANY MORE DATA TO SEND JAE TXI3 ; jump if UART is the limit MOV CX,SIZE_TDATA[SI] ; Buffer contents limited. Use that. JCXZ TXI9 ; No data, disable TX ints TXI3: LES BX,START_TDATA[SI] ; ES:BX points to next char to send MOV DX,DATREG[SI] ; I/O address of data register TXI4: MOV AL,ES:[BX] ; Get character from buffer OUT DX,AL ; Output the character INC BX ; Bump the head pointer AND BX,S_SIZE-1 ; Ring it DEC SIZE_TDATA[SI] ; One fewer in buffer now LOOP TXI4 ; Keep going 'til silo is full MOV WORD PTR START_TDATA[SI],BX ; Store pointer back 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 MOV IER_SHADOW[SI],AL JMP REPOLL INT_HNDLR4 ENDP INT_HNDLR3 ENDP INT_HNDLR2 ENDP INT_HNDLR1 ENDP COM_TEXT ENDS END