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Assembly Source File | 1986-06-01 | 40.9 KB | 1,056 lines

30-May-86 01:03:08-PDT,41855;000000000001 Return-Path: <milne@ICSE.UCI.EDU> Received: FROM ICSE.UCI.EDU BY USC-ISIB.ARPA WITH TCP ; 30 May 86 00:57:05 PDT Received: from localhost by ICSE.UCI.EDU id a007132; 29 May 86 22:54 PDT To: info-ibmpc@usc-isib.arpa Subject: ComPackage version for UCSD p-System Date: Thu, 29 May 86 22:54:20 -0800 From: Alastair Milne <milne@ICSE.UCI.EDU> Here is my adaptation of the simpler version of ComPackage for the UCSD p-System. There are 5 or 6 separate source files, mostly because of limitations of the p-System assembler. They are delimited by <<<<< marks. I have placed on each file the documentation header we use at work, to explain it and give its relations to the other files. I hope they will be adequate: this is the first time I've sent them to a non-p-System installation. Several of the names exported to Pascal have been changed (lengthened). This was done to make them clearer, and in particular to avoid confusion with names from other units trying to serve the same purpose. I trust it will not result in too much confusion. The bug fix I reported is in the interrupt service routine, whose file is still called COM.PKG1.TEXT. I hope you will not find restoring this to MASM conventions overly difficult. If questions arise about what I've done, I'll be happy to help. Thank you, Alastair Milne <<<<<<<<<<<<<<<<<<<<<<<<<<< ;{% global equates and macro definitions for ComPackage ;File Name : COM.EQU.TEXT Code Name : <none> ; ;Assembly context. ; Files included : none ; ;%} rsize .equ 2048 ; size of receive buffer tsize .equ 256 ; size of transmit buffer base .equ 3F0H ; base of address of aux. port registers aux_int .equ 0CH ; interrupt number for aux port int_off .equ aux_int*4 ; offset of interrupt vector datreg .equ base + 8H ; data register dll .equ base + 8H ; low divisor latcH dlh .equ base + 9H ; high divisor latch ier .equ base + 9H ; interrupt enable register iir .equ base + 0AH ; interrupt identification register lcr .equ base + 0BH ; line control register mcr .equ base + 0CH ; modem control register lsr .equ base + 0DH ; line status register msr .equ base + 0EH ; modem status register dla .equ 80H ; divisor latch access mode .equ 03H ; 8-bits, no parity dtr .equ 0BH ; bits to set dtr line dtr_of .equ 00H ; turn off dtr, rts, and tHe interupt driver thre .equ 20H ; mask to find status of xmit holding register rxint .equ 01H ; enable data available interrupt txint .equ 02H ; enable tx holding register empty interrupt tcheck .equ 20H ; mask for checking tx reg status on interrupt rcheck .equ 01H ; mask for checking rx reg status on interrupt imr .equ 21H ; interuprt mask register int_mask .equ 0EFH ; mask to clear bit 4 int_pend .equ 01H ; there is an interrupt pending mstat .equ 00H ; modem status interrupt wr .equ 02H ; ready to xmit data rd .equ 04H ; received data interrupt lstat .equ 06H ; line status interrupt ack .equ 244 ; acknowledge symbol parity .equ 7FH ; bits to mask off parity ocw2 .equ 20H ; operational control word on 8259 eoi .equ 64H ; specific end of interrupt 4 brkbit .equ 40H ; bits to cause break true .equ 1 ; truth false .equ 0 ; falsehood XOn .equ 17 ; ASCII Transmit On code, for XOn/XOff protocl XOff .equ 19 ; ASCII Transmit Off code, " " " ; assumes the parameter is the first word of an IP:CS pair, ; places the current CS into the CS half, and does an ; indirect long call to the routine pointed to. ; NOTE: destroys bx .macro CallRel lea bx, cs:%1 mov cs:(bx+2), cs calll cs:(%1) .endm <<<<<<<<<<<<<<<<<<<<<<<<<<< .title "COM.PKG" ;{% interrupt handler, installer, and remover for ComPackage ;File Name : COM.PKG1.TEXT Code Name : COM.PKG1.CODE ; ;History: ; (Adapted from code for MS-Pascal by John Romkey and Jerry Saltzer of MIT ; by Richard Gillmann (GILLMANN@ISIB), 1983. Taken from COM_PKG1.ASM ; from the INFO-IBMPC repository at the University of Southern California.) ;Date Coder Modification ; winter, 1986 Alastair Milne Adapted to p-System assembler syntax, ; and p-System calling conventions. ; - clearing of serial port (i.e. forced break) ; moved from init. of interrupt handler ; to user-callable routine. ; - XOn/XOff protocol (input & output) added to ; intrpt handler. ; - bug fix: transmit-ready interrupt is raised ; before transmit shift register is ready. ; Caused strings to be sent as garbage. ; Added loop to wait for the shift reg. ; before sending. ; ;Assembly context. ; Files included : COM.EQU.TEXT ; ;Linked to : COM.PKG.P.CODE to obtain : COM.PKG.CODE ; ;Important Additional Info: ; All this code expects to use serial port 1 on the IBM PC or compatibles. ; No allowance is made for machines with no serial port installed. ; ;%} ; .include com.equ.text ; ; int_hndlr - handles interrupts generated by the remote serial port ; .PROC int_hndlr ; *WARNING* - this routine MUST NOT be .REL .def dataseg, ivecofst, int_segment, start_tdata, end_tdata, size_tdata .def tdata, rdata, start_rdata, end_rdata, size_rdata .def handleraddr push bp push ds push es push di push ax push bx push cx push dx ; set up data segment mov ax,cs:dataseg mov ds,ax mov es,ax ; find out where interrupt came from and jump to routine to handle it mov dx,iir in al,dx cmp al,rd jz rcv_chk ; if it's from the receiver cmp al,wr jz tmit_chk ; if it's from the transmitter cmp al,lstat jz lstat_int ; interrupt becuase of line status cmp al,mstat jz mstat_int ; interrupt because of modem status jmp int_end ; interrupt when no interrupt pending, go away lstat_int: mov dx,lsr ; clear interrupt in al,dx jmp repoll ; see if any more interrupts mstat_int: mov dx,msr ; clear interrupt in al,dx jmp repoll ; see if any more interrupts tmit_chk: mov dx,lsr in al,dx and al,tcheck jz repoll ; transmitter not yet ready, ; so see if any more interrupts .public SndSuspended goodtx: test ss:SndSuspended, 1 jnz $1 cmp size_tdata,0 ; see if any more data to send jne have_data ; if not equal then there is data to send ; if no data to send, or host sent XOff, then reset tx interrupt and return $1 call StopWriting jmp repoll have_data: TSRReadyFlag .equ 01000000T ; the LSR bit indicating the Transmitter ; Shift Register is ready. xor cx, cx ; prepare to leave loop eventually no matter what mov dx, lsr $1 in al, dx ; repeatedly obtain the line status test al, TSRReadyFlag jnz $2 ; until the xmit shift register shows ready. loop $1 ; (or 65536 iterations done: more than enough) $2 mov bx,start_tdata ; bx points to next char. to be sent mov dx,datreg ; dx equals port to send data to mov al,tdata(bx) ; get data from buffer out dx,al ; send data inc bx ; increment start_tdata cmp bx,tsize ; see if gone past end jl ntadj ; if not then skip sub bx,tsize ; reset to beginning ntadj: mov start_tdata,bx ; save start_tdata dec size_tdata ; one less character in x-mit buffer jmp repoll rcv_chk: mov dx,lsr ; check and see if read is real in al,dx and al,rcheck ; look at receive data bit jnz good_rx ; real, go get byte jmp repoll ; go look for other interrupts good_rx: mov dx,datreg in al,dx ; get data call CtrlCheck ; check that data is not flow control jz repoll ; if it is, don't add it to the queue cmp size_rdata,rsize ; see if any room jge repoll ; if no room then look for more interrupts mov bx,end_rdata ; bx points to free space mov rdata(bx),al ; send data to buffer inc size_rdata ; got one more character inc bx ; increment end_rdata pointer cmp bx,rsize ; see if gone past end jl nradj ; if not then skip sub bx,rsize ; else adjust to beginning nradj: mov end_rdata,bx ; save value call SizeCheck repoll: mov dx,lsr ; we always expect receive data, so in al,dx ; check status to see if any is ready. and al,rcheck ; get received data bit jnz good_rx ; yes, go accept the byte mov dx,ier ; look at transmit condition in al,dx ; to see if we are enabled to send data and al,txint jz int_end ; not enabled, so go away mov dx,lsr ; we are enabled, so look for tx condition in al,dx and al,tcheck jz int_end jmp goodtx ; transmitter is finished, go get more data int_end: mov dx,ocw2 ; tell the 8259 that I'm done mov al,eoi out dx,al pop dx pop cx pop bx pop ax pop di pop es pop ds pop bp iret ; StopWriting - disables the xmitter-ready interrupt StopWriting: mov dx,ier mov al,rxint out dx,al ret SizeCheck: ; check whether receive buffer is now more than 1/4 full: cmp size_rdata, rsize//4 jle rdfinished ; if it is, and XOn/XOff is being used, and XOff hasn't been sent yet, ; send an XOff to the char-write routine, and set RcvSuspended TRUE .ref WrAppender ; use the char-write routine to send XOff .public ISendXOnXOff, RcvSuspended mov bl, ss:ISendXOnXOff mov dl, ss:RcvSuspended not dl and bl, dl and bl, 1 ; read only bit 0 jz rdfinished ; if XOff has been sent, don't resend mov ax, XOff ; passing conventions use whole word push ax CallRel WrAppender mov ss:RcvSuspended, TRUE rdfinished: ret ; ; CtrlCheck - checks if character now in al is flow control character. ; returns with ZF reset if it is not. CtrlCheck: .public IHnrXOnXOff, SndSuspended test ss:IHnrXOnXOff, 1 ; if honouring incoming Xon/XOff, jnz CharCheck ; check for particular code mov bl, al ; otherwise force reset of zero flag, not bl ; and return cmp bl, al ret CharCheck: cmp al, XOn ; if incoming is XOn, kill any suspension jne XOffCheck mov ss:SndSuspended, FALSE mov dx,ier ; and restore xmit-ready interrupt mov al,rxint .or txint out dx,al ret XOffCheck: cmp al, XOff jne checkdone mov ss:SndSuspended, TRUE CheckDone: ret handleraddr .word int_hndlr dataseg .word 0 ivecofst .word 0 ; the original interrupt offset int_segment .word 0 ; the original interrupt segment start_tdata .word 0 ; index to first character in x-mit buffer end_tdata .word 0 ; index to first free space in x-mit buffer size_tdata .word 0 ; number of characters in x-mit buffer start_rdata .word 0 ; index to first character in rec. buffer end_rdata .word 0 ; index to first free space in rec. buffer size_rdata .word 0 ; number of characters in rec. buffer tdata .block tsize ; dup(?) ; transmit buffer rdata .block rsize ; dup(?) ; receive buffr ; ; init_rem ; initialize the Intel 8250 and set up interrupt vector to int_hndlr ; .relproc InitRem .ref handleraddr, dataseg, intsegment, ivecofst push bp mov bp,sp cli ; make sure no interrupts during int.vec change mov ax,ds mov cs:dataseg,ax mov dx,lsr ; reset line status condition in al,dx mov dx,datreg ; reset receive data condition in al,dx mov dx,msr ; reset modem deltas and conditions in al,dx ; set interrupt vector ;save current DS, and reset it to address from 0:0 push ds xor ax, ax mov ds,ax ;save the pointer at int_off in cx and bx: mov bx,ds:int_off mov cx,ds:int_off+2 mov ax, cs:handleraddr ; prevent any interrupts, and set the routine pointer to cs:<handler> cli movm ds:<int_off+0>, ax movm ds:<int_off+2>,cs pop ds ; save the recovered pointer in the handler's data area: mov ivecofst,bx mov int_segment,cx ; enable interrupts on 8259 and 8250 in al,imr ; set enable bit on 8259 and al,int_mask out imr,al mov dx,ier ; enable interrupts on 8250 mov al,rxint out dx,al mov dx,mcr ; set dtr and enable int driver mov al,dtr out dx,al sti pop bp retl ; ; TurnOffSerial - turns off serial interrupt raising at the serial port ; and the interrupt controller. ; .relproc TurnOffSerial ; turn off 8250 mov dx,ier mov al,0 out dx,al ; turn off 8259 mov dx,imr in al,dx or ax, .not int_mask out dx,al retl ; ; RemoveHandler - unlinks ComPackages interrupt handler from ; the interrupt vector, returning to it ; whatever was there when the package initialised. ; .relproc RemoveHandler .ref int_segment, ivecofst ; reset interrupt vector cli mov bx,ivecofst mov cx,int_segment push ds xor ax, ax mov ds, ax movm ds:<int_off+0>,bx movm ds:<int_off+2>,cx pop ds sti retl .end <<<<<<<<<<<<<<<<<<<<<<<<<<< ;{% 8088/6 routines to set communications parameters for ComPackage. ;File Name : COM.STNG Code Name : COM.STNG (i.e. COM.SeTtiNGs) ; ;History: ; (Adapted from code for MS-Pascal by John Romkey and Jerry Saltzer of MIT ; by Richard Gillmann (GILLMANN@ISIB), 1983. Taken from COM_PKG1.ASM ; from the INFO-IBMPC repository at the University of Southern California.) ;Date Coder Modification ; Jan-April 86 Alastair Milne Adapted to p-System conventions, ; added setting of word length, stop bits, ; and parity; ; added FlushAll to clear I/O queues. ; separated baud rate setting into own routine. ; collapsed DTR_on and DTR_off into SetDTR. ;Assembly context. ; Files included : COM.EQU>TEXT ; ;Linked to : COM.PKG.P.CODE to obtain : COM.PKG.CODE ; ;%} ; .include com.equ.text .RELPROC SetBaudDivisor, 1 ; Place the passed argument in the baud rate divisor latch. mov bp, sp mov dx,lcr in al, dx or al, dla ; set 8th bit of LnCtrlReg on, ; so that 3F8H addresses divisor latch. out dx,al mov dx,dll mov al,(bp+4) ; low byte of passed argument out dx,al mov dx,dlh mov al,(bp+5) ; high byte of passed argument out dx,al mov dx, lcr in al, dx and al, 7FH ; turn off 8th bit again, ; so 3F8H addresses Xmit/Recv buffer. out al, dx retl 2 .RELPROC SetWordLength, 1 ; Sets the Line Control Register to use a word length of the value ; of the passed argument, either 7 or 8. Any other value is ignored. SevenDataBits .equ 10T EightDataBits .equ 11T mov bp, sp cmp (bp+4), 7 jl ResetDone ; don't do anything if new length < 7 mov ah, SevenDataBits ; in case new length = 7 cmp (bp+4), 8 jg ResetDone ; don't do anything if new length > 8 jne SetBits ; given length = 7 bits, use crnt pattern mov ah, EightDataBits ; given length = 8, get 8 bit pattern SetBits: mov dx, lcr ; get crnt line ctrl settings, in al, dx and al, 11111100T ; and clear word length bits for new setting. or al, ah ; put in new word length setting out al, dx ; and send it back out. ResetDone: retl 2 .RELPROC SetStopBits, 1 ; Sets the Line Control Register to use either 1 or 2 stop bits, ; depending on the parameter. Anything but 1 or 2 is ignored. mov bp, sp mov dx, lcr ; get crnt line ctrl settings in al, dx cmp (bp+4), 1 ; if new number of stop bits = 1, jne Try2 and al, 11111011T ; set stop-bit switch 0 jmp Reset Try2: cmp (bp+4), 2 ; else if it's 2, jne NoChange or al, 00000100T ; set stop-bit switch 1 Reset: out al, dx NoChange: retl 2 .RELPROC SetParity, 1 ; Sets the Line Control Register to use the parity indicated ; by the passed argument. Allowed values are the 5 listed below. ; Any other is ignored. NoParity .equ 0 EvenParity .equ 1 OddParity .equ 2 SpaceParity .equ 3 MarkParity .equ 4 mov bp, sp mov cx, (bp+4) mov dx, lcr ; get crnt line ctrl settings in al, dx cmp cl, NoParity jne TryEven and al, 11000111T ; suppress all parity switches. jmp Reset TryEven: or al, 00001000T ; enable parity switch for all other settings. cmp cl, EvenParity ; if new parity is even, jne TryOdd or al, 00010000T ; suppress break, and stick-parity switch. jmp Reset TryOdd: cmp cl, OddParity ; if new parity is odd, jne TrySpace and al, 11001111T ; suppress stick- and even-parity. jmp Reset TrySpace: or al, 00100000T ; turn on the stick-parity switch for the rest. cmp cl, SpaceParity jne TryMark or al, 00111000T ; turn on stick-, even-, and enable switches. jmp Reset TryMark: cmp cl, MarkParity jne NoChange and al, 11101111T ; turn off even-par switch. Reset: out al, dx NoChange: retl 2 ; ; SetDTR - turns off dtr to tell modems that the terminal has gone away ; and to hang up the phone ; .relproc SetDTR, 1 ; bit 0 of parameter is new DTR setting mov dx,mcr mov bp, sp test (bp+4), 1 ; check whether bit 0 is 1 jnz $1 mov al,dtr_of ; if not, set up DTR-off mask jmp $2 $1 mov al, dtr ; if so, set up DTR-on mask $2 out dx, al ; set modem ctrl reg to new mask retl 2 ; ; Break - causes a break to be sent out on the line ; .relproc Break mov dx,lcr ; save the line control register in al,dx mov bl,al or al,brkbit ; set break condition out dx,al mov cx,500 ; delay a while delay: loop delay mov al,bl ; restore the line control register out dx,al retl ; FlushAll - resets all queue pointers to zero, dropping any contents. ; Doesn't affect interrupt servicing. ; .RELPROC FlushAll .ref start_tdata, end_tdata, size_tdata .ref start_rdata, end_rdata, size_rdata xor ax, ax mov start_tdata, ax mov end_tdata, ax mov size_tdata, ax mov start_rdata, ax mov end_rdata, ax mov size_rdata, ax retl .END <<<<<<<<<<<<<<<<<<<<<<<<<<< ;{% remote serial output management routines for ComPackage ;File Name : COM.WRT.TEXT Code Name : COM.WRT.CODE ; ;History: ; (Adapted from code for MS-Pascal by John Romkey and Jerry Saltzer of MIT ; by Richard Gillmann (GILLMANN@ISIB), 1983. Taken from COM_PKG1.ASM ; from the INFO-IBMPC repository at the University of Southern California.) ;Date Coder Modification ; Jan-April 86 Alastair Milne Adapted to p-System conventions. ; Added SendStr for string-oriented output. ; Interrupts cleared for char-add and ; string-add so handler won't try to send ; during routines' execution. ;Assembly context. ; Files included : COM.EQU.TEXT ; ;Linked to : COM.PKG.P.CODE to obtain : COM.PKG.CODE ; ;Important Additional Info: ; Neither write routine (string or character) checks whether there is room ; left in the output queue for what they will add. If there is none, ; they will overwrite the existing contents. The function RemWrtSpace ; is exported to permit the user to make this check if desired. ;%} .include com.equ.text ; ; RemWrtSpace - returns the amount of free space remaining in the transmit buffer ; .relfunc RemWrtSpace .ref size_tdata push bp mov bp, sp mov ax,tsize ; get the size of the x-mit buffer sub ax,size_tdata ; subtract the number of bytes used mov (bp+6), ax pop bp retl ; ; SendCh(ch:byte) - the passed character is put in the transmit buffer ; *WARNING* does not check that there is room to hold the character. .relproc SendCh, 1 .ref end_tdata, tdata, size_tdata .def IntrAddr, WrAppender push bp cli ; keep intrpt handler out while adding the char. mov bp,sp mov bx,end_tdata ; bx points to free space mov al,(bp+6) ; move data from stack to x-mit buffer mov tdata(bx),al inc bx ; increment end_tdata to point to free space cmp bx,tsize ; see if past end jl L4 ; if not then skip sub bx,tsize ; adjust to beginning L4: mov end_tdata,bx ; save new end_tdata inc size_tdata ; one more character in x-mit buffer call IntrOn L44: sti pop bp retl 2 IntrOn: mov dx,ier ; see if tx interrupts are enabled in al,dx and al,txint or al,al jnz $1 mov al,rxint+txint ; if not then set them out dx,al $1 ret IntrAddr .word IntrOn WrAppender .word SendCh, CS ; the intersegment address of this ; relproc. ; second word must be set to current CS ; at runtime, BEFORE any indirect ; calls to this routine. ; ; SendStr(var Out: string); ; *WARNING* does NOT check that the buffer has room for the string. .relproc SendStr, 1 ; parameter points to byte 0 of string in SS. OutStrPtr .equ 4 .ref end_tdata, tdata, size_tdata, IntrAddr, WrAppender mov bp, sp cld ; make sure str instructions move ahead in mem. ;put length byte into cl, move si to string[1], and zero ch: mov si, (bp+OutStrPtr) mov cl, ss:(si) inc si xor ch, ch jcxz finished ; if the string is empty, send is finished push cx ; save the length (loop will zero cx) mov di, end_tdata ; di now indexes (NOT pointing) last buffer pos. cli ; keep intrpt handler out while adding the string. ; append cx characters from the string to the buffer: nextchar: seg ss lodsb ; al <= new char, si <= si + 1 mov es:tdata(di), al ; buffer[di] <= new char inc di cmp di, tsize ; has buffer index reached buffer end? jl moveup ; no: go for next character. xor di, di ; yes: wrap it to start of buffer. moveup: loop nextchar pop cx ; recover the string's length, add cs:size_tdata, cx ; and augment the queue size by it. mov cs:end_tdata, di ; adjust permanent buffer index. sti call cs:(IntrAddr) ; make sure transmitter-ready intrpt is on. finished: retl 2 ; ; wlocal(ch:byte) - writes a character to the input buffer ; .relproc wlocal, 1 .ref size_rdata, end_rdata, rdata push bp mov bp,sp cli cmp size_rdata,rsize ; see if any room jge L14 ; if no room then quit mov bx,end_rdata ; bx points to free space mov al,(bp+6) ; get data mov rdata(bx),al ; send data to buffer inc size_rdata ; got one more character inc bx ; increment end_rdata pointer cmp bx,rsize ; see if gone past end jl L13 ; if not then skip sub bx,rsize ; else adjust to beginning L13: mov end_rdata,bx ; save value L14: sti pop bp retl 2 .end <<<<<<<<<<<<<<<<<<<<<<<<<<< ;{% the remote serial input management routines of ComPackage. ;File Name : COM.READ.TEXT Code Name : COM.READ.CODE ; ;History: ; (Adapted from code for MS-Pascal by John Romkey and Jerry Saltzer of MIT ; by Richard Gillmann (GILLMANN@ISIB), 1983. Taken from COM_PKG1.ASM ; from the INFO-IBMPC repository at the University of Southern California.) ;Date Coder Modification ; Jan-April 86 Alastair Milne Adapted existing char read and char count ; routines to p-System. ; Added routine to return string of chars. ; from input queue. ;Assembly context. ; Files included : COM.EQU.TEXT ; ;Linked to : COM.PKG.P.CODE to obtain : COM.PKG.CODE ; ;%} .include com.equ.text ; ; RemReadCount - returns number of bytes in the receive buffer ; .relfunc RemReadCount .ref size_rdata push bp mov bp, sp mov ax,size_rdata ; get number of bytes used mov (bp+6), ax pop bp retl ; ; RemChRead - returns the next character from the receive buffer and ; removes it from the buffer ; .relfunc RemChRead .ref start_rdata, rdata, size_rdata mov bx,start_rdata ; set bx to index the front of the read queue mov al,rdata(bx) ; put the char to read in low byte and zero high xor ah, ah mov bp, sp ; put ax on the stack as function result mov (bp+4), ax inc bx ; bump start_rdata so it points at next char cmp bx,rsize ; see if past end jl $1 ; if not then skip sub bx,rsize ; adjust to beginning $1: mov start_rdata,bx ; save the new start_rdata value dec size_rdata ; one less character jnz $2 call Restore ; if buffer now empty, make sure further input ; not prevented by XOff $2: retl Restore: ; assumes the read buffer is now empty, or almost. If UsingXOnXOff and ; Suspended are set, sends an XOn, and resets Suspended .public ISendXOnXOff, RcvSuspended .def RestoreAddr .ref WrAppender ; export my own address in WrAppender ; if lowest bit of (ISendXOnXOff AND RcvSuspended) is set ... mov bl, ss:ISendXOnXOff mov dl, ss:RcvSuspended and bl, dl and bl, 1 jz $1 mov ax, XOn ; pass XOn to the public SendCh routine push ax CallRel WrAppender mov ss:RcvSuspended, FALSE ; indicate reception is now suspended. $1 ret RestoreAddr .word Restore ; RemStrRead - moves the characters at the head of the remote input queue ; into a Pascal string, adjusting the queue pointers and size ; indicator accordingly. .relproc RemStrRead, 2 ; first parameter is pointer to string ; length byte ; second is maximum length to be read. OutStr .equ 6 MaxLength .equ 4 .ref start_rdata, rdata, size_rdata mov bp, sp ; set si to index of first char. to read from buffer: mov si, cs:start_rdata ; point es:di to zero'th byte of parameter string: mov di, (bp+OutStr) push ss pop es ; set cx to lesser of: number of chars. in buffer; or max. length mov cx, size_rdata cmp cx, (bp+MaxLength) jle $1 mov cx, (bp+MaxLength) $1: cld ; store the length count into the string's length byte (ie. string[0]) mov al, cl stosb ; if the string is empty, just return jcxz retstr push cx ; save count, for subtraction after loop ; run si along the queue, appending cx characters to the parameter string: nextchar: mov al, rdata(si) ; get each byte from the buffer, inc si stosb ; and append it to the string. cmp si, rsize ; if si now at end of buffer area, jl $2 xor si, si ; wrap it around to the beginning $2: loop nextchar ; if more left to read, do another pass pop cx ; recover original count (loop has 0'd it) sub size_rdata, cx ; and reduce current queue size by it. retstr: mov start_rdata, si ; update reading pointer to new start. or size_rdata, 0 ; if no more left in incoming queue, jnz $1 .ref RestoreAddr call cs:(RestoreAddr) ; make sure XOff isn't suppressing it. $1 retl 4 .end <<<<<<<<<<<<<<<<<<<<<<<<<<< {% UCSD Pascal library UNIT to service remote serial interrupts. File Name : COM.PKG.P.TEXT Code Name: COM.PKG.P.CODE History: Date Coder Modification Jan-Apr 86 Alastair Milne Creation of Pascal interface for assembly routines: - string and character write routines - string and character read routines - report of chars. to read and space for write - routines to change communications params. - routines to set DTR and send break signal - routine to flush I/O queues - flags to set or reset XOn/XOff flow control Automatic initialisation installs handler and enables serial interrupts. Automatic termination restores original interrupt vector entry and disables serial interrupts. Compilation context: Prefix for Compilation: None Units used : None Files included : None Linked to : COM.READ.CODE COM.WRT.CODE COM.STNG.CODE COM.PKG1.CODE To obtain : COM.PKG.CODE Files used at execution: None Important Additional Info: does NOT handle incoming tabs (ASCII 9). %} unit ComPackage; interface type cpWrdLngRange = 7 .. 8; cpStpBtRange = 1 .. 2; StrRange = 0 .. 255; {the range of lengths a UCSD Pascal string can have.} cpBaudRates = (cpBaud110, cpBaud300, cpBaud1200, cpBaud2400, cpBaud4800, cpBaud7200, cpBaud9600); cpParityTypes = (cpNoParity, cpEvenParity, cpOddParity, cpSpaceParity, cpMarkParity); var ISendXOnXOff: boolean; {set this TRUE if ComPackage is to control incoming flow with XOn/XOff protocol. Initially FALSE. } IHnrXOnXOff: boolean; {set this TRUE if ComPackage is to honour XOn/XOff protocol use by other host. Initially FALSE. } function RemReadCount: integer; { Returns number of characters waiting to be read from serial port. } function RemChRead: char; { Returns character now at front of queue from serial port.} procedure RemStrRead(var StrFromRem: string; MaxLength: StrRange); { Returns all the characters now available from the serial port, or the first MaxLength of them, whichever is less. StrFromRem is returned empty if no characters are available. } function RemWrtSpace: integer; { Returns the number of bytes still available to the write buffer.} procedure RemChWrite(ch: char); { Writes Ch into the output serial buffer. } procedure RemStrWrite(str: string); { Moves Str into the output serial buffer, and makes sure the serial interrupts are set to transmit it.} procedure InWrite(ch: char); { Writes the Ch to the serial input buffer (debugging). } procedure SetBaudRate(NewRate: cpBaudRates); procedure SetWordLength(BitsInWord: cpWrdLngRange); procedure SetStopBits(BitsToStop: cpStpBtRange); procedure SetParity(NewParity: cpParityTypes); procedure SetDTR(DTRSetting: BOOLEAN); { Sets the RS-232C DTR (Data Terminal Ready) pin to DTRSetting. } procedure FlushAll; { Empties the input and output remote serial buffers, but leaves interrupt servicing available. } procedure Break; { Sends the break signal. } procedure CloseRemote; { Closes down the remote serial port and suppresses serial interrupts. Doesn't affect input or output buffer.} implementation var (*WARNING: the xxxSuspended flags are global to give them a permanent lifetime, and to permit them to be communicated among the interrupt servicer, reading, and writing routines. They must NOT be modified by any other routine, or errors in flow control (including possible infinite loops) may result. *) RcvSuspended, {TRUE <==> I have sent XOff to suspend host sending} SndSuspended: {TRUE <==> host has sent XOff to suspend my sending} boolean; Divisor: array[cpBaudRates] of integer; procedure IntHndlr; external; {This is the interrupt handler, to which the hardware interrupt vector points. MUST NOT BE CALLED DIRECTLY BY PASCAL. } {Routines to initialise and terminate serial interrupt servicing: } procedure InitRem; external; {Install interrupt handler, and enable serial interrupts} procedure TurnOffSerial; external; {disable serial interrupts} procedure RemoveHandler; external; {restore original interrupt vector entry} procedure FlushAll; external; {Routines to manage incoming characters:} function RemReadCount (*: integer*); external; function RemChRead (*: char*); external; procedure RemStrRead(*var FromRem: string; MaxLength: StrRange*); external; {Routines to manage outgoing characters:} function RemWrtSpace (*: integer*); external; procedure SendCh(ch: char); external; {add ch to output queue} procedure SendStr(var OutStr: string); external; {add outstr to output queue} {Debugging routine to append characters to input queue:} procedure WLocal(ch: char); external; {Routines to control transmission parameters: } procedure SetBaudDivisor(Divisor: integer); external; procedure SetWordLength(*BitsInWord: cpWrdLngRange*); external; procedure SetStopBits(*BitsToStop: cpStpBtRange*); external; procedure SetParity(*NewParity: cpParityTypes*); external; procedure SetDTR(*DTRSetting: BOOLEAN*); external; procedure Break; external; procedure SetBaudRate(*NewRate: cpBaudRates*); begin SetBaudDivisor(Divisor[NewRate]); end; procedure CloseRemote; begin TurnOffSerial; RemoveHandler; end; procedure RemChWrite(*ch: char*); begin while RemWrtSpace < 5 do; {make sure serial output queue has enough space: wait until some is dumped. } SendCh(ch); end; procedure RemStrWrite(*Str: string*); begin while RemWrtSpace < length(Str) do; {wait until the hardware has dumped enough of the buffer to admit the new string.} SendStr(Str); end; procedure InWrite(*ch: char*); begin WLocal(ch); end; begin {automatic initialisation: set baud rate divisors (taken from table); NOTE: these values should work for most IBM PC compatibles, but they WON'T work for the PC jr, which uses different divisors. set flags for no flow control; install handler and enable serial interrupts.} Divisor[cpBaud110] := 1047; Divisor[cpBaud300] := 384; Divisor[cpBaud1200] := 96; Divisor[cpBaud2400] := 48; Divisor[cpBaud4800] := 24; Divisor[cpBaud7200] := 16; Divisor[cpBaud9600] := 12; ISendXOnXOff := false; RcvSuspended := false; IHnrXOnXOff := false; SndSuspended := false; InitRem; {automatic termination: turn off serial interrupts and restore the original interrupt vector entry: } ***; TurnOffSerial; RemoveHandler; end.