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Text File | 1986-12-29 | 18.5 KB | 533 lines

page ;*********************************************************** ;** ** ;** Device Driver for RS232 communications ** ;** Copyright (C) Texas Instruments 1986 ** ;** Author: Greg Haley ** ;** ** ;** THIS SOURCE CODE MAY BE DISTRIBUTED AND MODIFIED ** ;** ONLY IF THE ORIGINAL COPYRIGHT AND AUTHOR CREDITS ** ;** REMAIN INTACT. ** ;** ** ;** Project Start Date: 09/09/86 ** ;** ** ;** Re: 10/14/86 by Greg Haley ** ;** Added more delays (jmp $+2) for more tolerant ** ;** timing. Also increased stacks to 80 words for ** ;** Business Pro compatibility. ** ;** ** ;** Re: 10/15/86 by Greg Haley ** ;** The COMM chip is no longer initialized on every ** ;** write request. ** ;** ** ;** Re: 10/23/86 by Greg Haley ** ;** Added code to block interrupts while setting up ** ;** and restoring the stack. ** ;** ** ;** Re: 11/07/86 by Greg Haley ** ;** Added option to echo RS232 I/O to the CRT. ** ;** ** ;** Re: 11/13/86 by Greg Haley ** ;** Save SI and AX when calling DOS fast write. ** ;** Changed SAR's and SAL's to SHR's and SHL's. ** ;** Added keyboard input in parallel with RS232 input. ** ;** ** ;** Re: 11/20/86 by Greg Haley ** ;** Modified I/O channel commands so that a more ** ;** standard structure could be used, and to make it ** ;** easier to add new commands in the future. Also, ** ;** all machine dependent code was moved to a seperate ** ;** file to allow new machines to be added much more ** ;** easily. ** ;** ** ;** Re: 12/29/86 by Greg Haley ** ;** Fixed bug in XON-XOFF busy handling where XON ** ;** was not sent to reset the busy condition. ** ;** ** ;*********************************************************** cr equ 13 lf equ 10 fast_write equ 29h ; DOS INT for fast CRT write com1_tbl: ;header for device dw -1 dw -1 dw 1100000000000000B ; CHAR device with I/O control dw strategy dw entry db 'AUX ' ; Device name to use ; command jump table cmdtbl: dw init dw exit dw exit dw ioctl_in dw read dw nd_read dw input_status dw input_flush dw write dw write dw output_status dw exit dw ioctl_out dw exit dw exit dw exit dw exit oldss dw 0 ; Old SS reg oldsp dw 0 ; Old SP reg dw 80 dup (?) ; New stack e_stack label word ptrsav dd 0 ; DOS cmd block pointer init_once db 0 ; flag for init echo_in db 0 ; Echo input to console flag echo_out db 0 ; Echo output to console flag key_in db 0 ; Parallel keyboard input flag dcw_len db 0 ; DCW (0) or Length (not 0) mode page ;*********************************************************** ;** Device Driver Entry ** ;*********************************************************** cmdlen = 0 ;length of this command unit = 1 ;sub unit specifier cmd = 2 ;command code status = 3 ;status media = 13 ;media descriptor trans = 14 ;transfer address count = 18 ;count of blocks or characters start = 20 ;first block to transfer ;*********************************************************** ;** Strategy Routine ** ;*********************************************************** stratp proc far strategy: mov word ptr cs:[ptrsav],bx mov word ptr cs:[ptrsav+2],es ret stratp endp ;*********************************************************** ;** Entry Routine ** ;*********************************************************** entry: cli ; disable ints mov cs:word ptr oldss,ss mov cs:word ptr oldsp,sp mov sp,cs mov ss,sp mov sp,offset e_stack sti ; enable ints push si push ax push cx push dx push di push bp push ds push es push bx lds bx,cs:[ptrsav] ;get pointer to i/o packet mov cx,word ptr ds:[bx].count ;cx = count mov al,byte ptr ds:[bx].cmd ; al = command cbw mov si,offset cmdtbl add si,ax add si,ax cmp al,16 ja cmderr les di,dword ptr ds:[bx].trans push cs pop ds cld assume ds:code jmp word ptr [si] ;go do command page ;*********************************************************** ;** Device Driver Exit ** ;*********************************************************** bus$exit: ;device busy exit mov ah,00000011b jmp short done cmderr: mov al,3 ;unknown command error err$exit: mov ah,10000001b ;mark error return jmp short done exitp proc far exit: mov ax,0000000100000000b done: lds bx,cs:[ptrsav] mov word ptr [bx].status,ax ;mark operation complete pop bx pop es pop ds pop bp pop di pop dx pop cx pop ax pop si ; restore stack cli ; disable ints mov ss,cs:word ptr oldss mov sp,cs:word ptr oldsp sti ; enable ints ret ;restore regs and return exitp endp page ;*********************************************************** ;** Write Routine ** ;** ** ;** ES:DI contain xfer adrs on entry ** ;** CX contains num chars to write ** ;** ** ;** ** ;*********************************************************** write proc near push es ; Move pointer to DS:SI pop ds mov si,di mov dx,cs:word ptr send_buffer ; xmit port send_chars: lodsb ; al now has char cmp cs:byte ptr echo_out,0 ; Echo output on? jz no_echo_out ; No, skip push si push ax int fast_write ; Yes, echo to console pop ax pop si no_echo_out: write_1: cmp cs:byte ptr t_busy,0 ; Is device busy? jne write_1 ; Yes, loop again x_busy: cmp cs:byte ptr xmit_busy,0 ; Is transmitter busy? jne x_busy ; Yes, wait for it out dx,al mov cs:byte ptr xmit_busy,1 ; We're busy now loop send_chars ; look for more chars jmp exit write endp page ;*********************************************************** ;** Non Destructive Read Routine ** ;** ** ;** On entry, ES points to buffer segment ** ;*********************************************************** nd_read proc near mov di,13 ; point to byte buffer cmp cs:byte ptr key_in,0 ; Look for keyboard input? jz nd_read_0 ; No, skip push cx push di call k_ready ; Is a char waiting? pop di pop cx jz nd_read_0 ; No, skip stosb ; Yes, store it jmp exit ; We're done nd_read_0: cmp cs:word ptr rq_len,0 ; Any chars in receive buffer? jnz nd_read_1 ; Yes, continue mov ah,00000011b ; Set busy & done jmp done ; We're done nd_read_1: mov bx,offset rqueue ; Get queue ptr mov dx,cs:word ptr rq_tail add bx,dx ; point at char mov al,byte ptr[bx] ; al now has char cmp cs:byte ptr echo_in,0 ; Echo input on? jz no_echo_in ; No, skip push si push ax int fast_write ; Yes, echo to console pop ax pop si no_echo_in: stosb ; store char in buffer jmp exit nd_read endp page ;*********************************************************** ;** Get Input Status ** ;*********************************************************** input_status proc near cmp cs:byte ptr key_in,0 ; Look for keyboard input? jz in_stat_0 ; No, skip call k_ready ; Is a char waiting? jnz xit_in_stat ; Yes, exit in_stat_0: cmp cs:word ptr rq_len,0 ; Any chars in receive buffer? jnz xit_in_stat ; Yes, continue mov ah,00000011b ; No, set busy & done jmp done ; We're done xit_in_stat: jmp exit ; Normal exit code input_status endp page ;*********************************************************** ;** Flush Input Buffer ** ;*********************************************************** input_flush proc near mov cs:word ptr rq_head,0 ; Head = 0 mov cs:word ptr rq_tail,0 ; Tail = 0 mov cs:word ptr rq_len,0 ; make queue length 0 jmp exit ; Normal exit code input_flush endp page ;*********************************************************** ;** Get Output Status ** ;*********************************************************** output_status proc near cmp cs:byte ptr t_busy,0 ; Are we busy? je xit_out_stat ; No, continue mov ah,00000011b ; Set busy & done jmp done ; We're done xit_out_stat: jmp exit ; Normal exit code output_status endp page ;*********************************************************** ;** Read Routine ** ;** ** ;** ES:DI contain xfer adrs on entry ** ;** CX contains num chars requested ** ;*********************************************************** read proc near cmp cs:byte ptr key_in,0 ; Look for keyboard input? jz read_0 ; No, skip push cx push di call k_ready ; Is a char waiting? pop di pop cx jz read_0 ; No, skip mov cx,1 call update_count push di call k_read ; Get char from keyboard pop di stosb jmp exit ; We're done read_0: mov ax,cs:word ptr rq_len ; Any chars in recv buffer? or ax,ax jnz read_1 ; Yes, continue xor cx,cx ; No, return 0 chars received call update_count jmp exit ; We're done read_1: ; figure out how many chars to get cmp ax,cx ; More than DOS buffer? jg read_2 ; Yes, CX already has count mov cx,ax ; No, only send what we have read_2: call update_count ; update chars received mov bx,offset rqueue ; Get queue ptr mov dx,cs:word ptr rq_tail read_3: add bx,dx ; point at char mov al,byte ptr[bx] ; al now has char cmp cs:byte ptr echo_in,0 ; Echo input on? jz not_echo_in ; No, skip int fast_write ; Yes, echo to console not_echo_in: stosb ; store char in buffer inc dx and dx,recv_limit ; wrap if >= limit mov cs:word ptr rq_tail,dx ; update tail dec cs:word ptr rq_len ; Adjust queue length loop read_3 ; Loop again ; reset busy if we can cmp cs:word ptr rq_len,not_busy_len ; Room for more chars? jg read_4 ; No, skip mov cs:byte ptr r_busy,0 ; Yes, reset busy call send_xon ; Send XON char if needed read_4: jmp exit read endp page ;*********************************************************** ;** Write I/O Control Channel ** ;** ** ;** ES:DI contain xfer adrs on entry ** ;** CX contains count ** ;*********************************************************** ioctl_out proc near push es ; Move pointer to DS:SI pop ds mov si,di cmp cx,2 ; Is it a DCW? je ioo_1 ; Yes, continue cmp cx,1 ; Is it a CSB? jz ioo_nc0 ; Yes, continue jmp exit ; No, exit ioo_nc0: lodsb ; Yes, get the byte push cs ; DS = CS pop ds mov ah,al ; Update echo output and ah,00100000b mov echo_out,ah mov ah,al ; Update echo input and ah,01000000b mov echo_in,ah mov ah,al ; Update keyboard input and ah,10000000b mov key_in,ah mov ah,al ; Update DCW/LEN mode and ah,00000100b mov dcw_len,ah test al,00000001b ; Drop RS232 signals? jnz ioo_nc1 ; No, skip call de_init ; Yes, disconnect mov byte ptr dcw_len,0 ; Reset to DCW mode ioo_nc1: test al,00000010b ; Flush input buffer? jz ioo_nc2 ; No, skip jmp input_flush ; Yes, go flush it ioo_nc2: jmp exit ; exit ioo_1: lodsw ; get DCW in AX ; make ds = cs push cs pop ds ; check for serial device test ah,80h ; Serial device? jnz ioo_2 ; Yes, continue jmp exit ; No, exit ioo_2: call set_dcw ; Go set DCW mov word ptr dcw,ax ; Save new DCW call init_comm ; init comm chip jmp exit ioctl_out endp page ;*********************************************************** ;** Read I/O Control Channel ** ;** ** ;** ES:DI contain xfer adrs on entry ** ;*********************************************************** ioctl_in proc near cmp cx,2 ; Is it a word? je is_2byte ; Yes, go get it cmp cx,1 ; Is it a byte? jne ioi_xit ; No, exit xor al,al ; Clear status byte or al,cs:byte ptr m_stat ; Update current modem status or al,cs:echo_out ; Update echo output or al,cs:echo_in ; Update echo input or al,cs:key_in ; Update keyboard input stosb ; and pass it to DOS jmp exit is_2byte: cmp cs:byte ptr dcw_len,0 ; DCW mode? jz ioi_1 ; Yes, get DCW mov ax,cs:rq_len ; No, get receive queue length jmp short ioi_2 ioi_1: mov ax,cs:dcw ; Get DCW ioi_2: stosw ; and pass it to DOS ioi_xit: jmp exit ioctl_in endp page ;*********************************************************** ;** Return Number of Chars Processed ** ;** ** ;** CX contains number of characters processed ** ;*********************************************************** update_count proc near push ds push bx lds bx,cs:[ptrsav] ;get pointer to i/o packet mov word ptr ds:[bx].count,cx ;cx = count pop bx pop ds ret update_count endp