Power-Programmierung

home *** CD-ROM | disk | FTP | other *** search

/ Power-Programmierung / CD1.mdf / assemblr / library / async / comasm.asm < prev

Wrap

Assembly Source File | 1992-01-12 | 46.2 KB | 1,604 lines

PAGE 63,132 ;(63 lines long, 132 columns wide) TITLE Mark Stout COMASM 5/10/89 .SALL ;============================================================================== ; ; Mark Stout COMASM.EXE 5/10/89 ; ; COMASM is an integrated terminal emulation package combining two modes, ; VT52 and CHAT. While in the VT52 emulation mode, COMASM will impersonate ; a DEC VT52, transmitting, receiving and interpreting all escape ; sequences in this terminal's command set. While in the CHAT mode, COMASM ; allows messages to be sent between two PCs. Any characters ; may be sent, in messages up to 256 characters long. ; ; Data is transmitted and received through the PC's primary serial port, ; COM1. COMASM relies on interupts from the UART as opposed to polling ; its registers. ; ;============================================================================== ;^^^^^^^^^^^^^^^^^^^^^^^^^^^^MACROS^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ;============================================================================== ; ; DISPLAY Macro: ; ; Displays string of characters on standard output. String must be ; terminated by '$'. ; ; Format: ; ; DISPLAY message ; ; where message is the offset of the string. ; ;============================================================================== DISPLAY MACRO MESSAGE PUSH DX PUSH AX LEA DX, MESSAGE ;Point to offset of string MOV AH, 9H ;Use DOS function 9H INT 21H POP AX POP DX ENDM ;============================================================================== ; ; BIN2ASCII Macro: ; ; Converts binary value in DX to ASCII string. ; ; Format: ; ; BIN2ASCII length, out_buffer ; ; where length is the # of characters for the output string, including ; leading spaces, and out_buffer is location of output buffer. ; ;============================================================================== BIN2ASCII MACRO LENGTH, OUT_BUFFER LOCAL ASCIILOOP, BLANK, NEXT, PAD ;Define local labels for multiple invocations PUSH AX PUSH BX PUSH CX PUSH DX PUSH DI MOV CX, LENGTH ;Set up CX as counter of ASCII digits MOV AX, DX ;Move binary value to accumulator MOV BX, 10 ;Set up BX as decimal base ASCIILOOP: MOV DI, CX ;Use DI for index relative addressing of ASCII string CMP AX, 0 ;If accumulator = 0, pad left of string with blanks JE BLANK MOV DX, 0 ;Prepare DX as high word of dividend DIV BX ;Divide remaining value by decimal base ADD DX, 30H ;Convert remainder to ASCII for use in string MOV [OUT_BUFFER+DI-1], DL ;Converted remainder is next least significant digit in string JMP NEXT BLANK: CMP CX, LENGTH ;Checks for binary value = 0 JNE PAD MOV [OUT_BUFFER+DI-1], '0' JMP NEXT PAD: MOV [OUT_BUFFER+DI-1], ' ' ;Pads left of string with blanks when necessary NEXT: LOOP ASCIILOOP ;Calculate next digit of string POP DI POP DX POP CX POP BX POP AX ENDM ;=============================================================================== ; ; SCROLL_UP Macro: ; ; Uses BIOS function INT 10h, Subfunction 6, to scroll a pre-defined ; window a given number of lines. New lines are white foreground on ; black background. ; ; Format: ; ; SCROLL_UP lines, TL_row, TL_col, BR_row, BR_col ; ; where: lines = # of lines to scroll (0 for entire window) ; TL_row = row of top, left corner ; TL_col = column of top, left corner ; BR_row = row of bottom, right corner ; BR_col = column of bottom, right corner ; ;=============================================================================== SCROLL_UP MACRO LINES, TL_ROW, TL_COL, BR_ROW, BR_COL PUSH AX PUSH BX PUSH CX PUSH DX MOV AH, 6 ;Choose subfunction 6 MOV AL, LINES ;Initialize registers MOV CH, TL_ROW MOV CL, TL_COL MOV DH, BR_ROW MOV DL, BR_COL MOV BH, 7 INT 10H POP DX POP CX POP BX POP AX ENDM ;=============================================================================== ; ; SCROLL_DOWN Macro: ; ; Uses BIOS function INT 10h, Subfunction 6, to scroll a pre-defined ; window down a given number of lines. New lines are white foreground on ; black background. ; ; Format: ; ; SCROLL_DOWN lines, TL_row, TL_col, BR_row, BR_col ; ; where: lines = # of lines to scroll (0 for entire window) ; TL_row = row of top, left corner ; TL_col = column of top, left corner ; BR_row = row of bottom, right corner ; BR_col = column of bottom, right corner ; ;=============================================================================== SCROLL_DOWN MACRO LINES, TL_ROW, TL_COL, BR_ROW, BR_COL PUSH AX PUSH BX PUSH CX PUSH DX MOV AH, 7 ;Choose subfunction 7 MOV AL, LINES ;Initialize registers MOV CH, TL_ROW MOV CL, TL_COL MOV DH, BR_ROW MOV DL, BR_COL MOV BH, 7 INT 10H POP DX POP CX POP BX POP AX ENDM ;=============================================================================== ; ; LOCATE Macro: ; ; Uses BIOS function INT 10h, Subfunction 2, to position cursor. ; ; Input: DH = Row coordinate (0-24) ; DL = Column coordinate (0-79) ; ;=============================================================================== LOCATE MACRO PUSH AX PUSH BX MOV AH, 2 ;Choose subfunction 2 MOV BH, 0 ;Choose video page INT 10H POP BX POP AX ENDM ;^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ STKSEG SEGMENT STACK ;Stack segment DB 512 DUP(?) ;(512 bytes ought to do) STKSEG ENDS CSEG SEGMENT ;Code segment ASSUME CS:CSEG, DS:CSEG, SS:STKSEG, ES:NOTHING ;============================================================================== ; ; MP3 Main Procedure: ; ; Sets up data, and calls subroutines. Also performs requested ; mode switching and exits. ; ;============================================================================== MAIN PROC FAR MOV AX, CSEG ;Initialize DS register MOV DS, AX JMP OLA ;Jump around data ; Define equates, messages and buffers MSGCAP EQU 256 CR EQU 0DH LF EQU 0AH EOM EQU 0DH ESCAPE EQU 27 XON EQU 17 XOFF EQU 19 TOP_BORDER DB "╔═════════════════ OUT ════════════════╗╔═════════════════ IN ═════════════════╗$" BOT_BORDER DB "╚══════════════════════════════════════╝╚══════════════════════════════════════╝$" VERT_BORDER DB "║$" INTRO DB "CHAT MODE: Type anything. ENTER sends each message. Hit ESC to exit.$" FULL_QUEUE DB "Warning: The transmission queue is full. Please hit ENTER to end the message.$" INVALID_MSG DB "Warning: Invalid key was depressed.$" TX_POSITION DW ? RX_POSITION DW ? VT_POSITION DW 0 LMSG DW 0 VECTOR_SEG DW ? VECTOR_OFF DW ? MODE DB ? ;Mode = 3 for VT52 emulation, 1 for CHAT STATUS DB "STATUS: Baud: 1200 Parity: N Data Bits: 8 Stop Bit(s): 1$" APPLICATION DB 0 ;Indicates numeric keypad application mode. ESC_SEQ DB 0 DCADDRESS_LINE DB ? COMM_PAR DB 10000011B ;Communications parameters BAUD_PROMPT DB "Select Baud: A)110 B)150 C)300 D)600 E)1200 F)2400 G)4800 H)9600 $" PARITY_PROMPT DB "Select Parity: N)one E)ven O)dd $" DATA_PROMPT DB "Select Data Bits: 7)Seven 8)Eight $" STOP_PROMPT DB "Select Stop Bits: 1)One 2)Two $" XOFF_MSG DB "Receiced XOFF. Please stop typing.$" FLOW DB 0 ; Call subroutines. OLA: CALL ISR_INIT ;Install new interupt service routine 0Ch VT52: MOV MODE, 3 ;Update mode indicator CALL PORT_INIT CALL VT52_SCREEN CALL CLEAR_QUEUES EMU: CALL VT52_INPUT CMP AL, 0 ;Could character be for program control? JNE NO_ALT CMP AH, 24 ;CHAT for Alt-O JE CHAT CMP AH, 45 ;Exit to DOS for Alt-X JE CIAO NO_ALT: CALL VT52_DISPLAY CALL FLOW_CONTROL ;Handle receipt of XOFF. JMP EMU CHAT: MOV MODE, 1 ;Update mode indicator CALL PORT_INIT CALL CHAT_SCREEN CALL CLEAR_QUEUES GAB: CALL CHAT_INPUT ;Process characters in keyboard buffer CMP AL, ESCAPE ;If escape entered, exit JE VT52 CALL RX_DISPLAY ;Display any received character JMP GAB ;Repeat for next character CIAO: SCROLL_UP 0, 0, 0, 24, 79 ;Blank screen upon exit MOV DX, VECTOR_OFF MOV DS, VECTOR_SEG MOV AX, 250CH ;Install original interrupt vector INT 21H MOV AH,4Ch ;DOS code to exit INT 21h ;(exit) MAIN ENDP ;=============================================================================== ; ; ISR_INIT Subroutine: ; ; Installs new INT 0Ch vector. Saves original vector for restoration. ; ;=============================================================================== ISR_INIT PROC NEAR PUSH AX PUSH BX PUSH DX PUSH ES MOV AX, 350CH ;Get original INT 0Ch vector INT 21H MOV VECTOR_SEG, ES MOV VECTOR_OFF, BX LEA DX, ISR0C ;Find address of new interupt service routine MOV AX, 250CH ;Install vector for new ISR INT 21H POP ES POP DX POP BX POP AX RET ISR_INIT ENDP ;=============================================================================== ; ; ISR0C Interupt Handler: ; ; Alerted by interupt type 0Ch. Checks for type of UART interupt, and ; acts accordingly. If RDA is true, reads character from UART. If THRE ; is true, transmits character from TX queue. ; ;=============================================================================== ISR0C PROC PUSH AX PUSH DX PUSH DI PUSH DS MOV AX, CSEG ;Restore data segment register MOV DS, AX MOV DX, 03FAH ;Check Interupt IN AL, DX ;Identification Register TEST AL, 10B ;Was it a THRE irpt? JNZ THRE MOV DX, 3F8H ;Receive character IN AL, DX CMP AL, XOFF ;Check for XOFF JNE ISR1 MOV FLOW, 0FFH ;Set data flow indicator JMP ISR_DONE ISR1: CMP AL, XON ;Check for XON JNE ISR2 MOV FLOW, 0 ;Reset data flow indicator JMP ISR_DONE ISR2: LEA DI, RQ CALL ENQUEUE ;Enqueue received character JMP ISR_DONE THRE: LEA DI, TQ ;Dequeue character for transmission CALL DEQUEUE MOV DX, 03F8H ;Transmit character OUT DX, AL CMP MODE, 1 ;Disable THRE according to mode JE CHATTER CMP TQ.COUNT, 0 ;Any characters to be sent? JNE ISR_DONE MOV AL, 01B ;If not, disable THRE irpts MOV DX, 03F9H OUT DX, AL JMP ISR_DONE CHATTER: CMP TQ.NMSGS, 0 ;Any more pending messages to be sent? JNE ISR_DONE MOV AL, 01B ;If no more messages pending, MOV DX, 03F9H ;disable THRE irpts OUT DX, AL ISR_DONE: MOV AL, 20H ;Inform UART that ISR is finished OUT 20H, AL POP DS POP DI POP DX POP AX IRET ISR0C ENDP ;=============================================================================== ; ; PORT_INIT Subroutine: ; ; Initializes primary serial port for the parameters determined by AL. ; ; Uses BIOS function INT 14h, Subfunction 0. ; ; Input: COMM_PAR has initialization bit pattern: BBBPPSLL ; ; Output: COM1 is initialized ; ALL REGISTERS PRESERVED ; ;=============================================================================== PORT_INIT PROC NEAR PUSH AX PUSH DX MOV DX, 0 ;Choose primary port MOV AH, 0 ;Indicate subfunction MOV AL, COMM_PAR ;Get communication parameters INT 14H ;Initialize port MOV DX, 3FDH ;Clear out any initial garbage IN AL, DX ;in UART register TEST AL, 1B JE PORT_CLEAR MOV DX, 3F8H ;Receive garbage character IN AL, DX PORT_CLEAR: MOV AL, 01B MOV DX, 03F9H OUT DX, AL ;Enable RDA irpts MOV AL, 1011B ;Set OUT2 of the Modem Control Register MOV DX, 03FCH ;so UART passes Irpts to the 8259 OUT DX, AL ;Also, initiate handshaking through DTR and RTS SHAKE: MOV DX, 03FEH ;Check that modem has completed handshake IN AL, DX AND AL, 00110000B ;Is modem ready to communicate? JZ SHAKE ;If not, wait IN AL, 21H ;Enable IRQ4 interrupts at AND AL, 11101111B ;the 8259 PIC OUT 21H, AL POP DX POP AX RET PORT_INIT ENDP ;=============================================================================== ; ; VT52_SCREEN Subroutine: ; ; Displays status line and positions cursor for VT52 emulation. ; ;=============================================================================== VT52_SCREEN PROC NEAR PUSH DX SCROLL_UP 0, 0, 0, 24, 79 MOV DX, 1800H LOCATE DISPLAY STATUS MOV DX, VT_POSITION LOCATE POP DX RET VT52_SCREEN ENDP ;=============================================================================== ; ; VT52_INPUT Subroutine: ; ; Uses BIOS function INT 16h to check for and retrieve characters typed ; on transmitting keyboard. Queues them into TQ. ; ;=============================================================================== VT52_INPUT PROC NEAR PUSH BX PUSH DI MOV AH, 1 INT 16H JZ VTI_RESET MOV AH, 0 ;Accept character from keyboard INT 16H CMP AL, 0 ;Convert special keys, and flag invalid keys JNE VT_IN1 CALL VT52_SPECIAL CMP AL, 0 ;Don't enqueue invalid characters JE DONE_IN2 VT_IN1: CMP APPLICATION, 0 ;Is keypad in application mode? JE VT_IN2 MOV BL, AL ;If so, add 40 to ASCII value of MOV BH, 0 ;keypad characters as part of ADD AL, APP_CODES[BX] ;VT52 specs PUSH AX MOV AL, ESCAPE ;Send ESC ? before application LEA DI, TQ ;keypad value CALL ENQUEUE MOV AL, "?" CALL ENQUEUE POP AX VT_IN2: LEA DI, TQ ;Enqueue character for transmission CALL ENQUEUE PUSH AX MOV AL, 11B ;Enable THRE irpts, as character(s) MOV DX, 03F9H ;wait for transmission OUT DX, AL POP AX JMP DONE_IN2 VTI_RESET: MOV AX, 0 ;If no key entered reset "new key value" DONE_IN2: POP DI POP BX RET VT52_INPUT ENDP APP_CODES DB 12 DUP(0), 40H, 30 DUP(0), 3 DUP(40H), 0, 10 DUP(40H), 200 DUP(0) ;=============================================================================== ; ; VT52_SPECIAL Subroutine: ; ; Interprets cursor movement and screen control keys. ; Transmits appropriate escape sequence. ; ;=============================================================================== VT52_SPECIAL PROC NEAR PUSH BX PUSH DX PUSH DI CMP AH, 25 ;Change comm. parameters? JNE SPEC1 CALL LINE_SETTINGS JMP FINI SPEC1: CMP AH, 59 ;Don't interpret invalid key press JB FINI CMP AH, 118 JA FINI MOV BL, AH ;Use look-up table of appropriate sequences MOV BH, 0 SUB BX, 50 MOV DL, SPECIAL_CODES[BX] CMP DL, " " ;Don't interpret invalid keys JE FINI MOV AL, DL ;Get ready for enqueuing sequences PUSH AX LEA DI, TQ CMP AL, "J" ;Was it CLEAR SCREEN? JNE SPEC2 MOV AL, ESCAPE ;CLEAR SCREEN is a dual escape sequence CALL ENQUEUE MOV AL, "H" CALL ENQUEUE SPEC2: MOV AL, ESCAPE ;Enqueue esc of sequence CALL ENQUEUE POP AX FINI: POP DI POP DX POP BX RET VT52_SPECIAL ENDP SPECIAL_CODES DB " PQRS HA D C KB J" ;=============================================================================== ; ; VT52_DISPLAY Subroutine: ; ; Interprets and displays received characters. ; ;=============================================================================== VT52_DISPLAY PROC NEAR PUSH AX PUSH BX PUSH DX PUSH DI CMP RQ.COUNT, 0 ;Received characters for display? JE VTD_DONE LEA DI, RQ ;Dequeue next available character CALL DEQUEUE CMP ESC_SEQ, 0 ;Part of esc sequence? JE VTD1 CALL VTD_ESCAPE JMP VTD_DONE VTD1: CMP AL, ESCAPE ;Is character start of escape sequence? JNE VTD2 MOV ESC_SEQ, 0FFH ;Store escape sequence status JMP VTD_DONE VTD2: MOV DX, VT_POSITION ;Position cursor LOCATE MOV AH, 2 ;Display new character MOV DL, AL INT 21H MOV AH, 3 ;Determine new cursor location MOV BH, 0 INT 10H CMP DH, 24 ;Is cursor on status line? JNE VTD3 SCROLL_UP 1, 0, 0, 23, 79 ;Scroll if necessary MOV DH, 23 LOCATE VTD3: MOV VT_POSITION, DX ;Store new cursor location VTD_DONE: POP DI POP DX POP BX POP AX RET VT52_DISPLAY ENDP ;=============================================================================== ; ; VTD_ESCAPE Subroutine: ; ; Moves cursor and/or manipulate screen according to escape sequence. ; ;=============================================================================== VTD_ESCAPE PROC NEAR PUSH AX PUSH DX CMP ESC_SEQ, 0FFH ;Initial character after escape received? JE VE1 ;Yes, jump to code for simple sequences CMP ESC_SEQ, 0FH ;Final character of Direct Cursor Address? JE VE2 ;Yes SUB AL, 20H ;No, calculate specified line for LOCATE macro CMP AL, 23 ;Check to see line is on screen JBE VE3 MOV AL, 23 VE3: MOV DCADDRESS_LINE, AL ;Store lin specified by DCA MOV ESC_SEQ, 0FH JMP VE_DONE VE2: SUB AL, 20H ;Interpret column of DCA CMP AL, 79 JBE VE4 MOV AL, 79 VE4: MOV DL, AL MOV DH, DCADDRESS_LINE JMP VE_LOC ;Locate cursor VE1: MOV DX, VT_POSITION ;Interpret simple escape sequences CMP AL, "A" ;Up arrow? JNE VE5 CMP DH, 0 JE VE_RESET DEC DH JMP VE_LOC VE5: CMP AL, "B" ;Down arrow? JNE VE6 CMP DH, 23 JE VE_RESET INC DH JMP VE_LOC VE6: CMP AL, "C" ;Right arrow? JNE VE7 CMP DL, 79 JE VE_RESET INC DL JMP VE_LOC VE7: CMP AL, "D" ;Left arrow? JNE VE8 CMP DL, 0 JE VE_RESET DEC DL JMP VE_LOC VE8: CMP AL, "H" ;Home cursor? JNE VE9 MOV DX, 0 JMP VE_LOC VE9: CMP AL, "I" ;Reverse Line feed? JNE VE10 CMP DH, 0 JE ROOM DEC DH JMP VE_LOC ROOM: SCROLL_DOWN 1, 0, 0, 23, 79 JMP VE_LOC VE_RESET: ;Reset escape sequence indicator MOV ESC_SEQ, 0 JMP VE_DONE VE10: CMP AL, "J" ;Erase EOS? JNE VE11 CMP DH, 23 JE VE12 CALL CLEAR_BLOCK VE12: CALL ERASE_EOL JMP VE_LOC VE11: CMP AL, "K" ;Erase EOL? JNE VE13 CALL ERASE_EOL JMP VE_LOC VE13: CMP AL, "Y" ;Direct Cursor Address? JNE VE14 MOV ESC_SEQ, 0F0H JMP VE_DONE VE14: CMP AL, "Z" ;Identify Terminal? JNE VE15 CALL IDENTIFY JMP VE_RESET VE15: CMP AL, "=" ;Enter Application Keypad Mode? JNE VE16 MOV APPLICATION, 0FFH JMP VE_RESET VE16: CMP AL, ">" ;Exit App Keypad Mode? JNE VE_RESET MOV APPLICATION, 0 JMP VE_RESET VE_LOC: LOCATE ;Reposition cursor MOV VT_POSITION, DX JMP VE_RESET VE_DONE: POP DX POP AX RET VTD_ESCAPE ENDP ;=============================================================================== ; ; CLEAR_BLOCK Subroutine: ; ; Erases screen below cursor as part of ERASE EOS. ; Uses INT 10, Sub 6 to scroll block. ; ;=============================================================================== CLEAR_BLOCK PROC NEAR PUSH AX PUSH BX PUSH CX PUSH DX MOV AH, 6 ;Choose subfunction MOV AL, 0 ;Load parameters MOV BH, 7 MOV CH, DH INC CH MOV CL, 0 MOV DX, 174FH INT 10H ;Erase block POP DX POP CX POP BX POP AX RET CLEAR_BLOCK ENDP ;=============================================================================== ; ; ERASE_EOL Subroutine: ; ; Erases screen to end of current line. ; Uses INT 10, Sub 6 to scroll line. ; ;================================================================================ ERASE_EOL PROC NEAR PUSH AX PUSH BX PUSH CX PUSH DX MOV AH, 6 ;Choose subfunction MOV AL, 0 ;Load parameters MOV BH, 7 MOV CX, DX MOV DL, 79 INT 10H ;Erase block POP DX POP CX POP BX POP AX RET ERASE_EOL ENDP ;=============================================================================== ; ; IDENTIFY Subroutine: ; ; Sends remote computer identifying string unique to VT52: esc / Z ; ;=============================================================================== IDENTIFY PROC NEAR PUSH AX PUSH DI LEA DI, TQ MOV AL, ESCAPE ;Send esc CALL ENQUEUE MOV AL, "/" ;Send / CALL ENQUEUE MOV AL, "Z" ;Send Z CALL ENQUEUE POP DI POP AX RET IDENTIFY ENDP ;=============================================================================== ; ; LINE_SETTINGS Subroutine: ; ; Allows user to alter communication parameters. UART is reset, ; and status line updated. ; ;=============================================================================== LINE_SETTINGS PROC NEAR PUSH AX PUSH BX PUSH DX MOV DX, 1800H ;Prompt user for BAUD LOCATE DISPLAY BAUD_PROMPT LS1: MOV AH, 8 INT 21H ;Get response CMP AL, 97 JB CAPS SUB AL, 32 CAPS: SUB AL, 65 CMP AL, 7 JA LS1 MOV BH, 0 MOV BL, AL SHL BL, 1 MOV DX, BAUD[BX] BIN2ASCII 4, STATUS[17] ;Update status line SHL AL, 1 ;Update parameters for UART SHL AL, 1 SHL AL, 1 SHL AL, 1 SHL AL, 1 MOV COMM_PAR, AL MOV DX, 1800H ;Prompt user for PARITY LOCATE DISPLAY PARITY_PROMPT LS2: MOV AH, 8 ;get response INT 21H CMP AL, 97 ;Interpret choice JB CAPS2 SUB AL, 32 CAPS2: CMP AL, "E" JE LS3 CMP AL, "O" JE LS4 CMP AL, "N" JE LS5 JMP LS2 LS3: OR COMM_PAR, 00011000B ;Update UART parameters LS4: OR COMM_PAR, 00001000B LS5: MOV STATUS[33], AL MOV DX, 1800H ;Prompt user for data bits LOCATE DISPLAY DATA_PROMPT LS6: MOV AH, 8 ;Get response INT 21H CMP AL, "8" JE LS7 CMP AL, "7" JE LS8 JMP LS6 LS7: OR COMM_PAR, 11B LS8: OR COMM_PAR, 10B MOV STATUS[49], AL MOV DX, 1800H ;Prompt user for stop bits LOCATE DISPLAY STOP_PROMPT LS9: MOV AH, 8 INT 21H ;Get response CMP AL, "2" JE LS10 CMP AL, "1" JE LS11 JMP LS9 LS10: OR COMM_PAR, 100B LS11: MOV STATUS[67], AL MOV DX, 1800H ;Display new status LOCATE DISPLAY STATUS MOV DX, VT_POSITION LOCATE CALL PORT_INIT ;Reinitialize UART POP DX POP BX POP AX RET LINE_SETTINGS ENDP BAUD DW 110, 150, 300, 600, 1200, 2400, 4800, 9600 ;=============================================================================== ; ; FLOW_CONTROL Subroutine: ; ; Implementation of XON/XOFF protocol. ; ; If XOFF received, informs user and waits for receipt of XON ; before further transmission. ; ;=============================================================================== FLOW_CONTROL PROC NEAR PUSH DX CMP FLOW, 0 ;XOFF received? JE FC_DONE MOV DX, 1800H LOCATE DISPLAY XOFF_MSG ;Inform user of receipt FC1: CMP FLOW, 0FFH ;Wait for XON JE FC1 LOCATE ;Refresh status line DISPLAY STATUS FC_DONE: POP DX RET FLOW_CONTROL ENDP ;=============================================================================== ; ; CHAT_SCREEN Subroutine: ; ; Displays windows for transmission and reception of characters. ; ; Uses the DISPLAY macro to display border elements, the LOCATE macro to ; position cursor, and the SCROLL_UP macro to clear the screen. ; ;=============================================================================== CHAT_SCREEN PROC NEAR PUSH CX PUSH DX SCROLL_UP 0, 0, 0, 24, 79 ;Blank screen initially MOV DX, 0 LOCATE ;Position top border DISPLAY TOP_BORDER MOV DH, 23 ;Position bottom border LOCATE DISPLAY BOT_BORDER MOV CX, 22 ;Draw vertical borders down 22 rows ROW: MOV DH, CL MOV DL, 0 LOCATE DISPLAY VERT_BORDER MOV DL, 39 LOCATE DISPLAY VERT_BORDER MOV DL, 40 LOCATE DISPLAY VERT_BORDER MOV DL, 79 LOCATE DISPLAY VERT_BORDER LOOP ROW MOV DX, 1800H ;Greet user LOCATE DISPLAY INTRO MOV TX_POSITION, 0101H MOV RX_POSITION, 0129H MOV DX, 0101H LOCATE POP DX POP CX RET CHAT_SCREEN ENDP ;=============================================================================== ; ; CHAT_INPUT Subroutine: ; ; Uses BIOS function INT 16h to check for and retrieve characters typed ; on transmitting keyboard. ; ; Output: AL = character typed, or 0 for invalid character ; AH DESTROYED ; ;=============================================================================== CHAT_INPUT PROC NEAR PUSH DX PUSH DI MOV AH, 1 INT 16H JZ DONE_IN SCROLL_UP 0, 24, 0, 24, 79 ;Clear status line MOV AH, 0 ;Accept character from keyboard INT 16H CMP AL, ESCAPE ;Exit for ESC JE DONE_IN CMP AL, 0 ;Convert cursor keys, and flag invalid keys JNE CHAR_ENQ CALL CURSOR_KEY CMP AL, 0 ;Don't enqueue invalid characters JE DONE_IN CHAR_ENQ: CMP AL, 9 ;Convert tabs to spaces JNE DETABBED MOV AL, 32 DETABBED: LEA DI, TQ ;Enqueue character for transmission CALL ENQUEUE JC QUEUE_ERROR ;Alert user of full queue CMP AL, EOM JNE TX_SHOW PUSH AX MOV AL, 11B MOV DX, 03F9H OUT DX, AL POP AX TX_SHOW: CALL TX_DISPLAY ;Display characters DONE_IN: POP DI POP DX RET QUEUE_ERROR: ;Display warning and instruction to user MOV DX, 1800H LOCATE DISPLAY FULL_QUEUE JMP DONE_IN CHAT_INPUT ENDP ;=============================================================================== ; ; CURSOR_KEY Subroutine: ; ; Converts cursor-movement-key scan codes into unused ASCII values ; for display and transmission. Also alerts user of invalid key ; entries. Uses DISPLAY and LOCATE macros to display message. ; ; Input: AH = scan code to be converted. ; ; Output: AL = ASCII value ; ;=============================================================================== CURSOR_KEY PROC NEAR CMP AH, 72 ;Up arrow? JE UP_TX CMP AH, 75 ;Left arrow? JE LEFT_TX CMP AH, 77 ;Right arrow? JE RIGHT_TX CMP AH, 80 ;Down arrow? JE DOWN_TX MOV AL, 0 MOV DX, 1800H LOCATE DISPLAY INVALID_MSG ;All other special keys are invalid RET UP_TX: MOV AL, 30 ;Convert cursor keys to RET ;unused ASCII values LEFT_TX: MOV AL, 29 RET RIGHT_TX: MOV AL, 28 RET DOWN_TX: MOV AL, 31 RET CURSOR_KEY ENDP ;=============================================================================== ; ; TX_DISPLAY Subroutine: ; ; Displays characters typed into keyboard for transmission. Uses DOS ; function 2, as well as LOCATE and SCROLL_UP macros for display. ; BIOS INT 10, subfunction 3 used to determine cursor location. ; ;=============================================================================== TX_DISPLAY PROC NEAR PUSH AX PUSH BX PUSH CX PUSH DX MOV DX, TX_POSITION ;Position cursor properly in OUT window ;Interpret cursor movement keys CMP AL, 8 ;Backspace? JE TD_LEFT CMP AL, 29 ;Left arrow? JNE TD_NL TD_LEFT: CMP DL, 1 JE TD_STEP DEC DL LOCATE JMP TD_SAVE TD_NL: CMP AL, 28 ;Right arrow? JNE TD_NR CMP DL, 38 JE TD_STEP INC DL LOCATE JMP TD_SAVE TD_NR: CMP AL, 30 ;Up arrow? JNE TD_NU CMP DH, 1 JE TD_STEP DEC DH LOCATE JMP TD_SAVE TD_STEP: LOCATE ;Used to facilitate long range, conditional jumps JMP TD_DONE TD_NU: CMP AL, 31 ;Down arrow? JNE TD_ND TD_DOWN: CMP DH, 22 JE TD_BOTTOM INC DH LOCATE JMP TD_SAVE TD_BOTTOM: SCROLL_UP 1, 1, 1, 22, 38 ;Scroll window 1 line if neccessary LOCATE JMP TD_DONE TD_ND: CMP AL, CR ;Carriage return? JNE TD_NC MOV DL, 1 JMP TD_DOWN TD_NC: CMP AL, LF ;Line feed? (interpret same as down arrow) JE TD_DOWN CMP AL, 0BH ;Vertical tab? (same as down arrow) JE TD_DOWN CMP AL, 0CH ;Form feed? (same as down arrow) JE TD_DOWN ;Display non-movement characters CMP DL, 39 ;Character on right edge of window? JNE TD_SHOW MOV DL, 1 ;Wrap around to next line CMP DH, 22 JNE TD_LINE SCROLL_UP 1, 1, 1, 22, 38 ;Scroll 1 line if neccessary JMP TD_SHOW TD_LINE: INC DH ;Move down a line TD_SHOW: LOCATE MOV AH, 2 MOV DL, AL INT 21H ;Display Character MOV AH, 3 MOV BH, 0 INT 10H ;Determine location of cursor TD_SAVE: MOV TX_POSITION, DX ;Store current location TD_DONE: POP DX POP CX POP BX POP AX RET TX_DISPLAY ENDP ;=============================================================================== ; ; RX_DISPLAY Subroutine: ; ; Displays any messages received from serial port. Uses DOS ; function 2, as well as LOCATE and SCROLL_UP macros for display. ; BIOS INT 10, subfunction 3 used to determine cursor location. ; ;=============================================================================== RX_DISPLAY PROC NEAR PUSH AX PUSH BX PUSH CX PUSH DX PUSH DI CMP RQ.NMSGS, 0 ;Pending messages for display? JNE DEQUIT JMP RD_DONE DEQUIT: LEA DI, RQ ;Dequeue next available character CALL DEQUEUE MOV DX, RX_POSITION ;Position cursor properly in window ;Interpret cursor movement keys CMP AL, 8 ;Backspace? JE RD_LEFT CMP AL, 29 ;Left arrow? JNE RD_NL RD_LEFT: CMP DL, 41 JE RD_STEP DEC DL LOCATE JMP RD_SAVE RD_NL: CMP AL, 28 ;Right arrow? JNE RD_NR CMP DL, 78 JE RD_STEP INC DL LOCATE JMP RD_SAVE RD_NR: CMP AL, 30 ;Up arrow? JNE RD_NU CMP DH, 1 JE RD_STEP DEC DH LOCATE JMP RD_SAVE RD_STEP: LOCATE ;Intermediate step for long range JMP RD_DONE ;conditional jump RD_NU: CMP AL, 31 ;Down arrow? JNE RD_ND RD_DOWN: CMP DH, 22 JE RD_BOTTOM INC DH LOCATE JMP RD_SAVE RD_BOTTOM: SCROLL_UP 1, 1, 41, 22, 78 ;Scroll 1 line if neccessary LOCATE JMP RD_DONE RD_ND: CMP AL, CR ;Carriage return? JNE RD_NC MOV DL, 41 JMP RD_DOWN RD_NC: CMP AL, LF ;Line feed? (Interpret like down arrow) JE RD_DOWN CMP AL, 0BH ;Vertical tab? (same as down arrow) JE RD_DOWN CMP AL, 0CH ;Form feed? (same as down arrow) JE RD_DOWN ;Display non-movement characters CMP DL, 79 ;Wrap line if neede JNE RD_SHOW MOV DL, 41 CMP DH, 22 JNE RD_LINE SCROLL_UP 1, 1, 41, 22, 78 ;Scroll 1 line if needed JMP RD_SHOW RD_LINE: INC DH ;Move down one line for wrap RD_SHOW: LOCATE ;Position cursor MOV AH, 2 MOV DL, AL INT 21H ;Display character MOV AH, 3 MOV BH, 0 INT 10H ;Determine current location of cursor RD_SAVE: MOV RX_POSITION, DX ;Store location RD_DONE: POP DI POP DX POP CX POP BX POP AX RET RX_DISPLAY ENDP ;=============================================================================== ; ; ENQUEUE Subroutine: ; ; Used to enqueue the character in AL into specified queue. ; ; Input: AL = character to be enqueued ; DI = pointer to queue ; ; Output: CF = 1 if attempted enqueue failed due to full queue ; CF = 0 otherwise ; [DI].REAR updated ; [DI].COUNT incremented if enqueue successful ; [DI].NMSGS incremented if character is EOM ; THRE interupts enabled if character is EOM ; ;=============================================================================== ENQUEUE PROC NEAR PUSH DX PUSH SI CMP DI, OFFSET RQ ;Don't check RQ for full queue JE ENQ1 CMP AL, EOM ;Don't check for full queue if EOM JNE TQ_NOT_EOM MOV LMSG, 0 JMP ENQ1 TQ_NOT_EOM: CMP LMSG, MSGCAP ;Check TQ for full queue STC ;Assume full queue JNE ENQ0 JMP DONE_ENQ ENQ0: INC LMSG ;Increment current msg length for TQ ENQ1: MOV SI, [DI].REAR ;Adjust the rear pointer CMP SI, [DI].QBEG JA ENQ2 ADD SI, QCAPAC ENQ2: DEC SI MOV [DI].REAR, SI MOV [SI], AL ;Enque the character INC [DI].COUNT ;Update queue count CMP AL, EOM CLC JNE DONE_ENQ INC [DI].NMSGS ;If EOM, increment pending messages DONE_ENQ: POP SI POP DX RET ENQUEUE ENDP ;=============================================================================== ; ; DEQUEUE Subroutine: ; ; Used to dequeue a character into AL from specified queue. ; ; Input: DI = pointer to queue ; ; Output: AL = character dequeued ; [DI].FRONT updated ; [DI].COUNT decremented ; [DI].NMSGS decremented if character = EOM ; ;=============================================================================== DEQUEUE PROC NEAR PUSH DX PUSH SI DEC [DI].COUNT ;Update queue counter MOV SI, [DI].FRONT ;Adjust the front pointer CMP SI, [DI].QBEG JA DEQ1 ADD SI, QCAPAC DEQ1: DEC SI MOV [DI].FRONT, SI MOV AL, [SI] ;Dequeue the character CMP AL, EOM ;Check for end of message JNE DEQ2 DEC [DI].NMSGS DEQ2: POP SI POP DX RET DEQUEUE ENDP ;=============================================================================== ; ; CLEAR_QUEUES Subroutine: ; ; Wipes transmit and receive queues clear for switching modes. ; ;=============================================================================== CLEAR_QUEUES PROC NEAR PUSH AX MOV AX, RQ.QBEG ;Reinitialize receive queue ADD AX, QCAPAC MOV RQ.FRONT, AX MOV RQ.REAR, AX MOV RQ.COUNT, 0 MOV RQ.NMSGS, 0 MOV AX, TQ.QBEG ;Reinitialize transmit queue ADD AX, QCAPAC MOV TQ.FRONT, AX MOV TQ.REAR, AX MOV TQ.COUNT, 0 MOV TQ.NMSGS, 0 POP AX RET CLEAR_QUEUES ENDP ;=============================================================================== ; ; Queue Structures: ; ; TQ is used to hold up to 512 characters before transmission. ; RQ is used to hold up to 512 characters, after reception, but ; before display. ; ;=============================================================================== QSTRUC STRUC FRONT DW ? ;Ptr to last character dequeued REAR DW ? ;Ptr to last character enqueued QBEG DW ? ;Offset of first byte of queue COUNT DW ? ;Number of bytes currently in queue NMSGS DW ? ;Number of messages pending QSTRUC ENDS QCAPAC EQU 512 TQBEG DB QCAPAC DUP('T') ;Allocate space for queues RQBEG DB QCAPAC DUP('R') ;Initialize queues TQ QSTRUC <TQBEG+QCAPAC, TQBEG+QCAPAC, TQBEG, 0, 0> RQ QSTRUC <RQBEG+QCAPAC, RQBEG+QCAPAC, RQBEG, 0, 0> CSEG ENDS END MAIN