QRZ! Ham Radio 9

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/ QRZ! Ham Radio 9 / QRZ Ham Radio Callsign Database - Volume 9.iso / pc / files / pbbs / iosc51.arc / BR1BIOS.ASM next >

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Assembly Source File | 1988-02-15 | 18.6 KB | 657 lines

PAGE 60,132 TITLE BR1BIOS - Serial interface for COM1 ;Interupt driven RS232 serial port routines. ; these routines replace the BIOS rs232 calls with a version that has ; interupt driven character receive, and can thus operate at considerably ; higher speeds than the standard bios calls (int 14h). ; Added break function (7). ; Set up the works everything SEGMENT PUBLIC ASSUME CS: everything ; These assumptions are for the ASSUME DS: everything ; assembler's benefit. The code ASSUME ES: nothing ; jerks things around as it pleases ASSUME SS: nothing ; Program start and buffer declares ORG 100H foo: jmp start ; Entry point org 0 ; Back up so we can use this all as ; buffer space ; Area where things are declared include constbios.asm dummy: ; Dummy labels to provide a structure i_buf db buffer_size dup(?) ; Buffer (1 per com card) i_buf_e: ; End of buffer comnumber db ? ; Comm number - 1 flags db ? ; Flag byte last_rs db ? ; Last receive status hiv db ? ; Hardware interrupt vector int_mask db ? ; Mask for 8259 baseaddr dw ? ; Base port address i_count dw ? ; # of chars in buffer i_buf_in dw ? ; Buffer in pointer i_buf_out dw ? ; Buffer out pointer dummy_end: org dummy ; Back up over this ; These are the things to work with db buffer_size dup(?) ; Buffer (1 per com card) db 0 ; Com number db 0 ; Flags db 0 ; Last receive status db 0ch ; Hardware interrupt vector db 0efh ; Mask dw 03f8h ; Base port address dw 0 ; # of chars in buffer dw ? ; Buffer in pointer dw ? ; Buffer out pointer comend: ; Marker for last com port ; Static variables old_bios_vector dw ? ; Save previous interrupt vector dw ? divisor_table LABEL WORD dw 1047 ; 110 dw 768 ; 150 dw 384 ; 300 dw 192 ; 600 dw 96 ; 1200 dw 48 ; 2400 dw 24 ; 4800 dw 12 ; 9600 ; Our BIOS handler rsint: ASSUME DS: NOTHING ; Don't use DS ASSUME ES: NOTHING ; Don't use ES ASSUME SS: NOTHING ; Don't use SS ; Not disabled please sti ; See if this is our vector? push bp ; Save BP over our loop xor bp,bp cmp dl,cs:comnumber[bp] ; Is this our port? je rsint_ours ; Yes... ; Not us.. Pop things out and call regular handler pop bp jmp cs:dword ptr old_bios_vector ; BP now contains the pointer to the com block... See what ; the user has requested and we may or may not do it....... rsint_ours: push dx ; We need the DX register push cx ; We need the CX register push bx ; We need the BX register mov cx,baseaddr[bp] ; Get base address for chip or ah,ah ; Initialize? je rsint_init ; Yes... dec ah ; 1 = Send character jz rsint_send dec ah ; 2 = Receive character jz rsint_recv_jmp dec ah ; 3 = Status request jz rsint_status_jmp dec ah ; 4 = Inquiry jz rsint_inquiry_jmp dec ah dec ah dec ah jz rsint_break_jmp ; 7 = send break jmp rsint_exit ; Nope.. rsint_recv_jmp: jmp rsint_recv rsint_status_jmp: jmp rsint_status rsint_inquiry_jmp: jmp rsint_inquiry rsint_break_jmp: jmp rsint_break ; Interrupt exit rsint_exit: pop bx ; Restore registers pop cx pop dx pop bp iret ; and leave ; Init.. rsint_init: mov ah,al ; Save the parms for later mov bl,ah ; Look up the baud rate mov cl,4 ; parameter rol bl,cl and bx,0eh mov bx,divisor_table[bx] mov cx,baseaddr[bp] ; Get base address for chip mov dx,cx ; Address of LCR add dx,lcr_8250 mov al,10000000B ; Enable access to divisor out dx,al mov dx,cx ; Address of lower divisior half add dx,dll_8250 mov al,bl ; Put lower half out dx,al mov dx,cx ; Address of upper divisior half add dx,dlm_8250 mov al,bh ; Put upper half out dx,al mov al,ah ; Get parms back and al,1fh ; Throw away baud rate mov dx,cx ; Address of LCR add dx,lcr_8250 out dx,al ; Output the parms ; Turn on the port mov dx,cx ; Compute port address for the MCR add dx,mcr_8250 mov al,00001011B ; Raise DTR, RTS & OUT2 out dx,al ; OUT2 turns on interrupts jmp rsint_status ; Now just status please ; Send a character rsint_send: mov ah,al ; Save the character to send rsint_send_loop: ; Loop here until we can send mov dx,cx ; Compute port address for the MSR add dx,msr_8250 ; and then in al,dx ; get it into AX and al,10h ; CTS jz rsint_send_loop mov dx,cx ; Compute port address for the LSR add dx,lsr_8250 ; and then in al,dx ; get itinto AX and al,20h ; THR empty? jz rsint_send_loop ; No.. Loop back mov al,ah ; Get ready to out character mov dx,cx ; Compute port address for the THR ; add dx,thr_8250 ; and then out dx,al ; out the character jmp rsint_status ; Do a status ; Receive a character rsint_recv: MOV BX,i_buf_out[BP] ; Get buffer output pointer rsint_recv_loop: CMP i_count[BP],0 ; Anything in buffer? JE rsint_recv_loop ; No, Wait for it rsint_get_char: MOV AL,CS:[BX] ; Get character from buffer PUSH AX ; Save char INC BX ; Bump pointer DEC i_count[BP] ; Dec char count MOV DX,OFFSET i_buf_e ; Compute end of buffer ADD DX,BP CMP BX,DX ; Have we wrapped the buffer? JL test_handshake ; No.. All done MOV BX,OFFSET i_buf ; Yes.. Reset pointer ADD BX,BP test_handshake: cmp i_count[BP],80H jnb test_full mov ah,flags[BP] test ah,1 ; Did we RTS off? jz test_full ; No, so don't RTS on roll_hands: mov DX,CX add DX,mcr_8250 in AL,DX or AL,00001011B ; Raise DTR, RTS & OUT2 out DX,AL and AH,0FEH ; Remember RTS is on mov flags[BP],AH test_full: POP AX ; Restore Char MOV i_buf_out[BP],BX ; Save pointer MOV AH,last_rs[BP] ; Get last LSR from receive AND AH,0FEH ; Remove data ready bit CMP i_count[BP],0 ; Anything left in buffer? JE short_exit ; Nope so leave OR AH,1 ; Turn on data ready short_exit: JMP rsint_exit ; and go leave ; Status.. rsint_status: MOV DX,CX ; Compute port address for the LSR ADD DX,lsr_8250 ; and then IN AL,DX ; get it AND AL,0FEH ; Remove data ready bit CMP i_count[BP],0 ; Anything left in buffer? JE rsint_status_nodr ; Nope so leave OR AL,1 ; Turn on data ready rsint_status_nodr: MOV AH,AL ; Save LSR MOV DX,CX ; Compute port address for the MSR ADD DX,msr_8250 ; and then IN AL,DX ; get it JMP rsint_exit ; All done ; Inquiry ; (Return AA55H in AX - Just an identification scheme to tell ; if this silly driver has been loaded) rsint_inquiry: MOV AX,0AA55H JMP rsint_exit ; and go leave ; send break rsint_break: mov dx,cx add dx,lcr_8250 in al,dx mov bl,al mov al,40h out dx,al mov cx,0 bkwait: loop bkwait mov al,bl out dx,al jmp rsint_exit ; 8250 interrupt handler serint_8250: PUSH BP PUSH DX PUSH AX PUSH CX ; Save some registers PUSH DI xor bp,bp MOV CX,baseaddr[BP] ; Get base address for chip MOV DX,CX ; Get the IIR ADD DX,iir_8250 IN AL,DX TEST AL,1 ; Interrupt pending? JZ service JMP serint_8250_exit ; No leave... service: MOV DX,CX ; Get the LSR ADD DX,lsr_8250 IN AL,DX MOV last_rs[BP],AL ; And tuck it away MOV DX,CX ; Get the RBR ; ADD DX,rbr_8250 IN AL,DX MOV DI,i_buf_in[BP] ; Get the buffer pointer MOV CS:[DI],AL ; Save the character INC DI ; Bump pointer and handle wrap MOV AX,OFFSET i_buf_e ADD AX,BP CMP DI,AX JL nowrap MOV DI,OFFSET i_buf ADD DI,BP nowrap: cmp i_count[BP],buffer_full jb hand_done mov DX,CX add DX,mcr_8250 in al,DX and AL,11111100B ; Drop DTR & RTS out DX,AL mov ah,flags[BP] or AH,1 ; Remember RTS is off mov flags[BP],AH hand_done: CMP DI,i_buf_out[BP] ; Overflow of buffer? JNE noover OR last_rs[BP],2 ; Overrun indicate JMP SHORT serint_8250_exit ; Don't save the updated pointer noover: MOV i_buf_in[BP],DI ; Save the updated pointer inc i_count[BP] ; inc char count serint_8250_exit: MOV AL,20H ; Tell 8259 we are done OUT pic_cmd_port,AL POP DI ; Restore registers POP CX POP AX POP DX POP BP IRET ; Exit program_end: ; Main line to initialize. ASSUME DS: everything ; Constants only needed by initialization P3F8 DB 0 ;1 IF CARD AT 3F8 P2F8 DB 0 ;1 IF CARD AT 2F8 HELLO DB CR,LF DB 'COM1BIOS Driver v1.5',CR,LF DB 'Dec 18, 1986 ' DB CR,LF,'$' BYE DB CR,LF DB 'Driver Installed OK!' DB CR,LF,'$' LOADED DB CR,LF DB 'COM1BIOS already loaded!' DB CR,LF,'$' COM1F DB CR,LF DB 'COM1: board found at 03F8',CR,LF DB '$' COM2F DB CR,LF DB 'COM2: board found at 02F8',CR,LF DB '$' NOCOM DB CR,LF DB 'COM1: board not found.' DB CR,LF DB 'Driver NOT installed!',CR,LF DB '$' ; INITIALIZE ROUTINE start: MOV AX,CS ; Point DS in the right place MOV DS,AX CALL SINON ;PRINT SIGN ON MOV DX,00 ;Check to see if support already loaded MOV AH,04 INT 14H CMP AX,0AA55H JZ EXIT ;Must be loaded CALL CNFIG ;CHECK CONFIGURATION OR AX,AX JNZ EREXIT ;JMP IF ERRORS CALL init_vectors ;SET INTERRUPT VECTORS CALL SINOFF ;PRINT SIGN OFF MOV AL,0 ;set exit code MOV DX,OFFSET program_end MOV CL,4 SHR DX,CL INC DX MOV AH,31H INT 21H ; Terminate but stay resident EREXIT: MOV AL,1 ;set exit code = Error MOV AH,4CH INT 21H ; Terminate and return EXIT: LEA DX,LOADED MOV AH,9 INT 21H MOV AL,0 ;set exit code = Ok MOV AH,4CH INT 21H ; Terminate and return ;--------- CNFIG: CALL FNDPT ;Find Ports CMP P3F8,1 JNE CNF1 LEA DX,COM1F ;Say COM1 Found MOV AH,9 INT 21H CNF1: CMP P2F8,1 JNE CNF2 LEA DX,COM2F ;Say COM2 Found MOV AH,9 INT 21H CNF2: CMP P3F8,1 JE CNF3 LEA DX,NOCOM ;Say OOPS MOV AH,9 INT 21H CNFERR: MOV AX,0FFFFH ;Set Error RET CNF3: SUB AX,AX RET ;------------ FNDPT: MOV DX,03F8H CALL CKPORT CMP BP,0 JZ PT2 INC P3F8 PT2: MOV DX,02F8H CALL CKPORT CMP BP,0 JZ PT3 INC P2F8 PT3: RET ; Check for valid Port ; Enter with DX containing Port address ; Exit with BP=Port address if port found BP=0 if not found CKPORT: MOV BP,DX ;For return MOV CL,DL ;Keep DL Handy ADD DX,3 IN AL,DX ;Save old LCR in CH MOV CH,AL MOV AL,80H ;Address Divisor Latch OUT DX,AL CALL WAIT MOV DL,CL IN AL,DX MOV AH,AL ;Save old Divisor CALL WAIT INC DX IN AL,DX ;Save old Divisor MOV BX,AX CALL WAIT MOV DL,CL MOV AL,55H ;OUTPUT 55 OUT DX,AL CALL WAIT INC DX MOV AL,0AAH OUT DX,AL ;OUTPUT AA CALL WAIT MOV DL,CL IN AL,DX ;Read New Divisor MOV AH,AL CALL WAIT INC DX IN AL,DX CMP AX,55AAH ;DO THEY MATCH? JZ Match XOR BP,BP ;Zero - no match Match: MOV DL,CL MOV AL,BH ;Restore old Divisor OUT DX,AL CALL WAIT INC DX MOV AL,BL OUT DX,AL CALL WAIT INC DX INC DX ;and old LCR MOV AL,CH OUT DX,AL CALL WAIT WAIT: RET ;--------- ;PRINT SIGNON SINON: LEA DX,HELLO MOV AH,9 INT 21H RET ;PRINT SIGNOFF SINOFF: LEA DX,BYE MOV AH,9 INT 21H RET ; Now snatch the BIOS comm vector (Int 14) init_vectors: MOV AL,14H MOV AH,35H INT 21H MOV old_bios_vector,BX ; save old vector MOV old_bios_vector+2,ES MOV DX,OFFSET rsint ; Replace with our vector MOV AL,14H MOV AH,25H INT 21H ; Set the hardware interrupt vector XOR bp,bp ; Get a zero MOV DX,OFFSET serint_8250 ; Get our address MOV AL,hiv[BP] MOV AH,25H INT 21H ; Initialize the buffer ring pointers MOV AX,OFFSET i_buf ; Get start of buffer address ADD AX,BP ; include our offset MOV i_buf_in[BP],AX ; Put in the buffer pointers MOV i_buf_out[BP],AX ; Put in the buffer pointers ; Set the interrupt registers in the UART and clean things up CLI ; Disable interrupts IN AL,pic_mask_port ; Set up 8259 interupt controller AND AL,int_mask[BP] ; Enable the interrupts for this device OUT pic_mask_port,AL MOV CX,baseaddr[BP] ; Get base address for chip MOV DX,CX ; Compute port address for the IER ADD DX,ier_8250 MOV AL,1 ; Enable data interrupt only OUT DX,AL MOV DX,CX ; Compute port address for the RBR ADD DX,rbr_8250 IN AL,DX ; Read the input buffer and throw it away ; Enable interrupts STI ; Enable CPU to receive interupts RET everything ENDS END foo