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Assembly Source File | 1987-09-17 | 30.9 KB | 645 lines

; revised by rwt for dual-display systems, tests display type each time ; the window is activated. Done through calls to set-display-type, which ; is a re-written portion of the initialization routine. Also eliminated ; possibility of entering ASCII 127 (in SCR_TABLE). ; ; All changes to the program are in UPPER-case letters. Un-commented ; portions are closely related to the original, commented out but ; commented, source code. This should work with any normal two display ; system, e.g. mono with either cga or ega. ; ;KBX.COM for the IBM Personal Computer - 1987 by Jeff Prosise ; kb_data equ 60h ;keyboard data port kb_ctrl equ 61h ;keyboard control port eoi equ 20h ;8259 EOI value int_ctrl equ 20h ;8259 port address ; bios_data segment at 40h ;BIOS data area org 17h kb_status db ? ;keyboard status byte org 1Ah buffer_head dw ? ;pointer to keyboard buffer head buffer_tail dw ? ;pointer to keyboard buffer tail org 80h buffer_start dw ? ;starting keyboard buffer address buffer_end dw ? ;ending keyboard buffer address bios_data ends ; code segment para public 'code' ;code segment assume cs:code org 100h begin: jmp initialize ;goto initialization code ; copyright db 'Copyright 1987 Ziff-Davis Publishing Co.',1Ah enable_values db 2Ch,28h,2Dh,29h,2Ah,2Eh,1Eh screen_buffer dw offset initialize ;pointer to screen buffer aux_shift db 0 ;auxiliary keyboard status byte old_shift db 0 ;storage for shift status window_status db 0 ;window display status adapter db 2 ;0 = MDA, 1 = CGA, 2 = EGA video_segment dw 0B800h ;default video segment border_attr db 2Fh ;window border attribute text_attr db 1Bh ;window border attribute cursor_mode dw 0607h ;default cursor shape cursor_position dw ? ;saved cursor position video_page db ? ;saved video page number video_offset dw ? ;starting window offset address addr_6845 dw ? ;port address of CRTC ibm db 'IBM' ;EGA ASCII signature old9h label dword old9h_vector dw 2 dup (?) ;storage for interrupt 9 vector ; fill_parms dw 1,030Fh,12 dw 2,050Fh,12 dw 2,070Fh,12 dw 2,090Fh,10 dw 17,0537h,4 dw 0,0737h,4 dw 0,0937h,3 ; def_table db 0,'1234567890-=',0 db 0,'QWERTYUIOP[]',0 db 0,'ASDFGHJKL;',39,96 db 0,0,'ZXCVBNM,./' db 17 dup (0) db '789-456+123',0,0 ; scr_table db 0,000,128,129,130,131,132,133,134,135,136,137,138,0 ; NOTE 127 ABOVE CHANGED TO 000 db 0,139,140,141,142,143,144,145,146,147,148,149,150,0 db 0,151,152,153,154,155,156,157,158,159,160,161,162 db 0,0,163,164,165,166,167,168,0,0,0,0 db 17 dup (0) db 201,203,187,205,204,206,185,186,200,202,188,0,0 ; num_table db 0,169,170,171,172,173,174,175,176,177,178,219,220,0 db 0,221,222,223,224,225,226,227,228,229,230,231,232,0 db 0,233,234,235,236,237,238,239,240,241,242,243,244 db 0,0,245,246,247,248,249,250,251,252,253,254 db 17 dup (0) db 218,194,191,196,195,197,180,179,192,193,217,0,0 ; ;------------------------------------------------------------------------------ ;Interrupt 9 handler. Execution comes here when a key is pressed or released. ;------------------------------------------------------------------------------ new9h proc near sti ;set interrupt enable flag push ax ;save AX in al,kb_data ;get scan code from keyboard cmp al,69 ;NumLock key pressed? je numlock_down ;yes, then branch cmp al,69+128 ;NumLock key released? je numlock_up ;yes, then branch cmp al,70 ;ScrLock key pressed? je scrlock_down ;yes, then branch cmp al,70+128 ;ScrLock key released? je scrlock_up ;yes, then branch cmp al,57 ;spacebar pressed? je spacebar ;yes, then branch cmp aux_shift,0 ;NumLock or ScrLock depressed? je exit ;no, then exit jmp newkey ;yes, then branch exit: pop ax ;restore AX jmp old9h ;goto old interrupt handler ; ;The NumLock key was pressed. Toggle NumLock state or set shift bit. ; numlock_down: call get_status ;get main shift status byte test al,12 ;is either Ctrl or Alt pressed? jnz exit ;yes, then goto normal handler push ax ;save shift code call reset_kb ;reset the keyboard pop ax ;retrieve shift code test al,3 ;is either Shift key depressed? jnz numlock1 ;yes, then branch or aux_shift,2 ;set NumLock shift bit jmp end_int ;exit numlock1: push ds ;save DS mov ax,bios_data ;point DS to BIOS data area mov ds,ax assume ds:bios_data xor kb_status,32 ;toggle NumLock state pop ds ;restore DS assume ds:nothing jmp end_int ;exit ; ;The NumLock key was released. Clear the NumLock shift bit. ; numlock_up: call reset_kb ;reset the keyboard and aux_shift,253 ;clear shift bit jmp end_int ;exit ; ;The ScrLock key was pressed. Toggle ScrLock state or set shift bit. ; scrlock_down: call get_status ;get main shift status byte test al,12 ;is either Ctrl or Alt pressed? jnz exit ;yes, then goto normal handler push ax ;save shift code call reset_kb ;reset the keyboard pop ax ;retrieve shift code test al,3 ;is either Shift key depressed? jnz scrlock1 ;yes, then branch or aux_shift,1 ;set ScrLock shift bit jmp end_int ;exit scrlock1: push ds ;save DS mov ax,bios_data ;point DS to BIOS data area mov ds,ax assume ds:bios_data xor kb_status,16 ;toggle ScrLock state pop ds ;restore DS assume ds:nothing jmp end_int ;exit ; ;The ScrLock key was released. Clear the ScrLock shift bit. ; scrlock_up: call reset_kb ;reset the keyboard and aux_shift,254 ;clear shift bit end_int: mov al,eoi ;issue EOI to 8259 controller out int_ctrl,al pop ax ;clean up the stack iret ;return from interrupt ; ;The spacebar was pressed. Pop up the window if Alt is depressed. ; spacebar: call get_status ;get current shift status test al,8 ;is the Alt key depressed? jz exit ;no, then exit to normal handler call reset_kb ;yes, then reset keyboard mov al,eoi ;issue end-of-interrupt signal out int_ctrl,al cmp window_status,0 ;is the window already up? jne space1 ;yes, then ignore keypress push bx ;save BX call kb_display ;pop up keyboard display pop bx ;restore BX space1: pop ax ;clean up the stack iret ;exit ; ;A key was pressed or released with NumLock or ScrLock held down. ; newkey: push ax ;save scan code call reset_kb ;reset keyboard pop ax ;recover scan code test al,80h ;is the high bit set? jnz newkey3 ;yes, then don't process it push bx ;save BX mov bx,offset num_table ;point BX to NumLock key table cmp aux_shift,1 ;ScrLock depressed? jne newkey1 ;no, then continue mov bx,offset scr_table ;yes, then adjust BX newkey1: mov ah,al ;transfer scan code to AH dec al ;set AL relative to zero base xlat num_table ;get ASCII code from table or al,al ;is it zero? je newkey2 ;yes, then don't process this key call insert_char ;insert character into kb buffer newkey2: pop bx ;restore BX register value newkey3: mov al,eoi ;issue end-of-interrupt signal out int_ctrl,al pop ax ;restore AX and clean up the stack iret new9h endp ; ;------------------------------------------------------------------------------ ;RESET_KB resets the keyboard. ;------------------------------------------------------------------------------ reset_kb proc near in al,kb_ctrl ;get control port value mov ah,al ;save it or al,80h ;set high bit of control value out kb_ctrl,al ;send reset value mov al,ah ;get original control value out kb_ctrl,al ;enable keyboard ret ;done reset_kb endp ; ;------------------------------------------------------------------------------ ;GET_STATUS returns the main keyboard shift status byte in AL. ;------------------------------------------------------------------------------ get_status proc near push ds ;save DS mov ax,bios_data ;point DS to BIOS data area mov ds,ax assume ds:bios_data mov al,kb_status ;get status byte in AL pop ds ;restore DS assume ds:nothing ret ;exit get_status endp ; ;------------------------------------------------------------------------------ ;INSERT_CHAR inserts the character code in AX into the keyboard buffer. ;Entry: AH,AL - scan code, ASCII code ;------------------------------------------------------------------------------ insert_char proc near push dx ;save DX and DS push ds mov bx,bios_data ;point DS to BIOS data area mov ds,bx assume ds:bios_data mov bx,buffer_tail ;get current buffer tail address mov dx,bx ;transfer it to DX add dx,2 ;calculate next buffer position cmp dx,buffer_end ;did we overshoot the end? jne insert1 ;no, then continue mov dx,buffer_start ;yes, then wrap around insert1: cmp dx,buffer_head ;is the buffer full? je insert2 ;yes, then branch mov [bx],ax ;deposit character into buffer mov bx,dx ;advance buffer tail mov buffer_tail,bx ;record its new value insert2: pop ds ;restore DS assume ds:nothing pop dx ;restore DX ret ;exit insert_char endp ; ;------------------------------------------------------------------------------ ;KB_DISPLAY opens a window showing all possible key definitions. ;------------------------------------------------------------------------------ kb_display proc near ; ;Make sure current video mode is an 80-column text mode. ; mov ah,15 ;get current video mode int 10h cmp al,2 ;video mode 2? je kb1 ;yes, then continue cmp al,3 ;video mode 3? je kb1 ;yes, then continue cmp al,7 ;video mode 7 (monochrome)? je kb1 ret ;unsupported mode - terminate kb1: mov window_status,1 ;set status flag push cx ;save register values push dx push si push di push ds push es push cs ;set DS and ES to the code segment pop ds assume ds:code push cs ; pop es ;THIS POP MOVED DOWN 3 LINES ; ;Save page number, cursor mode, and cursor position. Then blank the cursor. ; mov video_page,bh ;store video page number CALL SET_DISPLAY_TYPE ; CHECK DISPLAY TYPE EACH TIME. POP ES ; SEE 3 LINES UP mov ah,3 ;get current cursor mode int 10h mov cursor_mode,cx ;store cursor mode call read_cursor ;get cursor position mov cursor_position,ax ;save it mov ah,1 ;hide the cursor mov ch,20h int 10h ; ;Save the portion of video memory that will be overwritten. ; cmp adapter,1 ;disable video if this is a CGA jne kb2 call disable_cga kb2: call save_screen ;copy video memory into buffer ; ;Open the keyboard display window. ; call open_window ;open the window cmp adapter,1 ;enable CGA video jne kb3 call enable_cga kb3: lea si,def_table ;point SI to default key table call fill_window ;draw unshifted key definitions ; ;The window is open. Loop until the ESC key is pressed, continually monitoring ;the auxiliary shift byte to determine what key definition set to display. ; kb4: mov ah,1 ;check buffer for character int 16h jz kb5 ;branch if buffer is empty mov ah,0 ;get the character int 16h cmp al,27 ;is it the ESC key? je kb7 ;yes, then close window and exit kb5: mov al,aux_shift ;get auxiliary shift byte cmp al,2 ;is it <= 2? jna kb6 ;yes, then branch mov al,2 ;no, then set it to 2 kb6: cmp al,old_shift ;has the shift status changed? je kb4 ;no, then loop back mov old_shift,al ;record current shift status mov bl,83 ;calculate table address from AL mul bl mov si,ax ;transfer it to SI add si,offset def_table ;complete offset address in SI call fill_window ;write key equivalents to window jmp kb4 ;go back for more ; ;The ESC key was pressed. Close the window and exit. ; kb7: cmp adapter,1 ;blank CGA video jne kb8 call disable_cga kb8: call restore_screen ;restore contents of video memory cmp adapter,1 ;enable CGA video jne kb9 call enable_cga kb9: mov ah,2 ;restore cursor position mov bh,video_page mov dx,cursor_position int 10h mov ah,1 ;unblank the cursor mov cx,cursor_mode int 10h mov window_status,0 ;reset status flag pop es ;restore register values pop ds pop di pop si pop dx pop cx ret ;return to calling routine kb_display endp ; ;------------------------------------------------------------------------------ ;SAVE_SCREEN saves the block of video memory that will be overwritten. ;------------------------------------------------------------------------------ save_screen proc near mov si,182 ;set zero page window offset in SI mov cl,video_page ;get video page in CX xor ch,ch jcxz save2 ;branch if page zero save1: add si,1000h ;add one page length loop save1 ;loop until offset is correct save2: mov video_offset,si ;save starting window address push ds ;save DS mov ds,video_segment ;point DS to video memory assume ds:nothing mov di,screen_buffer ;point ES:DI to screen buffer mov cx,11 ;11 lines to save save3: push cx ;save line counter mov cx,58 ;58 characters per line cld ;clear DF rep movsw ;transfer one line to storage pop cx ;retrieve counter add si,44 ;point SI to next line loop save3 ;loop until all lines are saved pop ds ;restore DS assume ds:code ret save_screen endp ; ;------------------------------------------------------------------------------ ;RESTORE_SCREEN restores saved video memory. ;------------------------------------------------------------------------------ restore_screen proc near mov es,video_segment ;point ES to video segment mov di,video_offset ;point DI to window area mov si,screen_buffer ;point DS:SI to screen buffer mov cx,11 ;11 lines to restore restore1: push cx ;save line count mov cx,58 ;58 characters per line rep movsw ;restore one line pop cx ;retrieve count add di,44 ;advance DI to next line loop restore1 ;loop until done ret restore_screen endp ; ;------------------------------------------------------------------------------ ;DISABLE_CGA and ENABLE_CGA control CGA video output. ;------------------------------------------------------------------------------ disable_cga proc near mov dx,3DAh ;Status Register port address disable1: in al,dx ;read status test al,8 ;vertical retrace active? jz disable1 ;no, then wait until it is sub dx,2 ;point DX to MSR mov al,25h ;load disable value out dx,al ;disable video ret disable_cga endp ; enable_cga proc near mov ah,15 ;get current video mode int 10h lea bx,enable_values ;point BX to table of values xlat enable_values ;get value to enable signal mov dx,3D8h ;MSR address out dx,al ;enable video output ret enable_cga endp ; ;------------------------------------------------------------------------------ ;READ_CURSOR reads the cursor position directly from the CRT Controller. ;Exit: AH,AL - row, column ;------------------------------------------------------------------------------ read_cursor proc near mov dx,addr_6845 ;get CRTC Address Register port mov al,14 ;specify register number out dx,al inc dx ;point DX to Data Register in al,dx ;read high byte of cursor address mov ah,al ;save it in AH dec dx ;point DX back to Address Register mov al,15 ;specify next register number out dx,al inc dx ;point DX to Data Register in al,dx ;read low byte of address and ax,07FFh ;strip page bits from address mov bl,80 ;divide by 80 div bl xchg ah,al ;swap AH and AL ret read_cursor endp ; ;------------------------------------------------------------------------------ ;OPEN_WINDOW writes the new window to video memory. ;------------------------------------------------------------------------------ open_window proc near mov es,video_segment ;point ES to video memory mov di,video_offset ;point DI to start of window mov al,218 ;get first character code mov ah,border_attr ;and first attribute byte stosw ;write mov cx,56 ;do the next 56 characters mov al,196 rep stosw mov al,191 ;finish the first line stosw add di,44 ;advance DI to next line mov cx,9 ;9 identical lines next open1: push cx ;save line counter mov al,179 ;do first character push ax ;save character/attribute stosw mov cx,56 ;do the next 56 characters mov al,32 mov ah,text_attr rep stosw pop ax ;retrieve character/attribute pair stosw ;finish the line add di,44 ;advance DI to next line pop cx ;retrieve line count loop open1 ;loop until all 9 are done mov al,192 ;first character on last line stosw mov cx,56 ;do the next 56 mov al,196 rep stosw mov al,217 ;finish the last line stosw ret open_window endp ; ;------------------------------------------------------------------------------ ;FILL_WINDOW writes a set of key definitions to the open window. ;Entry: DS:SI - key definition table address ;------------------------------------------------------------------------------ fill_window proc near mov bh,video_page ;retrieve video page number lea di,fill_parms ;point DI to parameter table mov cx,7 ;7 lines to write fill1: push cx ;save counter add si,word ptr [di] ;adjust table index mov dx,[di+2] ;set starting cursor position mov cx,[di+4] ;set number of characters call writeln ;write one line add di,6 ;advance parameter table index pop cx ;retrieve count loop fill1 ;loop until done ret fill_window endp ; ;------------------------------------------------------------------------------ ;WRITELN writes one line of key equivalents to the open window. ;Entry: DS:SI - character string address ; BH - video page ; CX - number of characters ; DH,DL - starting row and column ;------------------------------------------------------------------------------ writeln proc near push cx ;save character counter mov ah,2 ;position the cursor int 10h lodsb ;get one character mov ah,10 ;print it mov cx,1 int 10h add dl,3 ;advance cursor position pop cx ;retrieve count loop writeln ;loop until done ret writeln endp ; ;------------------------------------------------------------------------------ ;INITIALIZE prepares the body of the program for residency. ;------------------------------------------------------------------------------ ; SET_DISPLAY_TYPE PROC NEAR ; CHECKS DISPLAY TYPE FOR WINDOWING EACH TIME ; IT IS USED, NOT JUST AT INITIALIZATION. ; MOV AH,15 INT 10H CMP AL,7 JNZ INIT2 MOV ADAPTER,0 MOV VIDEO_SEGMENT,0B000H MOV BORDER_ATTR,70H MOV TEXT_ATTR,07H MOV CURSOR_MODE,0C0DH JMP INIT3 INIT2: MOV ADAPTER,2 MOV VIDEO_SEGMENT,0B800H MOV BORDER_ATTR,2FH MOV TEXT_ATTR,1BH MOV CURSOR_MODE,0607H MOV AX,0C000H MOV ES,AX MOV DI,1EH LEA SI,IBM MOV CX,3 CLD REPE CMPSB JZ INIT3 DEC ADAPTER INIT3: MOV AX,40H MOV ES,AX MOV DI,63H MOV DX,ES:[DI] MOV ADDR_6845,DX MOV CX,CURSOR_MODE MOV AH,1 INT 10H RET ; SET_DISPLAY_TYPE ENDP ; ; ;initialize proc near ; ;See if the display adapter is an EGA. ; ; mov ax,0C000h ;set ES to EGA BIOS segment ; mov es,ax ; mov di,1Eh ;point DI to signature location ; lea si,ibm ;point SI to 'IBM' text ; mov cx,3 ;three bytes to compare ; cld ;clear DF ; repe cmpsb ;check three bytes ; je init1 ;branch if signature found ; ;Determine whether adapter is a CGA or an MDA. ; ; dec adapter ;decrement assumed value ; mov ah,15 ;get current video mode ; int 10h ; cmp al,7 ;is it mode 7? ; jne init1 ;no, then it's a CGA ; ;The display adapter is an MDA. Modify video attributes. ; ; dec adapter ;set ADAPTER value for MDA ; sub video_segment, 800h ;modify video segment value ; mov border_attr,70h ;modify border attribute ; mov text_attr,07h ;modify text attribute ; mov cursor_mode,0C0Dh ;modify default cursor shape ; ;Reset the cursor to its default shape. ; ;init1: mov cx,cursor_mode ;set scan lines in CX ; mov ah,1 ;video function - set cursor ; int 10h ;reset cursor ; ;Get and save the address of the CRT Controller. ; ; mov ax,40h ;point ES to BIOS data area ; mov es,ax ; mov di,63h ;point DI to address word ; mov dx,es:[di] ;get CRTC address ; mov addr_6845,dx ;save it ; INITIALIZE PROC NEAR ; ;Save the old interrupt 9 vector and replace it with a new one. ; mov ax,3509h ;get current interrupt 9 vector int 21h mov old9h_vector,bx ;save it mov old9h_vector[2],es mov ah,25h ;then point it to NEW9H routine lea dx,new9h int 21h ; ;Terminate, leaving additional room for screen buffering. ; mov dx,offset initialize+1276 ;set DX for exit int 27h ;terminate-but-stay-resident initialize endp ; code ends end begin