page 44,100 TITLE ASMXMPLE
Video equ 10h ;video functions interrupt number Keyboard equ 16h ;keyboard functions interrupt number DOS equ 21h ;call DOS interrupt number PrtSc equ 5h ;Print Screen Bios interrupt CRTstatus equ 03DAh CRTmode equ 03D8h CursOff equ 16134 portb equ 61h ;I/O port B
STACK Segment Para Stack 'Stack' Stak db 64 dup ("stack ") STACK EndS
PARMSEG Segment Para 'data' Asciiz db 63 dup (?) ;Device ID, path and filespec, Xasciiz db '$' ; followed by at least one byte of
; of binary zero.
Handle dw ? ;Place to put 16 bit handle number Bufseg dw ? ;Segment address of buffer Bufoff dw ? ;Offset of buffer Bufsiz dw ? ;Max bytes to read/write Actsiz dw ? ;Actual bytes read Dskerr dw ? ;DOS error code, if error occurs Parmseg EndS
DATASEG Segment Para 'data' IObuffer db 4096 dup (?) ;I/O buffer for reading screens
; from disk.
Pgmstat db 0 ;program status switch Cover db 'ICOVER.SCN'
db 0
FileSpec db 'INSTRC**.SCN'
db 0
PageNbr db 0 NewPage db ' ' Ten db 10 EdgeTab db 7,7,3,0,0,0,0,0
db 0,0,0,0,7,7,4,0
db 6,6,3,0,3,6,6,6
db 7,0,2,5,5,5,3,6
db 6,6,6,3,6,6,6,6
db 3,3,11,15,10,0,0,0
StartOff dw 0 Keycodes dw 0 Answer db 256 dup (?) MaxChars dw 0 Attributes dw 0 Buzzit db 0 Dataseg EndS
ScreenSeg Segment at 0B800h ;location of color screen mem Page0 db 4096 dup (?) Page1 db 4096 dup (?) Page2 db 4096 dup (?) Page3 db 4096 dup (?) ScreenSeg EndS
CODE Segment Para 'code' assume cs:CODE
MAIN Proc Far
push ds mov ax,0 push ax assume ds:dataseg mov ax,dataseg mov ds,ax mov dl,0 ;set starting page number to zero mov PageNbr,dl call ShowCover ;Put instructions cover on screen cmp Pgmstat,0 jne InstructX ;some was wrong PageMore: call PutScreen ;Get instruction screen from disk
; and display it.
call NextNumber ;get next page number, etc. cmp PageNbr,255 jne PageMore InstructX: mov ah,11 ;set color palette mov bh,0 ;set boarder color mov bl,0 ;black int video ;call bios video routine mov ah,0 ;set mode function mov al,3 ;80 x 25 color int video ;bios call to video rom routines mov ah,5 ;select active display page mov al,0 ;page 0 int video ;bios call mov ah,1 mov ch,7 mov cl,7 ret ;return to dos MAIN EndP
ShowCover Proc Near push ds push es call Cover1 assume ds:dataseg cmp PageNbr,0 jne CoverX AnyKey: mov ah,0 ;read next key struck from keyboard int keyboard ;call bios keyboard routine CoverX: pop es pop ds ret ShowCover EndP
Cover1 Proc Near push ds push es assume ds:dataseg assume es:parmseg mov ax,parmseg mov es,ax cmp PageNbr,0 jne CoverOk ;Set disk parms, start by moving file spec to Asciiz. mov si,offset cover mov di,offset asciiz mov cx,64 cld rep movsb mov es:bufseg,ds ;set segment address of buffer mov ax,offset IObuffer ;set offset of buffer mov es:bufoff,ax mov ax,4008 ;set size of screen block mov es:bufsiz,ax call GetFile ;get screen from disk cmp es:DskErr,0 je CoverOK ;read was OK mov al,1 mov pgmstat,al jmp CoverX Coverok: mov al,3 ;80 x 25 color mov ah,0 ;set mode int video ;call bios video routine mov ah,5 ;select active display page mov al,3 ;active page 3 int video ;call bios video routine mov ah,11 ;set color palette mov bh,0 ;set boarder color mov bl,1 ;dark blue int video ;call bios video routine mov ah,1 ;make cursor invisible mov ch,31 mov cl,31 int video cmp PageNbr,0 jne Cover1X mov dx,CRTmode ;turn off the display mov al,29h ;mode byte for 80 column color and al,11110111b out dx,al assume es:screenseg mov ax,screenseg mov es,ax mov si,offset IObuffer+7 ;Move screen from I/O buffer to mov di,offset Page3 ; to actual screen memory. cld mov cx,2000 rep movsw mov dx,CRTmode ;turn display back on mov al,29h ;80 x 25 color mode byte out dx,al call beep Cover1X: pop es pop ds ret Cover1 EndP
PutScreen Proc Near push ds push es ReStart: assume ds:dataseg mov al,PageNbr ;get instruction screen page number call ConvByte ;convert to decimal display mov FileSpec+6,dh ;and put it into the file spec mov FileSpec+7,dl assume es:parmseg mov ax,parmseg mov es,ax ;Set disk parms, start by moving file spec to Asciiz. mov si,offset FileSpec mov di,offset asciiz mov cx,64 cld rep movsb mov es:bufseg,ds ;set segment address of buffer mov ax,offset IObuffer ;set offset of buffer mov es:bufoff,ax mov ax,4008 ;set size of screen block mov es:bufsiz,ax call GetFile ;get screen from disk cmp es:DskErr,0 je ScreenOK ;read was OK jmp NoPage ;not a valid screen page number ScreenOK: call SetEdge mov dx,CRTmode ;turn off the display mov al,29h ;mode byte for 80 column color and al,11110111b out dx,al assume es:screenseg mov ax,screenseg mov es,ax mov si,offset IObuffer+7 ;Move screen from I/O buffer to mov di,offset Page3 ; to actual screen memory. cld mov cx,2000 rep movsw mov dx,CRTmode ;turn display back on mov al,29h ;80 x 25 color mode byte out dx,al call beep jmp PSexit NoPage: call buzz call ClearAns mov al,0 mov PageNbr,al jmp ReStart PSexit: pop es pop ds ret PutScreen EndP
NextNumber Proc Near push ds push es WaitInput: mov si,CursOff ;offset to cursor position on screen mov cx,2 ;max characters in answer mov dh,0BCh ;cursor color atribute mov dl,031h ;answer color atribute call Xanswer assume es:dataseg mov ax,dataseg mov es,ax cmp dh,1 je PrevPage ;go to previous page cmp dh,2 je NextPage ;go to next page cmp cx,0 je PageZero ;go to page 0 cmp cx,01FFh je MainMenu ;escape back to main menu push cx mov di,offset NewPage ;move answer to local work area cld mov cx,2 rep movsb pop cx cmp cx,1 jne TwoDigit OneDigit: call ConvOne cmp ah,0 jne BadNumber mov es:PageNbr,al jmp NNexit TwoDigit: call ConvTwo cmp ah,0 jne BadNumber mov es:PageNbr,al jmp NNexit PrevPage: cmp es:PageNbr,0 je BadNumber dec es:PageNbr jmp NNexit Nextpage: inc es:PageNbr jmp NNexit PageZero: mov al,0 mov es:PageNbr,al jmp NNexit MainMenu: mov al,255 mov es:PageNbr,al jmp NNexit BadNumber: call buzz call ClearAns jmp WaitInput NNexit: pop es pop ds ret NextNumber EndP
ConvOne Proc Near push ds push es assume ds:dataseg mov ax,dataseg mov ds,ax mov al,NewPage cmp al,30h jl NotNumber1 cmp al,39h jg NotNumber1 sub al,30h ;convert to binary mov ah,0 jmp COexit NotNumber1: mov ah,1 COexit: pop es pop ds ret ConvOne EndP
ConvTwo Proc Near push ds push es assume ds:dataseg mov ax,dataseg mov ds,ax mov al,NewPage cmp al,30h jl NotNumber2 cmp al,39h jg NotNumber2 sub al,30h ;convert to binary mul Ten ;multiply by 10 mov dl,al ;save in dl mov al,NewPage+1 cmp al,30h jl NotNumber2 cmp al,39h jg NotNumber2 sub al,30h ;convert to binary add al,dl ;add 10's value mov ah,0 jmp CTexit NotNumber2: mov ah,1 CTexit: pop es pop ds ret ConvTwo EndP
ClearAns Proc Near push ds push es assume ds:screenseg mov ax,screenseg mov ds,ax mov al,20h mov bx,CursOff mov [page0 + bx],al inc bx mov [page0 + bx],al inc bx mov [page0 + bx],al pop es pop ds ret ClearAns EndP
SetEdge Proc Near push ds push es assume ds:dataseg mov ax,dataseg mov ds,ax mov bl,PageNbr mov bh,0 mov ch,[EdgeTab + bx] mov ah,11 mov bh,0 mov bl,ch int video pop es pop ds ret SetEdge EndP
;Subroutine to get a binary block of data from disk. ;It opens file, reads entire file (as one block of data) ;into memory, closes file. ; ;Enter with: ; - Device, path, filespec and binary zero in Asciiz. ; - Segment address of buffer in Bufseg. ; - Offset of buffer in Bufoff. ; - Max number of bytes to read, in Bufsiz. ; ;On exit: ; - Handle will contain handle number. ; - Actsiz will contain actual number of bytes read, or ; zero if file was not found on disk. ; - Dskerr will contain the DOS error code, or zero if ; no error.
Getfile Proc Near push ds ;save registers of calling routine push es push si push di push ax push bx push cx push dx assume ds:parmseg mov ax,parmseg ;set DS to PARMSEG segment mov ds,ax ; -which sets DS to Asciiz mov dx,offset asciiz ; -set offset to Asciiz mov al,0 ;set AL to "open for reading" mov ah,3dh ;set AH to "open a file" function int DOS ;call DOS jc gfopenerr ;error on open mov handle,ax ;save handle mov bx,handle ;load BX with file handle mov cx,bufsiz ;load CX with # of bytes to read mov dx,bufoff ;load DX with offset of buffer mov ax,bufseg ;load DS with segment address mov ds,ax ; of buffer mov ah,3fh ;"read from a file" function int DOS ;call DOS push ax ;save # of bytes read on stack mov ax,parmseg ;restore DS to diskparms segment mov ds,ax ; pop ax ;get # of bytes read jc gfreaderr ;error on read mov actsiz,ax ;save # of bytes read, in diskparms mov bx,handle ;load BX with file handle mov ah,3eh ;"close a file handle" function int DOS ;call DOS jc gfcloserr ;error on close mov dskerr,0 ;set error code to zero (no error) Gfback: pop dx ;restore registers of calling pop cx ; routine. pop bx pop ax pop di pop si pop es pop ds ret ;return to calling routine ;ERROR ON OPEN: Possible error returns are: ; 2 - File not found ; 4 - To many open files (no handles left) ; 5 - Access denied ; 12 - Invalid access code Gfopenerr: mov ah,1 ;set AH to 1 for open error,
;AL already contains error code
mov dskerr,ax ;put error code in diskparms jmp gfback ;ERROR ON READ: Possible error returns are: ; 5 - Access denied ; 6 - Invalid handle Gfreaderr: mov ah,2 ;set AH to 2 for read error mov dskerr,ax ;put error code in diskparms jmp gfback ;ERROR ON CLOSE: Possible error return is: ; 6 - Invalid handle Gfcloserr: mov ah,3 ;set AH to 3 for close error mov dskerr,ax ;put error code in diskparms jmp gfback Getfile EndP
Beep Proc Near push ax ;save registers of calling program push dx push cx push bx mov ax,0 mov dx,12h mov cx,7d0h div cx mov bx,ax mov al,10110110b out 43h,al mov ax,bx out 42h,al mov al,ah out 42h,al in al,portb or al,3 out portb,al mov cx,07fffh ;set up counter for duration of beep wait: loop wait in al,portb and al,11111100b out portb,al pop bx ;restore registers of calling pgm pop cx pop dx pop ax ret BEEP EndP
BUZZ Proc Near push ax ;save registers of calling program mov ax,ds push ax push bx push cx push dx assume ds:dataseg mov ax,dataseg ;set DS for this routine mov ds,ax mov buzzit,16 ;set buzz counter Buzzone: mov ax,0 mov dx,12h mov cx,900 div cx mov bx,ax mov al,10110110b out 43h,al mov ax,bx out 42h,al mov al,ah out 42h,al in al,portb or al,3 out portb,al mov cx,0affh Buzz1: loop buzz1 in al,portb and al,11111100b out portb,al mov cx,7ffh Buzz2: loop buzz2 dec buzzit jnz buzzone pop dx pop cx pop bx pop ax mov ds,ax pop ax ret BUZZ EndP
;Enter with binary value in AL. ;On return, the result is in: (assume result is 234) ; AH = 2, DH = 3, DL = 4 Convbyte Proc Near push ds push es mov ah,48 mov dh,48 mov dl,48 Test1: cmp al,100 jl test2 sub al,100 inc ah jmp test1 Test2: cmp al,10 jl test3 sub al,10 inc dh jmp test2 Test3: add dl,al pop es pop ds ret Convbyte EndP
;Enter with: ; SI = offset of cursor position in screen memory ; CX = maximum number of characters in answer ; DH = color atribute of cursor ; DL = color atribute of answer ;On return: ; The answer is on the screen, followed by the cursor. ; The answer is also in a string pointed to by DS SI, ; with CX set to the number of characters in the answer. ; If Escape was pushed CX will = 01FFh. ; DH will = 0, unless PgUp pushed then DH = 1 ; or PgDn pushed then DH = 2. Xanswer Proc Near push ds push es assume ds:screenseg mov ax,screenseg mov ds,ax assume es:dataseg mov ax,dataseg mov es,ax mov es:Attributes,dx ;save color attributes mov es:StartOff,si ;save beginning offset mov es:MaxChars,cx ;save maximum number of characters
; in answer.
mov cx,256 mov bx,0 mov al,20h ClearAnswer: mov [es:answer + bx],al inc bx loop ClearAnswer mov cx,0 ;initialize character counter NextChar: call PutCursor ;Put cursor on screen mov ah,0 int keyboard ;read next keyboard entry mov es:keycodes,ax ;save codes cmp al,20h jl ChekEdit ;not a printable character cmp al,7Eh jg ChekEdit ;not a printable character cmp cx,es:MaxChars jge BadChar ;already have max number of char's call PutChar ;put character on screen inc si ;bump offset to screen by 1 char' inc si ; which is 2 bytes. mov bx,cx ;move counter to pointer mov ax,es:keycodes ;get character code mov [es:Answer + bx],al ;and put in answer string inc cx ;bump character counter jmp NextChar ChekEdit: cmp ax,0E08h ;backspace je BackUp cmp ax,4B00h ;left arrow je BackUp cmp ax,1C0Dh ;return je Return cmp ax,011Bh ;escape je Escape cmp ah,49h ;PgUp je PageUp cmp ah,51h ;PgDn je PageDown BadChar: call buzz ;invalid character or control jmp NextChar BackUp: cmp cx,0 jle BadChar ;can't back up mov es:keycodes,02020h ;set keycodes to space call PutChar ;blank out cursor on screen dec cx ;decrement character counter dec si ;decrement offset pointer dec si ; (2 bytes per character) jmp NextChar ;and start over Escape: mov cx,01FFh mov dh,0 jmp Return2 PageUp: mov dh,1 jmp Return2 PageDown: mov dh,2 jmp Return2 Return: mov dh,0 Return2: mov es:keycodes,02020h ;set keycodes to space call PutChar ;blank out cursor on screen assume ds:dataseg mov ax,dataseg mov ds,ax mov si,offset answer pop es pop ds ret Xanswer EndP
PutCursor Proc Near assume ds:screenseg assume es:dataseg mov bx,es:attributes mov bl,219 mov dx,CRTstatus Wait1: in al,dx test al,1 jnz Wait1 Wait2: in al,dx test al,1 jz Wait2 cli mov [Page0 + si],bl mov [Page0 + 1 + si],bh sti ret PutCursor EndP
PutChar Proc Near push dx assume ds:screenseg assume es:dataseg mov bx,es:attributes mov bh,bl mov ax,es:keycodes mov bl,al mov dx,CRTstatus WaitA: in al,dx test al,1 jnz WaitA WaitB: in al,dx test al,1 jz WaitB cli mov [Page0 + si],bl mov [Page0 + 1 + si],bh sti pop dx ret PutChar EndP
CODE EndS END