Microsoft Programmer's Library 1.3

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Assembly Source File | 1988-08-11 | 11.2 KB | 305 lines

TITLE Pager .MODEL small, pascal INCL_VIO EQU 1 INCLUDE os2.inc .DATA EXTRN stAtrib:BYTE, scAtrib:BYTE, Cell:WORD, stLine:BYTE EXTRN sBuffer:WORD, oBuffer:WORD, Buffer:DWORD, lBuffer:WORD EXTRN nLines:WORD, curLine:WORD .CODE PUBLIC Pager ; Procedure Pager ; Purpose Displays status and text lines ; Input Stack variable: lines to scroll (negative up, positive down) ; Global variables: "sbuffer", "oBuffer", "curLine" ; Output To screen Pager PROC count mov es, sBuffer ; Initialize buffer position mov di, oBuffer mov cx, count ; Get count argument mov ax, 10 ; Search for linefeed or cx, cx ; Argument 0? jl skip1 ; If below, backward jg skip2 ; If above, forward jmp SHORT skip3 ; If equal, done skip1: call GoBack ; Adjust backward jmp SHORT skip3 ; Show screen skip2: call GoForwd ; Adjust forward ; Write line number to status line skip3: cld ; Go forward push di ; Save push ds ; ES = DS pop es ; BinToStr (curLine, OFFSET stLine[6]) push curLine ; Arg 1 @Pushc <OFFSET stLine[6]> ; Arg 2 call BinToStr ; Convert to string ; Fill in status line mov cx, 6 ; Six spaces to fill sub cx, ax ; Subtract those already done mov al, " " ; Fill with space rep stosb @VioWrtCharStrAtt stLine, 80, 0, 0, stAtrib, 0 ; Write to screen pop di ; Update position mov si, di mov cx, nLines ; Lines per screen loop1: mov bx, nLines ; Lines of text inc bx ; Adjust for 0 sub bx, cx ; Calculate current row push cx ; Save line number ; ShowLine (position, line, maxlength, &scAtrib) push sBuffer ; Arg 1 push si push bx ; Arg 2 push lBuffer ; Arg 3 push ds ; Arg r4 @Pushc <OFFSET scAtrib> call ShowLine ; Write line pop cx ; Restore line number mov si, ax ; Get returned position cmp ax, lBuffer ; If beyond end of file, jae skip4 ; fill screen with spaces loop loop1 ; else next line jmp SHORT exit ; Exit if done ; Fill the rest with spaces skip4: dec cx jcxz exit mov ax, 80 ; Columns times remaining lines mul cl mov dx, ax ; Macros use AX, so use DX sub cx, nLines ; Calculate starting line neg cx inc cx @VioWrtNCell Cell, dx, cx, 0, 0 ; Write space cells exit: ret Pager ENDP ; Procedure ShowLine (inLine, sRow, &pAtrib) ; Purpose Writes a line to screen ; Input Stack variables: 1 - FAR PTR to input line ; 2 - line number ; 3 - maximum number of characters (file length) ; 4 - FAR PTR to attribute ; Output Line to screen ShowLine PROC USES si di, inLine:FAR PTR BYTE, srow, max, pAtrib:FAR PTR BYTE LOCAL outLine[80]:BYTE push ds ; Save push ss ; ES = SS pop es lea di, outLine ; Destination line lds si, inLine ; Source line mov cx, 80 ; Cells per row mov bx, di ; Save copy of start for tab calc loop1: lodsb ; Get character cmp al, 9 ; Tab? je skip1 ; Space out tab cmp al, 13 ; CR? je skip3 ; Fill rest of line with spaces stosb ; Copy out cmp si, max ; Check for end of file ja skip3 loop loop1 loop2: lodsb ; Throw away rest of line to truncate cmp si, max ; Check for end of file ja exit cmp al, 13 ; Check for end of line jne loop2 inc si ; Throw away line feed jmp SHORT exit ; Done skip1: push bx ; Fill tab with spaces push cx sub bx, di ; Get current position in line neg bx mov cx, 8 ; Default count 8 and bx, 7 ; Get modulus sub cx, bx ; Subtract mov bx, cx ; Save modulus mov al, " " ; Write spaces rep stosb pop cx sub cx, bx ; Adjust count jns skip2 ; Make negative count 0 sub cx, cx skip2: pop bx jcxz loop2 ; If beyond limit done jmp SHORT loop1 skip3: inc si ; After CR, throw away LF mov al, ' ' ; Fill rest of line rep stosb exit: pop ds @VioWrtCharStrAtt outLine, 80, [srow], 0, [pAtrib], 0 mov ax, si ; Return position ret ShowLine ENDP ; Procedure GoBack ; Purpose Searches backward through buffer ; Input CX has number of lines; ES:DI has buffer position ; Output Updates "curLine" and "oBuffer" GoBack PROC std ; Go backward neg cx ; Make count positive mov dx, cx ; Save a copy inc cx ; One extra to go up one or di, di ; Start of file? je exit ; If so, ignore loop1: push cx ; else save count mov cx, 0FFh ; Load maximum character count cmp cx, di ; Near start of buffer? jl skip1 ; No? Continue mov cx, di ; else search only to start skip1: repne scasb ; Find last previous LF jcxz skip4 ; If not found, must be at start pop cx loop loop1 cmp curLine, -1 ; End of file flag? jne skip2 ; No? Continue add di, 2 ; Adjust for cr/lf mov oBuffer, di ; Save position call EndCount ; Count back to get line number ret skip2: sub curLine, dx ; Calculate line number jg skip3 mov curLine, 1 ; Set to 1 if negative skip3: add di, 2 ; Adjust for cr/lf mov oBuffer, di ; Save position ret skip4: pop cx sub di, di ; Load start of file mov curLine, 1 ; Line 1 mov oBuffer, di ; Save position exit: ret GoBack ENDP ; Procedure GoForwd ; Purpose Searches forward through a buffer ; Input CX has number of lines; ES:DI has buffer position ; Output Updates "curLine" and "oBuffer" GoForwd PROC cld ; Go forward mov dx, cx ; Copy count loop1: push cx ; Save count mov cx, 0FFh ; Load maximum character count mov bx, lBuffer ; Get end of file sub bx, di ; Characters to end of file cmp cx, bx ; Less than maximum per line? jb skip1 mov cx, bx skip1: repne scasb ; Find next LF jcxz exit ; If not found, must be at end cmp di, lBuffer ; Beyond end? jae exit pop cx loop loop1 add curLine, dx ; Calulate line number mov oBuffer, di ; Save position ret exit: pop cx mov di, oBuffer ; Restore position ret GoForwd ENDP ; Procedure EndCount ; Purpose Counts backward to count lines in file ; Input ES:DI has buffer position ; Output Modifies "curLine" EndCount PROC push di mov al, 13 ; Search for CR mov curLine, 0 ; Initialize loop1: inc curLine ; Adjust count mov cx, 0FFh ; Load maximum character count cmp cx, di ; Near start of buffer? jl skip1 ; No? Continue mov cx, di ; else search only to start skip1: repne scasb ; Find last previous cr jcxz exit ; If not found, must be at start jmp SHORT loop1 exit: pop di ret EndCount ENDP ; Procedure BinToStr (number, string) ; Purpose Converts integer to string ; Input Stack arguments: 1 - Number to convert; 2 - Near address for write ; Output AX has characters written BinToStr PROC number, string:PTR BYTE mov ax,number mov di,string sub cx, cx ; Clear counter mov bx, 10 ; Divide by 10 ; Convert and save on stack backwards loop1: sub dx, dx ; Clear top div bx ; Divide to get last digit as remainder add dl, "0" ; Convert to ASCII push dx ; Save on stack or ax, ax ; Quotient 0? loopnz loop1 ; No? Get another ; Take off the stack and store forward neg cx ; Negate and save count mov dx, cx loop2: pop ax ; Get character stosb ; Store it loop loop2 mov ax, dx ; Return digit count ret BinToStr ENDP END