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Assembly Source File | 1987-07-07 | 16.8 KB | 814 lines

;MEM.ASM code segment assume cs:code,ds:code org 100h start: jmp begin db 5 dup ('stack ') stack_area dw 0 topline db ' CURSOR LOCATION: 00000 CONTENTS: 00',32,32,32 help? db '(? FOR HELP) ' find? db 'FIND:',32,32,32,32,32,32,32,32,32 ;because I'm using Qedit... jump? db 'JUMP TO:',32,32,32,32,32,32 search db 'SEARCHING... ' escmsg db 0,'Press ESC to QUIT',0,0 db 0,'Arrow keys - move cursor',32,32,32,32,32,32,32,32,32,32,32,32 db '(& Ctrl-Left Arrow & Ctrl-Right Arrow)',0 db 0,'Home - left end of line',32,32,32,32,32,32,32,32,32,32,32,32,32 db 'End - right end of line',0 db 0,'Ctrl-Home - top of screen',32,32,32,32,32,32,32,32,32,32,32 db 'Ctrl-End - bottom of screen',0 db 0,'Ctrl-PgUp - beginning of memory',32,32,32,32,32 db 'Ctrl-PgDn - end of memory',0 db 0,'PgUp - previous screen',32,32,32,32,32,32,32,32,32,32,32,32,32,32 db 'PgDn - next screen',0 db 0,'Scroll Lock ON to scroll screen with Arrow Keys',0 db 0,'Ctrl-F - Find string of characters',0 db 0,'Ctrl-L - Continue to search for string',0 db 0,'Ctrl-J - Jump to hexadecimal memory address',0 db 0,0,'PRESS ANY KEY TO RETURN...',0 db 'MEM.COM (c)1987 by Doug Cox ' findstr db 32,32,32,32,32,32,32,32 cursave dw 0 saves dw 0 strcnt dw 0 oldcur dw 0 chars dw 0 curptr dw 0 toplef dw 0 mode db 0 begin: lea ax,stack_area mov sp,ax mov ah,0fh ;function to check screen mode int 10h cmp al,0bh ;indicates display mode jb notega ;if monochrome or CGA jmp exit notega: mov mode,al ;save it mov ax,0b000h ;video memory address cmp mode,7 je mono ;if monochrome display add ax,800h ;if CGA display mono: mov es,ax ;save old cursor location call getcur dec dh mov oldcur,dx ;row in dh / col in dl ;save old screen mov di,0 lea si,oldscr oldlp0: mov cx,80 ;columns oldlp: mov al,es:[di] mov ds:[si],al inc di inc di inc si loop oldlp dec dh ;rows jnz oldlp0 mov ah,0 ;function to set screen mode mov al,2 ;code for 25x80 B&W int 10h ;clear screen mov ah,1 ;function to change cursor shape mov cx,7 ;top & bottom row of cursor int 10h ;put top line on screen lea si,topline mov di,0 ;location on screen mov cx,53 ;for count mov ah,70 ;for screen attribute call movit ;move [si] into [di] & inc di cx times ;put memory contents on screen memtop: mov toplef,0 ;memory location (& data segment) mov curptr,0 ;cursor offset location in memory mov dx,0100h ;row 1/column 0 call movcur ;initialize cursor at top left newscrn:mov ah,7 ;screen attribute mov si,0 ;offset of memory to put on screen mov di,160 ;top left of screen cmp toplef,0ff8ch ;last possible toplef jnc atend ;to not write past 0fffffh mov cx,1920 ;80*24 screen mov ds,toplef ;toplef is also data segment beginning call movit ;lodsb, stosw, loop new2: mov dx,cs mov ds,dx ;put data seg back ;put cursor location & contents at screen top locont: mov dx,toplef ;data segment mov bx,dx ;for first binihex call mov cl,4 shl dx,cl add dx,curptr ;offset addr jnc locont2 add bx,1000h ;increment 5th byte locont2:mov di,36 ;location on screen mov ch,1 ;for count call binihex ;show 5th byte of location mov bx,dx mov ch,4 call binihex ;show other 4 bytes of location mov bx,curptr ;cursor location in memory mov ds,toplef mov bh,[bx] ;contents mov cx,cs mov ds,cx mov di,70 ;screen loc mov ch,2 ;2 chars call binihex ;read keyboard wait: mov ah,0 ;function to read keyboard int 16h ;program stays here, mostly cmp al,0 je extended_code call case ;to jump to following subroutines db ctrls/3 diff2 equ $ db 10 ;^J dw jump db 6 ;^F dw find db 12 ;^L dw again db 3fh ;'?' dw emenu db 1bh ;ESC dw exit ctrls equ $-diff2 dw wait ;if at last possible screen of memory atend: mov dx,toplef mov ds,dx ;don't change ds before getting ds:[toplef] mov cl,4 shl dx,cl ;rotate left 1 byte mov cx,0ffffh sub cx,dx inc cx mov dx,1920 ;80*24 sub dx,cx call movit ;put memory on screen, but put blanks past ffffh mov cx,dx mov ax,0700h ;attribute & blank rep stosw jmp new2 extended_code: mov al,ah call case db extends/3 ;number of routines to check diff1 equ $ db 71 ;Home dw lftside db 79 ;End dw rtside db 73 ;PgUp dw prev db 81 ;PgDn dw next db 72 ;Up arrow dw curup db 80 ;Down arrow dw curdn db 75 ;Left arrow dw curlft db 77 ;Right arrow dw currt db 116 ;Ctrl-Right arrow dw movrt db 115 ;Ctrl-Left arrow dw movlft db 132 ;Ctrl-PgUp dw memtop db 118 ;Ctrl-PgDn dw goend db 119 ;Ctrl-Home dw scrtop db 117 ;Ctrl-End dw scrbot extends equ $-diff1 dw wait ;go there if not one of above ;'?' emenu: call savcur lea si,escmsg call menwrt cmp al,1bh ;ESC je jmpexit cmp al,3 ;^C je jmpexit mov dx,cursave call movcur jmp newscrn jmpexit:jmp exit ;Ctrl-Home scrtop: call getcur ;row in dh & col in dl mov al,80 mul dh sub curptr,ax add curptr,80 ;because top row here is 1 not 0 mov dh,1 ;top row call movcur jmp locont ;Ctrl-End scrbot: call getcur mov al,24 ;bottom row sub al,dh ;cursor row mov ah,80 mul ah add curptr,ax ;now test for end of memory mov ax,toplef mov cl,4 shl ax,cl add ax,curptr jnc scrbot2 ;if not past 0fffffh call curend jmp locont scrbot2:mov dh,24 ;bottom row call movcur jmp locont ;Ctrl-PgDn goend: mov toplef,0ff8ch ;last possible toplef mov curptr,1855 ;80*23+15 mov dx,180fh ;row 24 col 15 call movcur jmp newscrn ;Home lftside:call getcur push dx mov dh,0 sub curptr,dx ;decrement curptr to 1st col pop dx mov dl,0 call movcur jmp locont ;End rtside: mov ax,toplef cmp ax,0ff8ch ;last screen in memory jc rtside2 mov cl,4 shl ax,cl add ax,curptr cmp ax,0fff0h ;beginning of last line in memory jc rtside2 call curend jmp locont rtside2:call getcur mov al,79 sub al,dl mov ah,0 add curptr,ax mov dl,79 call movcur jmp locont ;PgUp prev: cmp toplef,0 je jmpwait cmp toplef,78h ;1920d shifted right (24*80) screen jnc prev2 ;if not within 24*80 of beginning of memory jmp memtop prev2: sub toplef,78h gonew: jmp newscrn ;PgDn next: mov dx,toplef cmp dx,0ff8ch ;last possible toplef jnc jmpwait ;if at end of memory add dx,78h ;1920d shifted right mov toplef,dx mov cl,4 shl dx,cl add dx,curptr jnc gonew ;if cursor won't be past 0fffffh call curend jmp newscrn curjmp: jmp locont ;Left Arrow curlft: call lftcur jnc curjmp jmp newscrn ;Right Arrow currt: call rtcur jnc curjmp jmp newscrn ;Ctrl-Right Arrow movrt: mov cx,10 rtlp: push cx call rtcur pop cx loop rtlp jmp newscrn ;Ctrl-Left Arrow movlft: mov cx,10 lftlp: push cx call lftcur pop cx loop lftlp jmp newscrn jmpwait:jmp wait ;Up Arrow curup: call scrlock jnz up ;if ScrollLock is ON call getcur cmp dh,1 je curup2 ;if on top line dec dh call movcur sub curptr,80 jmp locont curup2: cmp toplef,0 jz jmpwait sub toplef,5 jmp newscrn ;ScrollLock ON up: cmp toplef,0 je jmpwait ;if at beginning of memory sub toplef,5 call getcur cmp dh,24 je downend ;If at bottom inc dh call movcur add curptr,80 ;because of toplef change jmp newscrn jmpwait2:jmp wait ;Down Arrow curdn: call scrlock jnz down ;if ScrollLock is ON cmp toplef,0ff8ch jc curdn3 ;if not at last screen in memory mov ax,toplef mov cl,4 shl ax,cl add ax,curptr add ax,80 jc jmpwait2 ;if move would put cursor past 0fffffh curdn3: call getcur cmp dh,24 je curdn2 ;if on bottom line inc dh call movcur add curptr,80 jmp locont curdn2: add toplef,5 cmp toplef,0ff8ch jc downend ;if not at end of memory call curend jmp newscrn ;don't need to increment curptr ;ScrollLock ON down: cmp toplef,0ff8ch jnc jmpwait2 ;if at end of memory add toplef,5 ;80 shifted right call getcur cmp dh,1 je downend ;if cursor is on top line dec dh call movcur sub curptr,80 ;because of toplef change downend:jmp newscrn ;jump to input hex address jump: call savcur lea si,jump? call top mov bp,96 ;for screen location in getstr call getstr ;get input cmp dx,0 ;input string length jnz jumpsk jmp find15 ;if no input jumpsk: mov si,di ;just after last input char on screen mov ax,0 mov di,ax ;for offset address mov bx,ax ;for segment address mov dx,0004h ;dh for cl & dl for loop ;get offset address jumplp: dec si dec si cmp si,96 ;input screen location jl jumpxit ;if no good input mov al,es:[si] call hex2bin ;convert to binary jc jumplp ;if not hexadecimal mov cl,dh mov ah,0 ;rol changes it add dh,4 ;to rol ax to next nibble to left rol ax,cl or di,ax ;ta daa! dec dl jnz jumplp ;get segment address dec si dec si mov al,es:[si] call hex2bin jc jumpxit mov ah,0 or bx,ax jumpxit:mov saves,es jmp find16 ;to jump to address find: call savcur lea si,find? call top mov bp,90 call getstr ;put string in findstr cmp dx,0 jne find12 jmp find15 ;if no input find12: mov si,90 lea di,findstr mov cx,8 find5: mov al,es:[si] mov ds:[di],al inc si inc si inc di loop find5 ;write 'SEARCHING...' lea si,search mov cx,12 mov di,108 mov ah,7 call movit ;search for string mov di,0 ;beginning of memory offset mov bx,0 mov saves,es mov strcnt,dx ;save it for again: mov cx,0ffffh ;for scasb count ;jumped to from again: find14: mov es,bx ;beginning of memory segment dec dx ;because cmpsb doesn't look at 1st char jnz find10 ;if only one char to find mov al,findstr repnz scasb jmp short find11 ;subroutine to increment segment find9: mov di,0 mov cx,0ffffh add bx,1000h mov es,bx ;to next segment jc find7 ;if past last segment ;big find loop find10: lea si,findstr mov al,[si] repnz scasb ;repeat until z=true or cx=0 jnz find9 ;if string not found in current segment (cx=0) mov bp,di ;save it push cx mov cx,dx ;for cmpsb count inc si ;point to remainder of string repz cmpsb ;compare strings (repeat until z=false or cx=0) pop cx ;get scasb count back mov di,bp ;get it back jnz find10 ;if string not found ;jump to address find11: dec di ;offset addr mov cl,4 rol bx,cl ;move segment addr to right-most byte and bx,0fh ;clear all but right-most byte find16: mov dx,bx ;for div by word mov ax,di mov cx,80 div cx ;remainder is in dx (& dl = column) mov curptr,dx ;column (dh=0) sub di,curptr ;to get toplef jnc find13 dec bx find13: mov cl,4 shr di,cl mov cl,4 ror bx,cl ;back to previous shape add di,bx mov toplef,di ;ta-daa! mov dh,1 ;put cursor on first row mov cursave,dx ;for movcur ;clear message & exit find7: mov es,saves find15: mov ax,700h mov di,108 mov cx,12 rep stosw ;put '? FOR HELP' back lea si,help? call top mov dx,cursave call movcur jmp newscrn ;look for string again again: call savcur lea si,search mov cx,12 mov di,108 mov ah,7 call movit mov dx,strcnt mov saves,es mov di,toplef mov bx,di mov cl,4 rol di,cl and di,0fff0h ;clear right byte add di,curptr ;offset addr inc di ;start looking 1 byte beyond current location jnc againsk add bx,1000h againsk:and bx,0f000h ;clear all but left byte (for seg addr) mov cx,0ffffh sub cx,di ;for count to end of current segment jmp find14 ;return to DOS exit: mov bh,0 ;page 0 mov ah,bh ;function to set screen mode mov al,mode int 10h ;restore old cursor location mov dx,oldcur ;old cursor location dec dh call movcur ;restore old screen inc dh mov di,0 lea si,oldscr exitlp: mov cx,80 ;columns mov ah,7 call movit ;move [si] into [di] & inc di cx times dec dh ;rows jnz exitlp int 20h ;return to DOS ;***CALLED ROUTINES*** top proc near mov cx,14 mov di,78 mov ah,70 call movit ret top endp movit proc near movlp: lodsb stosw loop movlp ret movit endp ;save cursor location savcur proc near call getcur mov cursave,dx mov dx,1900h ;row 25,col 0 jmp short movcur savcur endp ;move cursor to row in dh & col in dl movcur proc near mov ah,2 jmp short cur movcur endp ;put row in dh & col in dl getcur proc near mov ah,3 cur: mov bh,0 int 10h ret getcur endp ;to jump to a subroutine (semi-trick) case proc near pop bx ;RET address mov cl,[bx] ;number of comparisons to make mov ch,0 caslop: inc bx ;to a db cmp al,[bx] je go inc bx ;to a dw inc bx loop caslop go: inc bx ;to a dw mov bx,[bx] jmp bx case endp ;to change binary to hex binihex proc near binlp: mov cl,4 rol bx,cl ;move left byte to right side mov al,bl ;this is necessary and al,0fh ;clear left byte add al,30h cmp al,3ah jl num add al,7 num: stosb inc di dec ch jnz binlp ret binihex endp ;convert al from hex to binary hex2bin proc near cmp al,'0' jl badhex cmp al,'9' jle hex2 ;if number and al,0dfh ;make letters uppercase cmp al,'A' jl badhex cmp al,'F' jg badhex sub al,7 hex2: sub al,30h clc ret badhex: stc ret hex2bin endp ;to put cursor at 0fffffh curend proc near mov dx,toplef mov cl,4 shl dx,cl mov ax,0ffffh sub ax,dx mov curptr,ax mov cl,80 div cl inc al mov dh,al ;quotient (answer) (for row) mov dl,ah ;remainder (for column) jmp short movcur curend endp lftcur proc near call getcur cmp dx,0100h je lfttop ;if at top left of screen dec curptr cmp dl,0 je prevlin dec dl jmp short lftmov prevlin:dec dh mov dl,79 lftmov: call movcur clc lftxit: ret lftcur endp lfttop: cmp toplef,0 je lftxit ;if at beginning of memory mov dl,79 call movcur sub toplef,5 ;80d shifted right add curptr,79 ;because of toplef change stc ret rtcur proc near cmp toplef,0ff8ch jc rtcur2 ;if not at last screen mov ax,toplef mov cl,4 shl ax,cl inc ax add ax,curptr jc rtexit ;if cursor would go beyond 0fffffh rtcur2: inc curptr call getcur cmp dl,79 je nexlin inc dl jmp short rtmov nexlin: cmp dh,24 je rtbot inc dh mov dl,0 rtmov: call movcur clc rtexit: ret rtcur endp rtbot: cmp toplef,0ff8ch ;last toplef in memory jnc rtexit mov dl,0 call movcur add toplef,5 sub curptr,80 ;because of toplef change stc ret scrlock proc near ;check ScrollLock on or off push es mov ax,0 mov es,ax test byte ptr es:[417h],00010000b pop es ret scrlock endp ;get string to search for getstr proc near mov dx,0 ;for count in cmpsb, below mov di,bp find2: mov ah,0 ;read keyboard function int 16h cmp ah,14 ;Backspace key je find20 cmp ah,83 ;Del key je find20 cmp ah,75 ;Left Arrow key je find20 cmp al,8 jne find3 ;if no erase input ;erase char find20: cmp di,bp je find2 ;don't erase if at beginning of input location dec di dec di dec dx mov word ptr es:[di],4620h ;attribute & space jmp short find2 ;put char on screen find3: cmp di,106 ;last input space je find4 ;exit cmp al,0dh ;Enter key je find4 ;exit stosb inc di inc dx jmp short find2 find4: ret getstr endp menwrt proc near mov di,160 mov ax,0 mov cx,5 rep stosw mov ah,7 ;for attribute mov dx,24 ;rows menlp0: mov cx,80 ;columns menlp: lodsb cmp al,0 je mensk stosw loop menlp mensk: rep stosw cmp si,0 jne mensk2 add di,160 mensk2: dec dx jnz menlp0 mov ah,0 int 16h ;read keyboard ret menwrt endp oldscr equ $ code ends end start