Gold Medal Software 2

home *** CD-ROM | disk | FTP | other *** search

/ Gold Medal Software 2 / Gold Medal Software Volume 2 (Gold Medal) (1994).iso / prog / asm_0_m.arj / ALIAS1.ASM < prev next >

Wrap

Assembly Source File | 1990-01-04 | 82KB | 2,621 lines

page 66,132 ;============================================================================ ; ALIAS.COM adds a command line stack, a command line editor, and ; an alias function to COMMAND.COM. Syntax is: ; ; ALIAS [alias [command]] [/F filename] [/S nn] [/U] ; [/B] [/E] [/D] [/L] [/U] [/*] [//] ; ; where /B = Set size of buffer for future alias commands ; /D = Disable alias translation ; /E = Enable alias translation ; /F = Filename of file with list of commands ; /L = List aliases currently in list ; /M = Set minimum command length to save ; /S = Size of command line stack where "nn" is the number of commands ; to save ; /U = Uninstall the program ; /* or // = Comment. Ignore remainder of the line. ; ; ; Revision History: ; ; Version 1.0 Initial Release PC Magazine Vol 8 Num 22 ; ; Version 1.1 Fixed %% bug January 3, 1989 ; Fixed DOS 3.2 bug ; Now works in OS/2 DOS box ; Support for COMMAND.COM shelling ; Reduced installation memory requirments ; ;============================================================================ code segment assume cs:code org 2ch env_segment dw ? ;Word containing the segment ; of the program's env. block. org 80h command_tail db ? ;Offset of the command tail. org 100h main: jmp initialize program db 13,10,"ALIAS 1.1 " copyright db "(c) 1990 Ziff Communications Co.",10,13 authors db "PC Magazine ",254," Doug Boling and Jeff Prosise" db 10,13,"$",1Ah ; ;Change the following two numbers to adjust the size of alias on installation. ; filebuf_size dw 0400h ;Size of input file buffer. max_code_size dw 0AF0h ;Max size of installed code. aliaslist_ptr dd ? ;Pointer to alias list. aliaslist_size dw ? ;Pointer to end of list seg work_buff_ptr dw ? ;Pointer to alias working buff chk_alias db 1 ;Alias enable flag. minlength db 1 ;Minimum len of cmd to stack cmdstack_base dw ? ;Offset of command stack cmdstack_size dw 16 ;Size of command stack. cmdcom_psp dw 0 ;Segment of COMMAND.COM PSP master_env dw 0 ;Segment of master environment cef_pointer dd ? ;Pointer to critical err flag dos_version dw 0 ;DOS Version number mystack_ptr dw offset end_of_resident + 512 ;Ptr to internal stack saved_ss dw ? saved_sp dw ? int21h dd -1 ;Int 21 vector (DOS) int2fh dd -1 ;Int 2f vector (DOS MULTIPLEX) multiplex_id db 0dbh ;Program ID for multiplex int points dw ? ;Scan lines per character columns db ? ;Number of screen columns cursor_mode dw ? ;Cursor mode bufferptr db ? ;Input buffer pointer next_ptr dw 0 ;Address where next command ; will be stored cmd_ptr dw 0 ;Address of current command ; in command stack insert_flag db 0 ;0 = insert off, 1 = on exkeys db 71,72,75,77,79,80 ;Extended keycode list db 82,83,115,116,117 exkeys_end = $ ex_entry dw offset ctrl_end ;Jump table for extended dw offset ctrl_right ; keycodes dw offset ctrl_left dw offset delete dw offset toggle_ins dw offset next_cmd dw offset eol dw offset move_right dw offset move_left dw offset prev_cmd dw offset home ;============================================================================ ; DOSINT processes calls to interrupt 21h ;============================================================================ dosint proc far assume cs:code,ds:nothing,es:nothing cmp ah,0ah ;Check for char input je dosint_1 ;If so, continue goto_dos: jmp cs:[int21h] ;else pass the call to DOS ; ;Compare the active PSP with COMMAND.COM PSP. ; dosint_1: push ax ;Save registers push bx mov ah,51h ;Get active PSP segment cmp word ptr cs:[dos_version],310h jb early_dos pushf call cs:[int21h] jmp short chkpsp1 early_dos: push es ;If before DOS 3.1, set les bx,cs:[cef_pointer] ; critical error flag to inc byte ptr es:[bx] ; force DOS to use the aux pushf ; stack. call cs:[int21h] ;Get active PSP segment mov ax,bx les bx,cs:[cef_pointer] ;Reset critical error flag dec byte ptr es:[bx] mov bx,ax pop es chkpsp1: cmp bx,cs:[cmdcom_psp] ;See if COMMAND.COM active. je dosint_2 push es ;If the active PSP has an mov es,bx ; environment block at a mov ax,es:[2ch] ; higher memory address than dec ax ; the PSP, assume that the mov es,ax ; the active program is a cmp byte ptr es:[0],"M" ; shelled copy of COMMAND.COM pop es jne chkpsp2 ;Valid memory block? cmp ax,bx ;Env seg > PSP seg? jae dosint_2 ;Yes, must be shelled copy chkpsp2: pop bx ;Cleanup and goto DOS pop ax jmp short goto_dos dosint_2: cld ;Set direction flag mov cs:[saved_ss],ss ;Save SS:SP mov cs:[saved_sp],sp cli push cs ;Move to internal stack pop ss mov sp,cs:[mystack_ptr] sti push bp ;Save remaining registers. mov bp,sp ;Set up stack access push cx push dx push di push si push ds push es ; ;The call is from COMMAND.COM. Invoke line editor. ; push dx call cmd_input pop dx cmp cs:[cmdstack_size],0 je dosint_3 call cmd_record ; ;Check for alias before returning to COMMAND.COM ; dosint_3: cmp cs:[chk_alias],0 ;See if alias translation je dosint_exit ; is enabled. mov si,[bp-4] ;Get pointer to input buffer inc si xor cx,cx or cl,ds:[si] ;Get length of buffer je dosint_exit ;If buffer empty, exit. inc si ;Point to 1st char in buffer mov ax,cs mov es,ax ;Set ES to installed code. call searchalias ;See if an alias is found. jc dosint_exit ;No, exit. ; ;If alias found, copy it from alias list to internal buffer. ; mov si,di ;Load SI with alias pointer mov ax,es mov ds,ax ;Point DS to alias list seg xor cx,cx mov cl,ds:[si+3] ;Get size of alias call getalias ;Get alias from list ; ;Append remainder of command line to alias if no cmd line parameters were used. ; or dx,dx ;See if any command line jne dosint_6 ; parameters were used. push si ;Save pointer to buffer. push ds mov di,si add di,cx ;Point DI to end of alias mov dx,cx ;Save length of alias mov si,[bp-4] ;Point DS:SI to command.com mov ds,[bp-10] ; data buffer. xor cx,cx inc si mov cl,[si] ;Get length of command line. cmp ah,cl ;See if enough space in ja dosint_4 ; internal buffer. If not mov cl,ah ; copy only until buff full. dosint_4: inc si mov bl,1 ;Skip past alias. call scan4char jc dosint_5 dec si ;Back up 1 char inc cx add dx,cx ;Add length of command line. rep movsb ;Copy command line dosint_5: mov cx,dx ;Restore length of command pop ds ;Restore pointer pop si ; ;Copy alias from internal buffer to COMMAND.COM data buffer. ; dosint_6: mov di,[bp-4] ;Point ES:DI to command.com mov es,[bp-10] ; data buffer. mov al,es:[di] ;Get size of data buffer dec al ;If alias longer than buffer, cmp al,cl ; copy only the enough ja dosint_7 ; characters to fill the xor cx,cx ; buffer. mov cl,al dosint_7: inc di ;Move DI past length bytes mov es:[di],cl ;Save length of command inc di rep movsb ;Copy alias. mov byte ptr es:[di],13 ;Append carriage return dosint_exit: mov cx,cs:[cursor_mode] ;Set default cursor mov ah,1 int 10h pop es pop ds pop si pop di pop dx pop cx pop bp cli mov ss,cs:[saved_ss] ;Restore stack pointer mov sp,cs:[saved_sp] pop bx pop ax iret ;Return to COMMAND.COM dosint endp ;----------------------------------------------------------------------------- ; GETALIAS Copies an alias from the alias list while substituting any ; environment variables and command line parameters. ; Entry: DS:SI - pointer to alias ; Exit: DS:SI - pointer to buffer containing translated alias. ; AH - free space in buffer ; CX - length of the alias ;----------------------------------------------------------------------------- getalias proc near mov di,work_buff_ptr ;Point DI to internal buffer xor ax,ax ;Point to command by adding mov al,ds:[si+2] ; the size of the alias to add si,ax ; pointer to the entry. add si,4 ;Move past list data. mov ah,126 ;AH contains max size of buff xor dx,dx ;Clear flag for line params alias_1: lodsb ;Get byte from alias cmp al,"%" ;See if special character je alias_3 ;Yes, process special char. alias_2: stosb ;Store byte from alias dec ah ;Dec buffer size counter jz alias_6 ;If internal buffer full, done loop alias_1 jmp short alias_6 ;If at end of alias, done ; ;A percent sign has been found indicating a 'soft' parameter. ; alias_3: ; mov al,ds:[si] ;Get character after % lodsb dec cx cmp al,"%" ;If double %, include in one je alias_2 ; % in alias. mov bh,al ;Copy and check to see if sub bh,"0" ; the next char is a number. jb alias_5 ; If so, assume a line cmp bh,9 ; parameter. ja alias_5 call sublineparam ;Substitute a line paramter inc dx alias_4: loop alias_1 jmp short alias_6 ;If at end of alias, done alias_5: dec si ;Backup to 1st character inc cx call subenvvar ;Substitute an environment var loop alias_1 alias_6: mov si,work_buff_ptr ;Point SI to internal buffer mov cx,di ;Compute size of completed sub cx,si ; alias. ret getalias endp ;----------------------------------------------------------------------------- ; SUBLINEPARAM substitutes a parameter from the command line into the alias. ; Entry: DS:SI - pointer to alias ; ES:DI - pointer to buffer to copy the line parameter ; AH - remaining space in the internal buffer ; BH - binary number of the line parameter ; CX - length of the alias ; Exit: ES:DI - pointer to byte after the parameter in the buffer ; DS:SI - pointer to the character after the line parameter number ; CX - remaining length of the alias ;----------------------------------------------------------------------------- sublineparam proc near push cx push si push ds mov si,[bp-4] ;Get pointer to command.com mov ds,[bp-10] ; data buffer. xor cx,cx mov cl,ds:[si+1] ;Get number of chars in buffer. inc si ;Point to the first byte of inc si ; data. sublineparam_1: or bh,bh ;Check count of param to find. jz sublineparam_2 mov bl,1 call scan4char ;Find next space jc sublineparam_exit dec bl call scan4char ;Find next word jc sublineparam_exit dec bh ;Dec parameter count jne sublineparam_1 ;If not done, loop back. dec si ;Backup to 1st char in word. sublineparam_2: lodsb ;Get character from parameter cmp al," " ;If space, parameter done jbe sublineparam_exit stosb dec ah ;Dec buffer size counter jnz sublineparam_2 sublineparam_exit: pop ds pop si pop cx ret sublineparam endp ;----------------------------------------------------------------------------- ; SUBENVVAR substitutes an environment variable into alias. ; Entry: DS:SI - pointer to variable to substitute ; ES:DI - pointer to buffer to copy the contents of the variable ; AH - remaining space in internal buffer ; CX - length of alias string ; Exit: DS:SI - pointer to the byte after the variable name ; ES:DI - pointer to the byte after the variable contents ; CF - set if variable not found ;----------------------------------------------------------------------------- subenvvar proc near push dx push ds push es ; ;Compute the length of the variable name. ; mov bx,di ;Save pointer to internal buff mov di,si ;Compute the length of the mov dx,cx ; environment variable by mov al,"%" ; searching for the trailing repne scasb ; % sign. sub dx,cx ;Compute length of variable. dec dx ;Subtract % byte fron length. push di ;Save ptr to end of env var. ; ;Search the Master Environment block for the variable pointed to by DS:SI ; mov es,cs:[master_env] ;Get segment of master env blk xor di,di ;Point ES:DI to environment. push cx ;Save alias size. push bx ;Save ptr to internal buffer mov bx,si ;Save pointer to var name subenvvar_1: mov si,bx ;Get back ptr to var name. mov cx,dx ;Compare env var to var in repe cmpsb ; alias. je subenvvar_2 ;Variable found, exit loop xor al,al ;Find next environment var. mov cx,-1 ;Scan the entire segment. repne scasb cmp byte ptr es:[di],0 ;If double zero, end of env jne subenvvar_1 ; block. else, loop back. pop di ;Restore DI and exit jmp short subenvvar_exit ; ;Environment variable found. Substitute into alias. ; subenvvar_2: mov si,es ;DS:SI points to env string mov ds,si ;ES:DI points to internal buff mov si,cs mov es,si mov si,di ;Copy pointer to var contents. pop di ;Restore ptr to internal buff subenvvar_3: lodsb ;Move environment pointer past cmp al,"=" ; the equals sign. jne subenvvar_3 subenvvar_4: lodsb ;Move pointer to first cmp al," " ; non-space character. jb subenvvar_4 subenvvar_5: or al,al ;See if at the end of variable je subenvvar_exit stosb ;Save character in command lodsb ;Get next character dec ah ;Dec buffer size count. jne subenvvar_5 ;If buffer not full, continue subenvvar_exit: pop cx ;Restore alias length pop si ;Restore alias pointer pop es ;Restore segment registers pop ds pop dx ret subenvvar endp ;----------------------------------------------------------------------------- ; SUBKEY searches the alias list for a key substitution ; Entry: AL - extended key code ; Exit: CF - clear if key found, set if not found ; DX - offset address of matching entry in alias list (if CF = 0) ; CX - length of matching entry (if CF = 0) ;----------------------------------------------------------------------------- subkey proc near push bx push di push si push ds push es xor ah,ah ;Indicate extended code. les di,cs:[aliaslist_ptr] ;Get pointer to alias list. subkey_1: mov dx,es:[di] ;Get next entry offset cmp dx,-1 ;See if at the end of the list je subkey_notfound cmp es:[di+4],ax ;Check for key code. je subkey_found ;If found, exit loop subkey_2: add di,dx ;Else, point to next entry. jmp short subkey_1 ; ;Copy alias into internal buffer. ; subkey_found: mov si,di ;Load SI with alias pointer mov ax,es mov ds,ax ;Point DS to alias list seg xor cx,cx mov cl,ds:[si+3] ;Get size of alias call getalias ;Get alias from list mov dx,si ;Copy pointer to buffer clc ;Set key found flag subkey_exit: pop es pop ds pop si pop di pop bx ret subkey_notfound: stc ;Set key not found flag jmp subkey_exit subkey endp ;----------------------------------------------------------------------------- ; SEARCHALIAS searches the alias list for a matching alias. ; Entry: DS:SI - pointer to alias ; ES - segment of installed code ; CX - length input buffer ; Exit: CF - clear if alias found ; ES:DI - pointer to matching entry in alias list, if CF is clear ;----------------------------------------------------------------------------- searchalias proc near push bx ;Save registers push cx push si xor bx,bx searchalias_1: lodsb ;Compute the length of the or al,al ; length of the alias by je searchalias_2 ; finding the next space. cmp al," " ;Allow zero byte in alias jbe searchalias_3 ; for function key labels. searchalias_2: inc bx loop searchalias_1 searchalias_3: pop si les di,es:[aliaslist_ptr] ;Get pointer to alias list. mov cx,bx ;Get length of alias searchalias_4: mov bx,es:[di] cmp bx,-1 ;See if at the end of the list je searchalias_notfound cmp es:[di+2],cl ;Compare lengths jne searchalias_5 push cx ;Save size and starting push di ; pointers. push si add di,4 ;Point to start of alias field. repe cmpsb ;Compare alias to input string pop si pop di pop cx je searchalias_6 ;If found, exit loop searchalias_5: add di,bx ;Else, point to next entry. jmp short searchalias_4 searchalias_6: clc ;Set alias found flag searchalias_exit: pop cx pop bx ret searchalias_notfound: stc jmp short searchalias_exit searchalias endp ;----------------------------------------------------------------------------- ; SCAN4CHAR scans a string to find the first character. ; Entry: SI - pointer to ASCII string ; BL - 0 = find next char, 1 = find next space ; CX - file length ; Exit: AL - first nonspace character ; CF - set if carriage return found ;----------------------------------------------------------------------------- scan4char proc near assume ds:nothing,es:nothing scan4loop: jcxz scan4_eol ;See if at the end of the file. lodsb dec cx ;Decrement file length counter. cmp al,13 ;Check for carriage return. jne scan4_1 scan4_eol: stc jmp short scan4_exit1 scan4_1: or bl,bl ;Check if searching for space jne scan4_2 ; or character. cmp al," " ;Check for space or other jbe scan4loop ; 'white' characters. jmp short scan4_exit scan4_2: cmp al," " ;Check for characters. ja scan4loop scan4_exit: clc scan4_exit1: ret scan4char endp ;---------------------------------------------------------------------------- ; CMD_INPUT replaces DOS' 0Ah text input function. ;---------------------------------------------------------------------------- cmd_input proc near push ds ;Save DS xor ax,ax ;Then zero it mov ds,ax mov ax,ds:[0485h] ;Get number of scan lines cmp ax,cs:[points] ; per character and branch je cmd1 ; if it hasn't changed mov cs:[points],ax ;Record new number of scan mov ax,ds:[0460h] ; lines per character and mov cs:[cursor_mode],ax ; cursor mode cmd1: pop ds ;Restore DS call set_cursor ;Set cursor mode mov ah,15 ;Get video page and columns int 10h dec ah ;Calculate max column number mov cs:[columns],ah ;Save it mov ax,ds ;Point ES:DI to buffer mov es,ax mov di,dx add di,2 mov si,dx ;Point DS:SI to character count inc si mov byte ptr [si],0 ;Zero initial count mov cs:[bufferptr],1 ;Set initial index value cld ;Clear DF ; ;Wait for a keycode to appear in the keyboard buffer. ; getkey: mov ah,0Bh ;Check buffer for keycode int 21h or al,al ;Anything there? jne getchar ;Yes, then go get it int 28h ;No, then execute interrupt 28h jmp getkey ;Loop back for another try ; ;Read the keycode and process it if it's not an extended code. ; getchar: mov ah,8 ;Read character from buffer int 21h or al,al ;Is it an extended code? je excode ;Yes, then branch cmp al,8 ;Backspace key? jne getc1 ;No, then branch call backspace ;Rub out a character jmp getkey ;Return to loop getc1: cmp al,9 ;Tab key? jne getc2 ;No, then branch call tab ;Tab to next tab boundary jmp getkey ;Return to loop getc2: cmp al,27 ;ESC key? jne getc3 ;No, then branch call clear_line ;Yes, then clear input line mov cs:[cmd_ptr],0 ;Zero current command pointer jmp getkey getc3: cmp al,7Fh ;Ctrl-Backspace? jne getc4 ;No, then branch call ctrl_bs ;Yes, then delete word jmp getkey getc4: cmp al,13 ;ENTER key? je enter ;Yes, then branch call printchar ;No, then print the character getc5: jmp getkey enter: call eol ;Place cursor at end-of-line mov byte ptr es:[di],13 ;Insert carriage return code mov ah,2 ;Advance to next line mov dl,13 int 21h get_exit: ret ; ;Process extended keycodes. ; excode: mov ah,8 ;Read extended code int 21h cmp al,3Bh ;See if below F1 jb excode3 cmp al,71h ;See if above Alt-F10 ja excode3 cmp al,54h ;See if above Shift-F1 jae excode1 cmp al,44h ;See if above F10 ja excode3 excode1: call subkey ;Scan alias list for match jc getkey ;Exit if no match found push cx push dx call clear_line ;Clear command line pop dx pop cx excode2: push si mov si,dx ;Copy offset address into SI mov al,byte ptr cs:[si] ;Get next character pop si cmp al,13 ;Exit and execute command je enter ; on carriage return inc dx push cx push dx call printchar ;Print it pop dx pop cx jc getc5 loop excode2 ;Loop until done jmp getkey ;Return to input loop excode3: push es ;Save buffer address push di mov cx,cs ;Point ES:DI to list of mov es,cx ; supported keycodes mov di,offset exkeys mov cx,offset exkeys_end - offset exkeys repne scasb ;Scan list pop di ;Clear the stack pop es jne excode4 ;Ignore if key not found shl cx,1 ;Convert CX to address add cx,offset ex_entry push bx ;Save page number in BH mov bx,cx ;Get entry address from table mov ax,cs:[bx] pop bx ;Restore BH call ax ;Call handling routine excode4: jmp getkey ;Return to input loop cmd_input endp ;------------------------------------------------------------------------------ ; PREV_CMD outputs the previous command in the command stack. ;------------------------------------------------------------------------------ prev_cmd proc near mov dx,cs:[cmd_ptr] ;Get current stack index cmp dx,cs:[cmdstack_size] ;Exit if at top of command je prev_exit ; stack or dx,dx ;Branch if not at bottom of jnz prev1 ; command stack ; ;Copy the current contents of the command line to the search buffer. ; mov cl,[si] ;Get count of characters on xor ch,ch ; command line in CX inc cx push es ;Save registers push di push si mov ax,cs ;Point ES:DI to search text mov es,ax ; buffer mov di,offset command_tail rep movsb ;Copy command line text pop si ;Restore registers pop di pop es ; ;Search for the previous command and output it. ; prev1: inc dx ;Increment stack index mov ax,cs:[next_ptr] ;Get stack base index sub ax,dx ;Calculate address of previous cmp ax,0 ; command jge prev2 add ax,cs:[cmdstack_size] prev2: mov cl,7 ;Calculate offset address of shl ax,cl ; the command add ax,cs:[cmdstack_base] cmp byte ptr cs:[command_tail],0 ;Output command if there is je prev3 ; no search criterion call check_string ;Compare strings jz prev3 ;Output command if the strings cmp dx,cs:[cmdstack_size] ; match jne prev1 ret ;Exit if at top of stack prev3: push si ;Save SI mov si,ax ;Transfer address to SI cmp byte ptr cs:[si],0 ;Valid command? pop si ;Restore SI je prev_exit ;No, then ignore keypress mov cs:[cmd_ptr],dx ;Save new command pointer call write_command ;Output the command string prev_exit: ret prev_cmd endp ;------------------------------------------------------------------------------ ; NEXT_CMD outputs the next command in the command stack. ;------------------------------------------------------------------------------ next_cmd proc near mov dx,cs:[cmd_ptr] ;Get current stack index or dx,dx ;Exit if it's zero jz next_exit next1: dec dx ;Decrement stack index mov cs:[cmd_ptr],dx ;Save command pointer or dx,dx ;Clear line and exit if jz next3 ; the result is zero mov ax,cs:[next_ptr] ;Get stack base index sub ax,dx ;Calculate address of next cmp ax,0 ; command jge next2 add ax,cs:[cmdstack_size] next2: mov cl,7 ;Calculate offset address of shl ax,cl ; command add ax,cs:[cmdstack_base] cmp byte ptr cs:[command_tail],0 ;Output command if there is je next4 ; no search criterion call check_string ;Compare strings jz next4 ;Output command if the strings jmp next1 ; match next3: call clear_line cmp byte ptr cs:[command_tail],0 je next_exit mov ax,offset command_tail next4: call write_command ;Output the command string next_exit: ret next_cmd endp ;------------------------------------------------------------------------------ ; CHECK_STRING compares the string in the search buffer with another string. ; Entry: AX - string address ; Exit: ZF - set if strings are equivalent, clear if they are not ;------------------------------------------------------------------------------ check_string proc near push ds ;Save registers push si push es push di mov cx,cs ;Point DS and ES to mov ds,cx ; code segment mov es,cx mov si,offset command_tail ;Point DS:SI to text in mov cl,[si] ; search buffer xor ch,ch inc si mov di,ax ;Point DI to other string inc di ; repe cmpsb ;Compare strings pop di ;Restore registers pop es pop si pop ds ret check_string endp ;------------------------------------------------------------------------------ ; PRINT_STRING writes an ASCII string to the command line. ; Entry: DS:SI - string address ; CX - number of characters ;------------------------------------------------------------------------------ print_string proc near jcxz ps_exit ;Exit if no characters push dx cld mov ah,2 ;Print the character ps1: lodsb ;Get a byte mov dl,al ;Transfer it to DL int 21h ;Output character loop ps1 ;Loop until done pop dx ps_exit: ret print_string endp ;------------------------------------------------------------------------------ ; WRITE_COMMAND outputs a command string. ; Entry: AX - string offset address ; Exit: AL - character after string ;------------------------------------------------------------------------------ write_command proc near push ax ;Save address call clear_line ;Clear input line pop ax ;Retrieve string address push ds ;Save DS and SI push si push cs ;Point DS to string segment pop ds mov si,ax ;Point SI to the string mov cl,[si] ;Get string length xor ch,ch mov byte ptr es:[di-1],cl ;Store string length inc si ;Advance SI to string text write1: mov ah,2 ;Print one character mov dl,[si] int 21h movsb ;Transfer character to buffer inc cs:[bufferptr] ;Advance pointer loop write1 ;Loop until done lodsb ;Get first character after string pop si ;Restore registers pop ds ret write_command endp ;------------------------------------------------------------------------------ ; TOGGLE_INS toggles the insert flag. ;------------------------------------------------------------------------------ toggle_ins proc near xor cs:[insert_flag],1 ;Toggle insert flag call set_cursor ;Set cursor mode ret toggle_ins endp ;------------------------------------------------------------------------------ ; TAB tabs to the next tab boundary. ;------------------------------------------------------------------------------ tab proc near mov al,cs:[bufferptr] ;Calculate number of dec al ; spaces to insert for xor ah,ah ; soft tab mov bl,8 div bl mov cx,8 sub cl,ah tab1: push cx ;Print spaces mov al,32 call printchar pop cx jc tab_exit loop tab1 tab_exit: ret tab endp ;------------------------------------------------------------------------------ ; BACKSPACE deletes the character left of the cursor. ;------------------------------------------------------------------------------ backspace proc near cmp cs:[bufferptr],1 ;At beginning of command line? je bs_exit ;Yes, then ignore it mov cl,[si] ;Get count sub cl,cs:[bufferptr] ;Calculate distance to end-of-line inc cl xor ch,ch push cx ;Save it jcxz bs1 ;Branch if at end-of-line ; ;Shift all characters right of the cursor in the buffer one slot left. ; push si ;Save SI and DI push di mov si,di ;Position them for shifts dec di rep movsb ;Shift characters right of cursor pop di ;Restore registers pop si ; ;Display the new string and update input parameters. ; bs1: call move_left ;Move cursor left bs2: pop cx ;Retrieve shift count push dx ;Save cursor position push si ;Save SI mov si,di ;Point SI to new part of string call print_string ;Print the new part mov ah,2 ;Blank the last character mov dl,32 int 21h pop si ;Restore registers pop dx ;Restore cursor address mov ah,2 ;Reset the cursor int 10h dec byte ptr [si] ;Decrement character count bs_exit: ret backspace endp ;------------------------------------------------------------------------------ ; PRINTCHAR writes a new character to the input buffer and echoes it. ; Entry: AL - character to print ; Exit: CF clear if character printed ; CF set if buffer full ;------------------------------------------------------------------------------ printchar proc near cmp cs:[insert_flag],0 ;Insert state on? jne print3 ;Yes, then branch ; ;Print a character in overstrike mode. ; mov cl,[si] ;Get count cmp cl,cs:[bufferptr] ;End-of-line? jae print2 ;No, then branch mov cl,[si-1] ;Get maximum length sub cl,[si] ;Subtract current length cmp cl,1 ;Buffer full? je beep ;Yes, then branch print1: inc byte ptr [si] ;Increment count print2: stosb ;Deposit new character mov ah,2 ;Then print it mov dl,al int 21h inc cs:[bufferptr] ;Advance buffer pointer print_exit: clc ;Clear CF and exit ret beep: mov ax,0E07h ;Print ASCII 7 thru BIOS int 10h stc ret ; ;Print a character in insert mode. ; print3: mov cl,[si-1] ;Get maximum length sub cl,[si] ;Subtract current count cmp cl,1 ;Buffer full? je beep ;Yes, then branch mov cl,[si] ;Get count cmp cl,cs:[bufferptr] ;End-of-line? jb print1 ;Yes, then branch sub cl,cs:[bufferptr] ;Calculate number of shifts inc cl xor ch,ch push cx ;Save shift count push si ;Save SI add di,cx ;Position DI to end-of-line mov si,di ;Position SI just before it dec si std ;Set DF for now rep movsb ;Make room for new character cld ;Clear DF pop si ;Restore SI mov es:[di],al ;Deposit new character mov ah,3 ;Get cursor position int 10h pop cx ;Retrieve shift count inc cx ;Increment it push dx ;Save cursor position push si ;Save SI mov si,di ;Point SI to current location call print_string ;Print new part of string pop si ;Restore SI and DX pop dx mov ah,2 ;Reset cursor position int 10h inc byte ptr [si] ;Add to character count call move_right ;Move cursor right jmp print_exit printchar endp ;------------------------------------------------------------------------------ ; DELETE deletes the character at the cursor. ;------------------------------------------------------------------------------ delete proc near mov cl,[si] ;Get count cmp cl,cs:[bufferptr] ;End-of-line? jb del2 ;Yes, then ignore keypress sub cl,cs:[bufferptr] ;Calculate number of shifts xor ch,ch ;Byte to word in CX push cx ;Save shift count jcxz del1 ;Branch if no shifts push si ;Save SI and DI push di mov si,di ;Position registers for shift inc si rep movsb ;Shift chars right of cursor pop di ;Restore registers pop si del1: mov ah,3 ;Get cursor position int 10h jmp bs2 ;Exit thru BACKSPACE routine del2: ret delete endp ;------------------------------------------------------------------------------ ; CTRL_BS deletes the word at the cursor. ;------------------------------------------------------------------------------ lesschars dw ? ;Count of chars deleted shiftcount dw ? ;Count of chars shifted ctrl_bs proc near mov cl,[si] ;Exit now if there is nothing xor ch,ch ; on the command line or cx,cx jnz cbs1 cbs_exit: ret cbs1: cmp cs:[bufferptr],1 ;Exit if the cursor is at the je cbs3 ; at the end of the command cmp cl,cs:[bufferptr] ; line or if it is under a jb cbs_exit ; space; otherwise, move to cmp byte ptr [di],32 ; the beginning of the je cbs_exit ; current word cmp byte ptr [di-1],32 je cbs3 cbs2: push cx ;Save CX call ctrl_left ;Move to start of word pop cx ;Restore CX cbs3: inc cx ;Calculate max number of push cx ; characters to search mov dl,cs:[bufferptr] ; looking for the next xor dh,dh ; word or end-of-line sub cx,dx push di ;Save DI cbs4: inc di ;Search until DI addresses cmp byte ptr [di],32 ; either the first character je cbs5 ; in the next word or the cmp byte ptr [di-1],32 ; end of the command line je cbs6 cbs5: loop cbs4 cbs6: mov dx,di ;Save final value of DI pop di ;Restore DI pop cx ;Retrieve count mov cs:[lesschars],dx ;Calculate number of chars to sub cs:[lesschars],di ; be deleted sub cx,dx ;Then calculate how many chars add cx,si ; must be shifted mov cs:[shiftcount],cx jcxz cbs7 ;Branch if no shift push si ;Save registers push di mov si,dx ;Point DS:SI to next word rep movsb ;Delete current word pop di ;Restore registers pop si cbs7: mov cx,cs:[lesschars] ;Update character counter sub [si],cl ; in input buffer mov ah,3 ;Save the current cursor int 10h ; position on the stack push dx push si ;Update the text on the mov si,di ; command line mov cx,cs:[shiftcount] call print_string pop si mov cx,cs:[lesschars] cbs8: mov ah,2 ;Print as many spaces as mov dl,32 ; there were characters int 21h ; deleted loop cbs8 pop dx ;Restore cursor position mov ah,2 ; and exit int 10h ret ctrl_bs endp ;------------------------------------------------------------------------------ ; CTRL_END deletes command line text from the cursor to the end of the line. ;------------------------------------------------------------------------------ ctrl_end proc near mov cl,[si] ;Exit if already at end cmp cl,cs:[bufferptr] ; of line jb ce_exit sub cl,cs:[bufferptr] ;Calculate number of chars xor ch,ch ; to be deleted inc cx sub [si],cl ;Update count in input buffer push cx mov ah,3 ;Get and save cursor position int 10h pop cx push dx ce1: mov ah,2 ;Print as many spaces as mov dl,32 ; there are characters int 21h ; to delete loop ce1 mov ah,2 ;Reset cursor position and pop dx ; exit int 10h ce_exit: ret ctrl_end endp ;------------------------------------------------------------------------------ ; MOVE_LEFT moves the cursor one character left. ;------------------------------------------------------------------------------ move_left proc near cmp cs:[bufferptr],1 ;At beginning of line? je left2 ;Yes, then ignore keypress mov ah,3 ;Get cursor position int 10h dec dl ;Decrement it by 1 cmp dl,0FFh jne left1 mov dl,cs:[columns] ;Decrement row number by 1 dec dh ; if cursor wraps around left1: mov ah,2 ;Set new position int 10h dec di ;Decrement pointers dec cs:[bufferptr] left2: ret move_left endp ;------------------------------------------------------------------------------ ; MOVE_RIGHT moves the cursor one character right. ;------------------------------------------------------------------------------ move_right proc near mov cl,[si] ;Get count cmp cl,cs:[bufferptr] ;End-of-line? jb rt2 ;Yes, then ignore keypress mov ah,3 ;Get cursor position int 10h inc dl ;Increment column number cmp dl,cs:[columns] ;Increment row number if jna rt1 ; cursor wraps around xor dl,dl inc dh rt1: mov ah,2 ;Position cursor int 10h inc di ;Advance pointers inc cs:[bufferptr] rt2: ret move_right endp ;------------------------------------------------------------------------------ ; CTRL_LEFT moves the cursor one word left. ;------------------------------------------------------------------------------ ctrl_left proc near call move_left ;Move one character left cmp cs:[bufferptr],1 ;Beginning of line? je cl_exit ;Yes, then exit cmp byte ptr es:[di],32 ;Loop back if current char je ctrl_left ; is a space cmp byte ptr es:[di-1],32 ;Loop back if char to the jne ctrl_left ; left is not a space cl_exit: ret ctrl_left endp ;------------------------------------------------------------------------------ ; CTRL_RIGHT moves the cursor one word right. ;------------------------------------------------------------------------------ ctrl_right proc near call move_right ;Move one character right mov cl,[si] ;End-of-line? cmp cl,cs:[bufferptr] ;Yes, then exit jb cr_exit cmp byte ptr es:[di],32 ;Loop back if current char je ctrl_right ; is a space cmp byte ptr es:[di-1],32 ;Loop back if char to the jne ctrl_right ; left is not a space cr_exit: ret ctrl_right endp ;------------------------------------------------------------------------------ ; HOME relocates the cursor to the beginning of the command line. ;------------------------------------------------------------------------------ home proc near mov cl,cs:[bufferptr] ;Get position pointer dec cl ;Calculate distance from start xor ch,ch jcxz home_exit ;Exit if already there home1: push cx ;Save count call move_left ;Move left one space pop cx ;Retrieve count loop home1 ;Loop until done home_exit: ret home endp ;------------------------------------------------------------------------------ ; EOL advances the cursor to the end of the command line. ;------------------------------------------------------------------------------ eol proc near mov cl,[si] ;Get count cmp cl,cs:[bufferptr] ;Already at end? jb eol_exit ;Yes, then exit sub cl,cs:[bufferptr] ;Calculate distance from end inc cl xor ch,ch ;Byte to word in CX eol1: push cx ;Advance right CX times call move_right pop cx loop eol1 eol_exit: ret eol endp ;------------------------------------------------------------------------------ ; CLEAR_LINE clears the command line. ; Entry: BH - current video page ;------------------------------------------------------------------------------ clear_line proc near mov cl,[si] ;Get count xor ch,ch jcxz cline2 ;Exit if no characters push cx ;Save count call home ;Home the cursor mov ah,3 ;Get cursor position int 10h pop cx ;Restore CX push dx ;Save cursor address mov ah,2 ;Print ASCII spaces mov dl,32 cline1: int 21h loop cline1 mov ah,2 ;Home cursor again pop dx int 10h mov byte ptr [si],0 ;Reset count cline2: ret clear_line endp ;------------------------------------------------------------------------------ ; CMD_RECORD records the latest command in the command stack. ; Entry: DS:DX - input buffer address ;------------------------------------------------------------------------------ cmd_record proc near mov si,dx ;Point SI to input buffer mov al,[si+1] ;Get length of input string cmp al,cs:[minlength] ;Is the length zero? jb cmd_exit ;Yes, then exit now inc si ;Advance SI to count byte push cs ;Point ES to command stack pop es ; segment mov di,cs:[next_ptr] ;Get command stack pointer mov cl,7 ;Convert it to offset address shl di,cl add di,cs:[cmdstack_base] mov cl,al ;Transfer string length to CL inc cl ;Increment for count byte xor ch,ch ;Byte to word in CX cld ;Clear DF rep movsb ;Copy string to command stack inc cs:[next_ptr] ;Update pointer mov ax,cs:[cmdstack_size] cmp cs:[next_ptr],ax ;Wrap around if necessary jne cmdrec1 mov cs:[next_ptr],0 cmdrec1: mov cs:[cmd_ptr],0 ;Zero current command pointer cmd_exit: ret cmd_record endp ;------------------------------------------------------------------------------ ; SET_CURSOR sets the cursor mode based on the state of the insert flag. ;------------------------------------------------------------------------------ set_cursor proc near cmp cs:[insert_flag],0 ;Test state of insert flag je setc1 ;Branch if not set mov cx,cs:[cursor_mode] ;Raise top by 2 scan lines sub ch,2 jns setc2 ;Exit if it wraps around ret setc1: mov cx,cs:[cursor_mode] ;Set default cursor setc2: mov ah,1 ;Set cursor mode int 10h ret set_cursor endp ;============================================================================ ; MUXINT processes calls to interrupt 2Fh ; Entry: AH - Device ID ; Exit: AL - 0FFh if AH = Alias device ID. Unchanged otherwise. ; ES - Code segment if AH = Alias device ID. Unchanged otherwise. ;============================================================================ muxint proc far assume cs:code,ds:nothing,es:nothing cmp ah,cs:[multiplex_id] ;Check for program ID je muxint_1 ;Its us, indicate installed. jmp cs:[int2fh] ;else pass the call on muxint_1: mov al,-1 ;Indicate Alias installed push cs ;ES = installed code segment pop es iret muxint endp even ;Align stack on word boundry end_of_resident = $ ;---------------------------------------------------------------------------- ; Start of non-resident code. ;---------------------------------------------------------------------------- final_install: rep movsb ;Copy alias list mov di,cmdstack_base ;Initialize command stack mov cx,cmdstack_size ; area with leading zeroes jcxz tsr ;Branch if size is zero xor al,al cld final_loop: stosb add di,127 loop final_loop tsr: mov ax,3100h ;Terminate and stay resident int 21h ;---------------------------------------------------------------------------- ; Non-resident data. ;---------------------------------------------------------------------------- alrdy_installed db 0 ;Installed flag other_seg dw 0 ;Segment of installed code databuff_seg dw 0 ;Segment of data buffer. alias_buffer dw 512 ;Extra buffer for alias list. aliaslist_end dw 0 ;Offset of end of the list. alias_inlist db 0 ;Flag used in alias list append infomsg1 db "ALIAS uninstalled$" infomsg2 db 13,10,9,"Command stack size: $" infomsg3 db 13,10,9,"Minimum stacked command length: $" infomsg4 db 13,10,9,"Bytes free in alias buffer: $" infomsg5 db 13,10,9,"Alias translation is $" infomsg5d db "disabled",13,10,"$" infomsg5e db "enabled",13,10,"$" infomsg6 db 13,10,9,"FUNCTION KEY DEFINITIONS$" infomsg7 db 13,10,9,"ALIAS DEFINITIONS$" infomsg8 db 13,10,"For help type ALIAS ?$" infomsg9 db 13,10,"Can",39,"t find Master Env. block$" filemsg1 db 13,10,"Error in line $" ;File identification message. filemsg2 db " of file: " filenam_field db 78 dup (0) ;Name of current entry file. errmsg0 db "Need DOS 2.0 or greater$" errmsg1 db "ALIAS not installed$" errmsg2 db 13,10,"Syntax: ALIAS [alias [command]] " db "[/F filename] [/S nn] [/U]",13,10 db 14 dup (" ") db "[/B nn] [/D] [/E] [/L] [/M]",13,10,10 db 9,"ALIAS alias command",13,10 db 9,"ALIAS [fn] command",13,10,10 db 9,"/B = Buffer size",13,10 db 9,"/D = Disable alias translation",13,10 db 9,"/E = Enable alias translation",13,10 db 9,"/F = Filename of command file",13,10 db 9,"/L = List aliases",13,10 db 9,"/M = Minimum command length to stack",13,10 db 9,"/S = Size of command stack",13,10 db 9,"/U = Uninstall",13,10,"$" errmsg3 db "Can",39,"t uninstall$" errmsg4 db "Can",39,"t change parameter after installation$" errmsg5 db "Illegal number$" errmsg6 db "Can",39,"t find alias file$" errmsg7 db "Can",39,"t find COMMAND.COM$" errmsg8 db "Not enough memory$" errmsg9 db "Alias list full$" errmsg10 db "List and stack too large$" errmsg11 db "Invalid key assignment$" errmsg12 db "Number too big$" errmsg13 db "Alias not in list$" errmsg14 db "Error using Int 2Fh$" endmsg db 13,10,"$" shiftmsg db "S-$" altmsg db "A-$" ctlmsg db "C-$" file_linecount dw 0 ;Line number being processed. caps_flag db 0 param_found db 0 ;Cmd line parameter found flag append_cr db 0 ;Append cr to alias flag cmdcom_name db "COMMAND" ;Name of command.com cmd_switches db "sfeldbum*/" ;Letters of valid commands. cmd_switch_end = $ cmd_jmp_tbl dw offset setstacksize ;This jump table is used to dw offset loadaliasfile ; call the routines that dw offset enablealias ; process the command line dw offset listalias ; arguments dw offset disablealias dw offset setlistbuffer dw offset remove dw offset minstacklen dw offset comment_line ;Comments can be indicated by dw offset comment_line ; a /* or a //. ;---------------------------------------------------------------------------- ; Initialization routine. ;---------------------------------------------------------------------------- initialize proc near assume cs:code,ds:code,es:code cld mov ah,30h ;Get DOS version int 21h xchg al,ah ;Swap major, minor numbers mov dx,offset errmsg0 ;Bad DOS version cmp ah,2 ;Run if DOS 2.0 or greater. jb jmp_disp_error mov dos_version,ax ;Save version number mov ax,max_code_size ;Get size of installed code. mov bx,ax shl ax,1 ;Convert to bytes shl ax,1 shl ax,1 shl ax,1 mov sp,ax ;Move stack pointer sub ax,512 ;Save room for stack mov aliaslist_size,ax ;Mark end of alias list mov ah,4ah ;Reduce memory allocation int 21h mov bx,filebuf_size ;Get size of file buffer, mov ah,48h ;Allocate memory block int 21h mov dx,offset errmsg8 ;Not enough memory msg jc jmp_disp_error mov databuff_seg,ax ;Save segment to file buffer. mov ax,offset end_of_code ;Initialize alias list mov word ptr [aliaslist_ptr],ax ; pointers. mov ax,cs mov word ptr [aliaslist_ptr+2],ax les di,aliaslist_ptr ;Initialize alias list mov ax,-1 ; by writing a -1 as stosw ; an end flag. mov aliaslist_end,di ; ;See if a copy is already resident in memory. If > DOS 3.0, use int 2Fh. ; mov byte ptr [main+2],0 ;Initialize fingerprint cmp dos_version,300h ;See if DOS 3.0 or later jb find_copy1 ;No, search the old way. mov cx,16 ;Try 16 different IDs. find_copy: xor ax,ax mov es,ax mov ah,multiplex_id ;Load ID. Use Int 2Fh to int 2fh ; reach installed code so or al,al ; that we are compatible jne find_copy0 ; with 386 memory managers. push cs pop es ;If AL not changed, ALIAS not jmp short find_copy4 ; installed. find_copy0: push cx call cmpheader ;See if really Alias by pop cx ; comparing file headers. je find_copy3 inc multiplex_id ;ID used by another program. loop find_copy ; Change and try again. mov dx,offset errmsg14 ;All IDs taken, print error jmp_disp_error: jmp disp_error ; msg and exit. ; ;For DOS 2.x find the installed code the old fashioned way by scanning ;the memory control blocks. ; find_copy1: xor bx,bx ;zero BX for start mov ax,cs ;keep CS value in AX find_copy2: inc bx ;increment search segment value mov es,bx assume es:nothing cmp ax,bx ;not installed if current je find_copy4 ; segment is found. call cmpheader jne find_copy2 ;loop back if not found find_copy3: inc alrdy_installed ;Set installed flag find_copy4: mov other_seg,es ;Save seg of installed code ; ;Copy the command line to the file buffer to treat as a one line file. ; mov ax,databuff_seg ;Get segment of file buffer. mov es,ax ;Treat the command line as xor di,di ; a 1 line file. mov si,offset command_tail xor cx,cx or cl,[si] ;Get command line length je parse_line_end ;If zero, skip parse routine inc si ;Copy command line into file inc cx ; buffer. push cx rep movsb pop cx ;CX = file size. xor si,si ;Point SI to start of buffer push es pop ds ;Set DS to file buffer seg assume ds:nothing mov es,cs:[other_seg] ;Set ES to installed code ; ;Parse command line and command files. ; parse_line_loop: xor bl,bl call scanline ;Get 1st character jc parse_2 ;If carriage return, skip line cmp al,"/" ;Compare character to switch. je parse_switch_found cmp al,"?" ;See if help character mov dx,offset errmsg2 ;Command not found msg je disp_error call setkey ;Must be alias definition jc disp_error mov param_found,1 ;Set parameter found flag jmp short parse_2 ;Return to parse loop parse_switch_found: mov param_found,1 ;Set parameter found flag lodsb ;Get command line switch dec cx cmp al,'A' ;Convert to lower case if jb parse_1 ; necessary. cmp al,'Z' ja parse_1 or al,20h parse_1: push cx ;Scan the list of allowable push es ; command switches. If switch push cs ; found, use its position for pop es ; an index into the list of mov di,offset cmd_switches ; routines. mov cx,offset cmd_switch_end - offset cmd_switches mov bx,offset cmd_switch_end - offset cmd_switches - 1 repne scasb mov ax,cx ;Copy index into list pop es pop cx mov dx,offset errmsg2 ;Command not found msg jne disp_error sub bx,ax ;Compute offset into list shl bx,1 ;Convert to word offset add bx,offset cmd_jmp_tbl ;Add the start addr of table. call cs:[bx] ;Call command routine. jc disp_error ;If error terminate parse. parse_2: jcxz parse_line_end ;If at file end, exit parse. jmp short parse_line_loop ; ;See if installed. If not, install. ; parse_line_end: cmp cs:[param_found],1 ;See if any parameters found je init2 ;If already installed and cmp cs:[alrdy_installed],0 ; no parameters on the je init2 ; command line, default to mov es,cs:[other_seg] ; showing program information call listalias init2: mov ah,49h ;Release memory block used mov es,cs:[databuff_seg] ; for file buffer. int 21h push cs pop ds assume ds:code mov word ptr databuff_seg,0 ;Indicate file buff released cmp alrdy_installed,0 ;If not already installed, je install ; jump to install routine. exit: mov ax,4C00h ;Terminate with RC = 0 int 21h ; ;Display error message. ; assume ds:nothing disp_error: xor ax,ax ;If file buffer still or ax,databuff_seg ; allocated, deallocate it. jz disp_error0 mov ah,49h ;Release memory block used mov es,ax ; for file buffer. int 21h disp_error0: push cs pop ds assume ds:code cmp byte ptr filenam_field,0 je disp_error1 ;If processing a file, print push dx ; a message informing the mov dx,offset filemsg1 ; user the filename being call printmsg ; processed and the line mov ax,file_linecount ; that the error occured. call hex2asc mov dx,offset filemsg2 call printmsgcr pop dx disp_error1: call printmsgcr ;print string mov ax,4c01h ;Terminate with RC = 1 int 21h ; ;Install routine. Find segment of COMMAND.COM, hook into int 21h, 2Fh and TSR. ; assume ds:code install: mov dx,offset program ;Display copyright message call printmsg push ds ;Save DS xor ax,ax ;Then zero it mov ds,ax mov cs:[points],ax ;Record number of scan lines mov ax,ds:[0460h] ; per character and cursor mov cs:[cursor_mode],ax ; mode pop ds ;Restore DS mov byte ptr filenam_field,0 ;Don't callout file on error mov ah,52h ;get address of first MCB int 21h mov ax,es:[bx-2] ;point ES to MCB mov cx,20 ;Allow only 20 loops. mcb_loop: mov es,ax cmp byte ptr es:[0],"M" ;check for mcb signature jne mcb_error inc ax ;point AX to memory block cmp ax,es:[1] ;See if this is a PSP block je psp_found mcb_continue: add ax,es:[3] ;Get size of memory block loop mcb_loop mcb_error: mov dx,offset errmsg7 ;Can't locate command.com PSP jmp disp_error psp_found: cmp dos_version,0a00h ;If OS/2, use DOS 3.3 method. jae psp_found_1 cmp dos_version,0400h ;If DOS 4.00 or greater, jb psp_found_1 ; COMMAND.COM may not be the push ds ; first program loaded. Look mov si,offset cmdcom_name ; at the name of the program mov di,8 ; stored in the last 8 bytes mov cx,7 ; of the memory control repe cmpsb ; block. If the string pop ds ; "COMMAND" isn't found, keep jne mcb_continue ; looking. psp_found_1: mov cmdcom_psp,ax ;Save segment of cmd.com PSP mov es,ax mov bx,es:[2ch] ;Get seg of master environment mov master_env,bx dec bx mov es,bx cmp byte ptr es:[0],"M" ;See if valid memory block je psp_found_4 mov dx,ax ;Save COMMAND PSP segment dec ax ;Point back to mcb mov es,ax psp_found_2: add ax,es:[3] ;Get size of memory block inc ax cmp es:[1],dx ;See if owned by CMD.COM je psp_found_3 mov es,ax loop psp_found_2 mov dx,offset infomsg9 ;Indicate can't find env call printmsgcr xor ax,ax psp_found_3: inc ax mov master_env,ax psp_found_4: ; ;Set up pointers to the cmd stack and to move the alias list to the end of the ;command stack so it takes up less space when ALIAS resident. ; mov di,mystack_ptr ;Get base of internal stack mov work_buff_ptr,di ;Copy ptr to alias buffer add di,128 ;Add size of buffer mov cmdstack_base,di ;Copy for start of cmd stack mov ax,cmdstack_size ;Get size of command stack mov ah,128 ;128 bytes for each entry mul ah add di,ax ;Add to cmd stack for mov si,word ptr aliaslist_ptr ; start of the mov cx,aliaslist_end ; alias list. mov word ptr aliaslist_ptr,di ;Save new pointer. sub cx,si ;Compute size of list. mov dx,di ;See if we have enough room add dx,cx ; for everything in one seg. jnc install_1 mov dx,offset errmsg10 ;Not enough memory, exit. jmp disp_error install_1: add dx,alias_buffer ;Add additional space for list mov aliaslist_size,dx ;Save pointer to end of seg add dx,15 ;Convert memory needed to shr dx,1 ; paragraphs. shr dx,1 shr dx,1 shr dx,1 cmp di,si ;Check for overlap in the move jb install_2 ;If overlap, copy list from std ; the top down to avoid add di,cx ; overwriting the list. add si,cx dec si dec di ; ;Revector interrupts 21h and 2Fh (if necessary). ; install_2: mov ax,3521h ;Get interrupt 21 (DOS) int 21h ; vector. mov word ptr [int21h],bx mov word ptr [int21h+2],es push dx ;Save memory size parameter mov ax,2521h ;Point int 21 to internal mov dx,offset dosint ; routine. int 21h cmp dos_version,300h ;See if we are using Int 2Fh jb install_3 mov ax,352fh ;Get interrupt 2F (MUX) int 21h ; vector. mov word ptr [int2fh],bx mov word ptr [int2fh+2],es mov ax,252fh ;Point int 2F to internal mov dx,offset muxint ; routine. int 21h install_3: pop dx push ds ;ES = DS pop es jmp final_install ;Jump to safe place for move. initialize endp ;----------------------------------------------------------------------------- ; CMPHEADER compares the first 16 bytes of this file with the segment ; pointed to by ES. ; Entry: DS - code segment ; ES - pointer to segment to compare ; Exit: ZF - 0 = segments match. ;----------------------------------------------------------------------------- cmpheader proc near mov si,offset main+2 ;Search this segment for ASCII mov di,si ; fingerprint. mov cx,16 repe cmpsb ret cmpheader endp ;----------------------------------------------------------------------------- ; PRINTMSG prints the message pointed to by DX to the screen. ; Entry: DX - pointer to ASCII message terminated by $ ;----------------------------------------------------------------------------- printmsg proc near assume ds:nothing,es:nothing push ds push cs pop ds assume ds:code mov ah,9 ;Print message int 21h pop ds ret printmsg endp ;----------------------------------------------------------------------------- ; PRINTMSGCR calls PRINTMSG, then appends a carriage return to the message. ; Entry: DX - pointer to ASCII message terminated by $ ;----------------------------------------------------------------------------- printmsgcr proc near assume ds:nothing,es:nothing push dx call printmsg mov dx,offset endmsg call printmsg pop dx ret printmsgcr endp ;----------------------------------------------------------------------------- ; SETSTACKSIZE - Sets the size of the command line stack. ; Entry: DS:SI - points to stack size in ascii ; Exit: CF - Clear if sucessful, Set if error, DX points to error msg. ;----------------------------------------------------------------------------- setstacksize proc near assume ds:nothing,es:nothing xor bl,bl ;Check for installed code call setparameter ;Get num and convert to binary jc setstack_exit ;Check for error mov cs:[cmdstack_size],ax ;Save parameter setstack_exit: ret setstacksize endp ;----------------------------------------------------------------------------- ; SETLISTBUFFER - Sets the size of the additional buffer reserved for alias ; list expansion. ; Entry: DS:SI - points to buffer size in ascii ; Exit: CF - Clear if sucessful, Set if error, DX points to error msg. ;----------------------------------------------------------------------------- setlistbuffer proc near assume ds:nothing,es:nothing xor bl,bl ;Check for installed code call setparameter ;Get num and convert to binary jc setlistbuffer_exit ;Check for error mov cs:[alias_buffer],ax ;Save buffer size parameter setlistbuffer_exit: ret setlistbuffer endp ;----------------------------------------------------------------------------- ; MINSTACKLEN - sets the minimum legth of a command to stack. ; Entry: ES - segment of the installed code ; DS:SI - points to buffer size in ascii ; Exit: CF - Clear if sucessful, Set if error, DX points to error msg. ;----------------------------------------------------------------------------- minstacklen proc near assume ds:nothing,es:nothing mov bl,1 ;Don't check for installed code call asc2bin ;Get num and convert to binary jc minstacklen_exit ;Check for error cmp al,126 jb minstacklen_1 mov dx,offset errmsg12 ;Stack length too big stc jmp short minstacklen_exit minstacklen_1: or al,al ;Make sure min length is not jne minstacklen_2 ; specified at 0. If so, inc al ; change to 1. minstacklen_2: mov es:[minlength],al ;Save minimum length parameter minstacklen_exit: ret minstacklen endp ;----------------------------------------------------------------------------- ; SETPARAMETER - Common code used by the set stack and set buffer and set ; minimum command length routines. ; Entry: DS:SI - points to ascii number ; BL - Flag to indicate check for installed code, BL=0, check. ; Exit: CF - Clear if sucessful, Set if error. ;----------------------------------------------------------------------------- setparameter proc near assume ds:nothing,es:nothing mov dx,offset errmsg4 ;Can't change parameter msg cmp cs:[alrdy_installed],1 ;If already installed don't je setparam_error ; change parameter. call asc2bin setparam_exit: ret setparam_error: stc ;Set error flag. jmp short setparam_exit setparameter endp ;----------------------------------------------------------------------------- ; SETKEY modifies the alias list to add function key definitions. ; Entry: DS:SI - pointer to string identifing the function key ; ES - pointer to segment of installed code ; Exit: CF - clear if successful ;----------------------------------------------------------------------------- setkey proc near assume ds:nothing,es:nothing push es cmp al,"[" ;Determine alias or key je setkey_1 dec si ;Backup before last key inc cx jmp short setkey_5 setkey_1: lodsb ;Get next character dec cx jcxz setkey_badkey mov bx,58 ;Load default F1 keycode or al,20h ;Convert to lower case cmp al,"f" je setkey_3 add bx,25 ;Assume shift F1 keycode cmp al,"s" je setkey_2 add bx,10 ;Assume ctl F1 keycode cmp al,"c" je setkey_2 add bx,10 ;Assume alt F1 keycode cmp al,"a" jne setkey_badkey setkey_2: lodsb ;Get next character dec cx or al,20h ;Convert to lower case cmp al,"f" ;Make sure next key is "f" jne setkey_badkey setkey_3: call asc2bin jc setkey_badkey ;If bad number, exit or ax,ax je setkey_badkey ;Make sure not zero cmp ax,10 ja setkey_badkey ;Make sure less than 10 cmp byte ptr [si-1],"]" ;Check for closing bracket jne setkey_badkey ; if not found, error add bx,ax ;Add in function key number cmp byte ptr [si]," " ;Check to see if a character jbe setkey_4 ; trails the closing bracket. cmp byte ptr [si],"*" ;Check to see if an * is jne setkey_badkey ; appended to the function lodsb ; key assignment. If so, dec cx ; remove key and set flag mov cs:[append_cr],1 ; to append cr to command. setkey_4: sub si,2 ;Back up to keycode. xor bh,bh mov ds:[si],bx ;Save keycode on command line add cx,2 setkey_5: call setalias ;Use SETALIAS to load setkey_exit: pop es ;Restore ptr to installed seg ret setkey_badkey: mov dx,offset errmsg11 ;Bad key assignment msg stc jmp setkey_exit setkey endp ;----------------------------------------------------------------------------- ; SETALIAS modifies the alias list according to command line agruments. ; Entry: DS:SI - pointer to string to be inserted into alias list. ; ES - pointer to segment of installed code. ; Exit: CF - clear if successful ;----------------------------------------------------------------------------- setalias proc near assume ds:nothing,es:nothing push es xor bl,bl ;Find 1st character on call scanline ; command line. jnc setalias_1 ;If at end of line, exit jmp setalias_exit ; routine. setalias_1: ; ;Get length of alias, then search list for matching alias ; dec si ;Backup to before 1st char. inc cx mov byte ptr cs:[alias_inlist],0 ;Assume not in list call searchalias ;Is there already an alias? jc setalias_2 ;No, continue. inc byte ptr cs:[alias_inlist] call delete_aliasent ;Delete entry from list setalias_2: ; ;Append new alias to the end of the list. ; mov bp,di ;Save ptr to end of list. add di,4 ;Move past length fields. push es ;Get max size of alias list. mov es,cs:[other_seg] mov dx,es:[aliaslist_size] pop es ; ;Append alias to list. ; xor ax,ax ;Clear character counter setalias_3: lodsb ;Get byte dec cx ;Decriment buffer counter. jcxz setalias_4 ;If at end of file, exit. cmp al,13 ;See if at end of line. jne setalias_6 ;No, continue. setalias_4: cmp byte ptr cs:[alias_inlist],0 jne setalias_5 ;Was alias in list? jmp setalias_notnfil ;No, incomplete alias specifed setalias_5: jmp setalias_exit ;Yes, alias simply erased. setalias_6: cmp al,' ' ;See if at end of tag. je setalias_8 ;Yes, exit copy loop cmp al,9 ;Check for tab je setalias_8 cmp di,dx ;See if alias list is full jbe setalias_7 ;No, continue jmp setalias_full ;Yes, exit routine setalias_7: stosb ;No, add character to list inc ah ;Inc size of tag jmp short setalias_3 setalias_8: mov es:[bp+2],ah ;Save size of alias ; ;Append command to alias list. ; mov cs:[caps_flag],0 ;Initialize setcaps flag. xor bx,bx ;Find 1st character in call scanline ; command. jc setalias_exit ;If no command, exit xor ah,ah ;Clear character counter setalias_9: cmp al,"%" ;Check for environment var jne setalias_11 ; by checking for % signs. cmp cs:[caps_flag],0 ;If caps flag set capitialize jne setalias_10 ; string before saving. mov bl,ds:[si] ;Get next character cmp bl,"0" ;If numeric, assume this is jb setalias_10 ; a line parameter, not an cmp bl,"9" ; environment variable so jbe setalias_11 ; don't set caps flag. cmp bl,"%" ;Don't let double % signs je setalias_11 ; indicate environment var. setalias_10: not byte ptr cs:[caps_flag] ;Toggle caps flag setalias_11: cmp cs:[caps_flag],0 ;Capitialize environment je setalias_12 ; variables so they will cmp al,"a" ; match when searched for in jb setalias_12 ; the environment block. cmp al,"z" ja setalias_12 and al,0dfh ;Make character uppercase. setalias_12: cmp di,dx ;See if alias list is full ja setalias_full ;Yes, exit routine stosb ;Append character on list inc ah ;Inc character counter. jcxz setalias_13 ;Check for end of file. lodsb ;Get next character dec cx ;Dec file counter. cmp al,13 ;See if carriage return. jne setalias_9 ;If not continue setalias_13: cmp cs:[append_cr],1 ;If flag set, append carrage jne setalias_14 ; return to command. mov al,13 inc ah stosb mov cs:[append_cr],0 ;Clear flag setalias_14: mov es:[bp+3],ah ;Save command size mov word ptr es:[di],-1 ;Set new end of list flag mov ax,di ;Save end pointer to list add ax,2 ;Make room for the end flag. mov cs:[aliaslist_end],ax sub di,bp ;Compute size of entry mov es:[bp],di ;Put size over old end flag. inc cs:[file_linecount] ;Point counter to next line. setalias_exit: clc setalias_exit1: pop es ;Restore ptr to installed seg ret setalias_full: mov dx,offset errmsg9 ;Alias list too large msg. stc jmp short setalias_exit1 setalias_notnfil: mov dx,offset errmsg13 ;Alias not in list. stc jmp short setalias_exit1 setalias endp ;----------------------------------------------------------------------------- ; DELALIASENTRY - Deletes an alias entry ; Entry: DS:SI - pointer to the entry in the alias list to delete ; Exit: CF - clear if successful ;----------------------------------------------------------------------------- delete_aliasent proc near push cx ;Save registers push si push ds ;Yes, remove entry from list push es ; by moving the remainder of pop ds ; the list over this entry. mov si,es:[di] ;Point SI to the next list add si,di ; entry. delent_1: cmp word ptr es:[si],-1 ;Check for the end of the list je delent_2 mov cx,es:[si] ;Get size of entry rep movsb ;Copy next entry over current jmp short delent_1 ; entry. delent_2: mov word ptr es:[di],-1 ;Set end of list indicator pop ds ;Get back file buffer pointer pop si pop cx ret delete_aliasent endp ;----------------------------------------------------------------------------- ; LOADALIASFILE loads a file containing a list of alias commands. ; Entry: DS:SI - pointer to the name of the file to open ; exit: CX - size of the file in bytes ; CF - clear if successful ;----------------------------------------------------------------------------- loadaliasfile proc near assume ds:nothing,es:nothing xor bl,bl call scanline ;Find 1st char of filename. mov dx,si ;Copy filename pointer inc bl ;Find end of filename call scanline mov byte ptr [si-1],0 ;Make filename ASCIIZ. dec dx mov ax,3d00h ;Open file (Read only) int 21h jc loadfile_error mov bx,ax ;Copy file handle ; ;Save the name of the file for error messages. ; push si push es mov di,offset filenam_field push cs pop es mov si,dx loadfile_1: lodsb stosb or al,al jne loadfile_1 mov byte ptr es:[di-1],"$" ;Terminate string with $. pop es pop si ; ;Open file and read contents into file buffer. ; mov ah,3fh ;Read alias file xor dx,dx ;Point to base of file buffer. mov cx,cs:[filebuf_size] ;Get size of file buffer. shl cx,1 ;Convert to bytes shl cx,1 shl cx,1 shl cx,1 int 21h mov si,ax mov byte ptr ds:[si],13 ;Append a CR to end of file. mov cx,ax ;Save new file size xor si,si ;Reset file pointer. mov ah,3eh ;Close file. int 21h mov cs:[file_linecount],1 ;Reset line counter. loadfile_exit: clc loadfile_exit1: ret loadfile_error: stc mov dx,offset errmsg6 ;Bad filename specified. jmp short loadfile_exit1 loadaliasfile endp ;----------------------------------------------------------------------------- ; LISTALIAS prints the alias list to screen. ; Entry: ES - segment of the installed code ;----------------------------------------------------------------------------- listalias proc near assume ds:nothing,es:nothing push ds ; ;Print Command stack size and amount of alias buffer space remaining ; mov dx,offset infomsg2 ;Print size of command stack call printmsg mov ax,es:[cmdstack_size] ;Get size of command stack call hex2asc ;Print size mov dx,offset infomsg3 ;Print min cmd length call printmsg xor ax,ax mov al,es:[minlength] ;Get min cmd length to stack call hex2asc ;Print length mov dx,offset infomsg4 ;Print label to buffer size call printmsg lds si,es:[aliaslist_ptr] ;Get pointer to alias list listalias_1: cmp word ptr [si],-1 ;Scan through alias list to je listalias_2 ; find the end of the list. add si,[si] ;Point to next entry jmp short listalias_1 listalias_2: mov ax,es:[aliaslist_size] ;Get offset to end of buffer sub ax,si ;Subtract end of alias list sub ax,2 ;Correct for end pointer call hex2asc ;Print size mov dx,offset infomsg5 ;Indicate if alias translation call printmsg ; is enabled or disabled mov dx,offset infomsg5d ;Disabled message cmp byte ptr es:[chk_alias],0 ;See if alias enabled je listalias_3 mov dx,offset infomsg5e ;Enabled message listalias_3: call printmsg ; ;Scan through alias list to print function key assignments ; xor dx,dx ;Clear alias found flag lds si,es:[aliaslist_ptr] ;Get pointer to alias list listalias_4: cmp word ptr [si],-1 ;Check for end of list jne listalias_5 jmp listalias_11 listalias_5: mov bx,si ;Save pointer to entry. cmp byte ptr [si+5],0 ;See if key assignment je listalias_6 ;If so, skip entry or dh,1 ;Set alias found flag add si,[bx] ;Point to next entry jmp short listalias_4 listalias_6: ; ;Convert scan code into function key label ; test dh,80h ;See if first time though jne listalias_7 push dx mov dx,offset infomsg6 ;If first time print header call printmsgcr pop dx or dh,80h ;Set header printed flag listalias_7: call printtab push dx add si,4 ;Point SI to command string mov al,[si] ;Get key code mov dh,al cmp al,84 ;Check for base code jb listalias_9 sub dh,25 mov di,offset shiftmsg ;Assume shift prefix cmp al,94 ;Check for shift jb listalias_8 sub dh,10 mov di,offset ctlmsg ;Assume control prefix cmp al,104 ;Check for ctl jb listalias_8 mov di,offset altmsg ;Assume alt prefix sub dh,10 listalias_8: push dx ;Print prefix identifier mov dx,di call printmsg pop dx listalias_9: mov dl,"F" ;Set function key mov ah,2 ;Character output int 21h mov al,dh ;Get modified key code sub al,58 ;Convert from scan code to hex xor ah,ah call hex2asc ;Print function key number mov cl,[bx+3] ;Get length of command inc si ;Point SI to command string inc si mov di,bx add di,[bx] cmp byte ptr [di-1],13 ;Check for carrage return jne listalias_10 ; after command. If found, mov dl,'*' ; indicate immediate command mov ah,2 ; by appending an * to the int 21h ; end of the function key. listalias_10: call printtab call printtab call print_string ;Print command to screen mov dx,offset endmsg ;Append carriage return to call printmsg ; advance to next line. SI pop dx ; points to the next entry. jmp listalias_4 ; ;Scan through alias list to print aliases. ; listalias_11: test dh,1 ;See if any aliases found je listalias_exit ;If no aliases, skip remainder mov dx,offset infomsg7 ;Print header call printmsgcr xor cx,cx ;Clear CX lds si,es:[aliaslist_ptr] ;Get pointer to alias list listalias_12: mov bx,si ;Save pointer to entry. cmp byte ptr [si+5],0 ;See if key definition jne listalias_13 ;If so, skip entry add si,[bx] jmp short listalias_14 listalias_13: call printtab add si,4 ;Point SI to alias string mov cl,[bx+2] ;Get length of alias call print_string ;Print alias to screen call printtab call printtab mov cl,[bx+3] ;Get length of command call print_string ;Print command to screen mov dx,offset endmsg ;Append carriage return to call printmsg ; advance to next line. listalias_14: cmp word ptr [si],-1 ;Check for end of list. SI jne listalias_12 ; points to the next entry. listalias_exit: mov dx,offset infomsg8 ;Print pointer to help msg call printmsgcr pop ds clc ret listalias endp ;----------------------------------------------------------------------------- ; PRINTTAB prints a TAB character to the screen. ; Entry: ES - segment of the installed code ;----------------------------------------------------------------------------- printtab proc near assume ds:nothing,es:nothing mov ah,2 ;Character output mov dl,9 ;Print TAB character int 21h ret printtab endp ;----------------------------------------------------------------------------- ; ENABLEALIAS enables alias translation. ; Entry: ES - segment of the installed code ;----------------------------------------------------------------------------- enablealias proc near assume ds:nothing,es:nothing mov byte ptr es:[chk_alias],1 ;Enable alias clc ret enablealias endp ;----------------------------------------------------------------------------- ; DISABLEALIAS disables alias translation. ; Entry: ES - segment of the installed code ;----------------------------------------------------------------------------- disablealias proc near assume ds:nothing,es:nothing mov byte ptr es:[chk_alias],0 ;Disable alias clc ret disablealias endp ;----------------------------------------------------------------------------- ; REMOVE uninstalls the installed program from memory. ;----------------------------------------------------------------------------- remove proc near assume ds:nothing,es:nothing push ds mov dx,offset errmsg1 ;Not installed msg cmp cs:[alrdy_installed],0 ;See if installed je remove_exit ;Not installed, error mov cx,cs:[other_seg] ;Get segment of installed code mov ax,3521h ;Get DOS vector int 21h mov ax,es ;Check to make sure DOS cmp ax,cs:[other_seg] ; vector not modified. jne remove_error lds dx,es:[int2fh] ;Get old interrupt 2F vector cmp dx,-1 ;See if Int used je remove_1 ;No, skip check of Int 2F mov ax,352fh ;Get MUX vector int 21h mov ax,es ;Check to make sure MUX cmp ax,cs:[other_seg] ; vector not modified. jne remove_error mov ax,252fh ;Set interrupt int 21h remove_1: lds dx,es:[int21h] ;Get old interrupt 21 vector mov ax,2521h ;Set interrupt int 21h mov cx,es:[env_segment] mov ah,49h ;Free memory block int 21h mov es,cx ;Free environment block mov ah,49h int 21h mov dx,offset infomsg1 ;Indicate uninstalled. mov byte ptr filenam_field,0 ;Clear filename field remove_exit: stc pop ds remove_exit1: ret remove_error: mov dx,offset errmsg3 ;Can't remove error msg jmp short remove_exit remove endp ;----------------------------------------------------------------------------- ; COMMENT_LINE allows comments in the alias file by skipping to the next ; carriage return. ; Entry: SI - pointer to ASCII string ; CX - file length ;----------------------------------------------------------------------------- comment_line proc near assume ds:nothing,es:nothing comment_loop: push es push ds pop es mov di,si ;Copy file pointer mov al,13 ;Scan for carriage return. repne scasb inc cs:[file_linecount] ;Inc file line counter. mov si,di ;Restore file pointer. pop es clc ret comment_line endp ;----------------------------------------------------------------------------- ; HEX2ASC converts a binary number to ASCII and prints it to the screen. ; Entry: AX - binary number ;----------------------------------------------------------------------------- hex2asc proc near assume ds:nothing,es:nothing push bx mov cx,5 ;Allow max of five digits hex_loop1: xor dx,dx ;Clear high word mov bx,10 ;Load number base div bx ;Divide by base (10) add dl,30h ;Convert to ascii push dx ;Save digit on stack loop hex_loop1 mov cx,5 ;Allow max of five digits mov bl,"0" ;Set leading zero indicator hex_loop2: pop dx ;Get digit off stack or bl,dl ;Don't print leading zeros. cmp bl,"0" ;The first non zero will je hex_1 ; change bl to non-zero. mov ah,2 ;DOS character output int 21h hex_1: loop hex_loop2 hex_exit: pop bx ret hex2asc endp ;----------------------------------------------------------------------------- ; ASC2BIN - converts an ASCII number of the command line to hex. ; Entry: DS:SI - pointer to ASCII number ;----------------------------------------------------------------------------- asc2bin proc near push bx xor bl,bl call scanline ;Find next character. mov di,offset errmsg5 ;Bad number message jc asc_error ;If no number found, error mov bl,al ;Copy first digit. xor ax,ax ;Clear out sum xor bh,bh ;Clear high byte for word adds asc_loop: cmp bl," " ;If space, assume end of jbe asc_exit ; number. cmp bl,"]" ;Exit if closing bracket je asc_exit ; encountered sub bl,"0" ;Check for valid number then jb asc_error ; convert to binary. cmp bl,9 ja asc_error mov dx,10 ;DX holds base multiplier mul dx ;Shift over current number jc asc_overflow ;If overflow, indicate error add ax,bx ;Add new digit to sum. jcxz asc_exit ;If end of file, exit. mov bl,ds:[si] ;Get next ASCII character inc si ;Point to next character dec cx ;Dec file size counter jmp short asc_loop ;Go back for more asc_exit: clc ;Clear error flag. asc_exit1: pop bx ret asc_overflow: mov di,offset errmsg12 ;Number too large message. asc_error: mov dx,di ;Copy message pointer. stc ;Set error flag. jmp short asc_exit1 asc2bin endp ;----------------------------------------------------------------------------- ; SCANLINE performs the same function as SCAN4CHAR but keeps track of the ; carriage returns. ; Entry: SI - pointer to ASCII string ; BL - 0 = find next char, 1 = find next space ; CX - file length ; Exit: AL - first nonspace character ; CF - set if carriage return found ;----------------------------------------------------------------------------- scanline proc near call scan4char ;Find the next char. jnc scanline_exit inc cs:[file_linecount] ;Point to next line. stc scanline_exit: ret scanline endp end_of_code = $ code ends end main ------------