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Assembly Source File | 1987-01-17 | 24.4 KB | 481 lines

;CHECK.COM for the IBM Personal Computer - 1986 by Jeff Prosise .8087 ;recognize 8087/80287 instructions code segment para public 'code' assume cs:code,ds:code org 100h begin: jmp check ;skip data area ; notice db ' Copyright 1986 Ziff-Davis Publishing Co.' notice_2 db ' Programmed by Jeff Prosise' keywords db 'MEMORY',0,'FILESIZE',0,'VIDEOCARD',0 db 'MODEL',0,'8087',0,'80287',0 db 'FILEFOUND',0,'FILETEXT',0,'DISKSPACE',0 db 'VIDEOMODE',0,'TIME',0,'DAY',0,'MONTH',0 db 'VERSION',0,'KEYBOARD',0,'KEYPRESS',0 ; jump_table dw offset keypress ;vector dispatch table dw offset keyboard dw offset version dw offset month dw offset day dw offset time dw offset videomode dw offset diskspace dw offset filetext dw offset filefound dw offset mathproc dw offset mathproc dw offset model dw offset videocard dw offset filesize dw offset memory ; ibm db 'IBM' ;EGA signature parameter_count db ? ;number of command line parameters string_length dw 0 ;length of text string in bytes file_handle dw ? ;storage area for DOS file handle command_index dw ? ;storage for parsing index keyword_buffer dw offset endprog ;pointer to keyword buffer param1_buffer dw offset endprog+16 ;pointer to parameter buffer text_string dw offset endprog+144 ;pointer to text string buffer dta dw offset endprog+272 ;pointer to Disk Transfer Area control_bytes label byte ;byte accessor to control word control_8087 dw 0 ;8087/80287 control word ; errmsg1 db 13,10,'Invalid Keyword',13,10,'$' errmsg2 db 13,10,'Missing Parameter',13,10,'$' errmsg3 db 13,10,'Invalid Drive Specifier',13,10,'$' errmsg4 db 13,10,'Invalid String Specifier',13,10,'$' errmsg5 db 13,10,'File Not Found',13,10,'$' ; check proc near cld ;clear DF for string instructions call parse_line ;parse command line for entries cmp parameter_count,0 ;any parameters entered? jne check1 ;yes, then continue lea dx,errmsg2 ;no - load error msg address jmp error1 ;abort on error check1: lea si,keywords ;point SI to keyword list mov cx,16 ;number of reserved keywords check2: mov di,keyword_buffer ;point DI to keyword just entered check3: lodsb ;get character or al,al ;is it a zero byte? je match_found ;yes, then keywords match scasb ;compare it to byte in buffer je check3 ;loop back on match dec cx ;no match - decrement counter jcxz error_exit ;list scanned unsuccessfully check4: lodsb ;index SI to next word in list or al,al ;is this byte a zero? jne check4 ;no, try again jmp check2 ;SI set - try another keyword ; ;Execution comes here when the keyword entered on the command line matches one ;of the recognized keywords. The count in CX is translated into a pointer to ;the address of the routine to be vectored to. ; match_found: mov bx,cx ;get keyword number in BX dec bx ;decrement it by 1 shl bx,1 ;multiply by two to form index jmp word ptr cs:[offset jump_table+bx] ;goto handler ; ;Execution comes here when an error is encountered. ; error_exit: lea dx,errmsg1 ;load address of error message error1: push ax ;save error return code in AL mov ah,9 ;DOS function - Print String int 21h ;print error message pop ax ;retrieve return code ; ;EXIT is the common point of exit for all routines in the program. A return ;code is set that can be read as the ERRORLEVEL parameter by batch processes. ; exit: mov ah,4Ch ;DOS function - Exit Program int 21h ;exit with return code check endp ; ;Model routine returns the machine ID byte of the computer being used. ; model proc near mov ax,0F000h ;set ES to ROM segment mov es,ax mov di,0FFFEh ;load DI with offset of ID byte mov al,es:[di] ;get machine ID byte into AL jmp exit ;exit model endp ; ;VideoMode routine returns the current video mode (0-16). ; videomode proc near mov ah,15 ;INT 10h function - Get Video Data int 10h ;get video mode in AL jmp exit ;exit videomode endp ; ;VideoCard routine returns a value indicating what kind of video adapter is ;being used in the system (0=MDA, 1=CGA, 2=EGA). ; videocard proc near mov dl,2 ;initialize DL mov bx,0C000h ;set ES to EGA BIOS segment mov es,bx mov di,1Eh ;set DI to IBM signature address lea si,ibm ;set SI to 'IBM' text mov cx,3 ;three bytes to check repe cmpsb ;compare the three bytes je card1 ;this is an EGA - jump to exit dec dl ;adjust DL for MDA or CGA mov ah,15 ;get current video mode int 10h cmp al,7 ;is it mode 7? jne card1 ;no, then this is a CGA dec dl ;zero DL for MDA card1: mov al,dl ;set AL for exit jmp exit ;and exit videocard endp ; ;Memory routine returns the number of 16K RAM modules present in the system. ; memory proc near int 12h ;get memory size from BIOS mov cl,4 ;set CL to 4 for shift shr ax,cl ;shift 4 times to divide by 16 jmp exit memory endp ; ;FileFound returns 0 if the indicated file is found, 1 if it's not. ; filefound proc near cmp parameter_count,1 ;more than 1 parameter entered? ja filefnd1 ;yes, then continue lea dx,errmsg2 ;no, then get error msg address mov al,1 ;set AL to 1 to indicate failure jmp error1 ;and exit filefnd1: mov dx,param1_buffer ;point DX to filename mov ah,3Dh ;use DOS Open File function xor al,al ;set AL to 0 for read-only access int 21h ;attempt to open the file jnc filefnd2 ;open process succeeded mov al,1 ;open failed - set AL to 1 jmp exit filefnd2: mov bx,ax ;get file handle in BX mov ah,3Eh ;use DOS Close File function int 21h ;close file just opened xor al,al ;zero AL for exit jmp exit filefound endp ; ;KeyBoard returns 1 if a key has been pressed, 0 if one has not. ; keyboard proc near mov ah,1 ;use BIOS to check buffer int 16h ;get status of keyboard buffer je kb1 ;empty if ZF set mov al,1 ;not empty - set AL to 1 jmp exit kb1: xor al,al ;buffer empty - zero AL jmp exit keyboard endp ; ;KeyPress returns waits for a keypress (if one isn't already buffered) and ;returns its ASCII code. ; keypress proc near mov ah,0 ;use BIOS function to read keypress int 16h ;get keypress - ASCII code in AL jmp exit keypress endp ; ;Version returns the major number of the version of DOS in use. ; version proc near mov ah,30h ;use DOS Get Version function int 21h ;get version number jmp exit version endp ; ;DiskSpace returns the number of whole 16K blocks of free disk space from the ;indicated or default drive. AL is 0 on exit if an error is encountered. A ;return value of 255 means there are that many blocks or more free. ; diskspace proc near xor dl,dl ;set DL to 0 for default drive cmp parameter_count,1 ;only one parameter entered? je dspace1 ;yes, then use default drive mov si,param1_buffer ;set SI to parameter text lodsb ;get first character in parameter sub al,64 ;convert to DOS drive designator mov dl,al ;shift designator to DL lodsb ;get following character cmp al,':' ;is it a colon? je dspace1 ;yes, then continue lea dx,errmsg3 ;no, then load error msg address xor al,al ;set AL for failure jmp error1 ;exit on error dspace1: mov ah,36h ;use DOS Get Free Space function int 21h ;get disk information cmp ax,0FFFFh ;drive designator error? jne dspace2 ;no, then continue lea dx,errmsg3 ;abort on drive error xor al,al jmp error1 dspace2: mul cx ;multiply to get bytes per cluster mul bx ;multiply again to get free bytes mov cx,14 ;set shift counter dspace3: shr dx,1 ;shift AX:DX right 14 bits rcr ax,1 loop dspace3 ;loop until done or ah,ah ;is the MSB zero? je dspace4 ;yes, then continue mov al,255 ;no, then set AL to 255 dspace4: jmp exit diskspace endp ; ;Time returns the current hour of the day (0-23). ; time proc near mov ah,44 ;get current time from DOS int 21h mov al,ch ;place hour in AL jmp exit time endp ; ;Day returns the current day of the month (1-31). ; day proc near mov ah,42 ;get current date from DOS int 21h mov al,dl ;put day in AL jmp exit day endp ; ;Month returns the current month number (1-12). ; month proc near mov ah,42 ;get date from DOS int 21h mov al,dh ;put month in AL jmp exit month endp ; ;FileText returns 0 if the specified string is found within the indicated ;file. A 1 is returned if the string is not contained within the file, if ;the file is not found, or if a syntax error is detected on the command line. ; filetext proc near cmp parameter_count,2 ;at least two parameters entered? je text1 ;yes, then continue lea dx,errmsg2 ;no, then abort mov al,1 jmp error1 text1: mov si,command_index ;point SI to end of second param mov di,text_string ;point DI to string buffer text2: lodsb ;get next character cmp al,32 ;is it a space character? je text2 ;yes, then go back for another cmp al,39 ;is it a quote mark? je text4 ;yes, then branch and continue cmp al,13 ;end-of-line marker? jne text3 ;no, it's an invalid character lea dx,errmsg2 ;abort - string missing mov al,1 jmp error1 text3: lea dx,errmsg4 ;abort - syntax error in string mov al,1 jmp error1 text4: lodsb ;get character in string cmp al,13 ;end-of-line marker? je text3 ;yes, then abort cmp al,39 ;quote mark? je text5 ;yes, then end of string reached stosb ;copy character to string buffer inc string_length ;increment length count jmp text4 ;go back for another character text5: cmp string_length,0 ;any characters in string? jne text6 ;yes, then continue lea dx,errmsg4 ;no, then abort mov al,1 jmp error1 text6: mov dx,param1_buffer ;point DX to filename mov ah,3Dh ;open the file xor al,al int 21h jnc text7 ;continue if open succeeded lea dx,errmsg5 ;abort if it failed mov al,1 jmp error1 text7: mov file_handle,ax ;save file handle text8: mov dx,dta ;point DX to Data Transfer Area mov cx,0C000h ;specify C000h bytes to be read mov bx,file_handle ;get DOS file handle mov ah,3Fh ;DOS function - Read Block int 21h ;read block from file on disk cmp ax,string_length ;enough bytes read in to compare? jb not_found ;no, then terminate mov bx,ax ;save actual bytes read in BX mov cx,ax ;prepare CX for comparison loop sub cx,string_length inc cx mov di,dta ;point DI to block just read text9: push cx ;save loop counter push di ;save start index mov cx,string_length ;prepare to compare string mov si,text_string ;point SI to string text repe cmpsb ;compare while equal pop di ;restore saved registers pop cx je text_found ;match found if ZF set inc di ;increment starting index loop text9 ;loop until entire block examined cmp bx,0C000h ;was end-of-file reached? jne not_found ;yes, then exit - string not found mov ah,42h ;DOS function - Move File Pointer mov al,1 ;method code - current pos + offset mov cx,0FFFFh ;form negative integer in DX:CX mov dx,string_length ;get string length in low word not dx ;form complement add dx,1 ;form two's complement adc cx,0 ;carry into high word (CX) mov bx,file_handle ;get file handle int 21h ;move file pointer back jmp text8 ;read another block from disk text_found: xor al,al ;text found - zero AL jmp close_file not_found: mov al,1 ;text not found - set AL to 1 close_file: push ax ;save return code in AL mov ah,3Eh ;close file before exiting mov bx,file_handle int 21h pop ax ;restore AL jmp exit filetext endp ; ;FileSize returns the length in kilobytes of the specified file. A value of ;255 means the file is 255K or greater in length. 0 is returned if the file ;cannot be found. ; filesize proc near cmp parameter_count,1 ;more than 1 parameter entered? ja size1 ;yes, then continue lea dx,errmsg2 ;no filename - abort xor al,al jmp error1 size1: mov dx,param1_buffer ;point DX to ASCIIZ filename mov ah,3Dh ;use DOS Open File function xor al,al ;open for reading only int 21h ;open the file jnc size2 ;continue if open succeeded lea dx,errmsg5 ;abort if it did not xor al,al jmp error1 size2: push ax ;save file handle on stack mov bx,ax ;get file handle in BX mov ah,42h ;use DOS to move file pointer mov al,2 ;method code - EOF + offset xor cx,cx ;specify 0 offset in DX:CX xor dx,dx int 21h ;move file pointer to EOF pop bx ;get file handle push ax ;save EOF address push dx mov ah,3Eh ;close file int 21h pop dx ;retrieve address pop ax mov cl,10 ;prepare CL for shift size3: shr dx,1 ;shift AX:DX right 10 bits rcr ax,1 loop size3 or dx,dx ;DX = 0 ? jne max_length ;no, filesize > 255K or ah,ah ;AH = 0 ? jne max_length ;no, filesize > 255K jmp exit ;length in AL max_length: mov al,255 ;set AL to 255 for exit jmp exit filesize endp ; ;Mathproc returns a 1 if neither an 8087 nor an 80287 math coprocessor is ;detected in the system or a 0 if one of them is. ; mathproc proc near fninit ;initialize (set control word) fnstcw control_8087 ;write control word to memory cmp control_bytes[1],3 ;control word correctly written? je found_8087 ;yes, then 8087/80287 is there mov al,1 ;no coprocessor - set AL to 1 jmp exit found_8087: xor al,al ;zero AL jmp exit mathproc endp ; ;------------------------------------------------------------------------------ ;PARSE_LINE parses the command line for the first two parameters entered and ;writes them into their respective storage buffers. ;------------------------------------------------------------------------------ parse_line proc near mov parameter_count,0 ;zero count of entries mov si,81h ;set SI to start of text call next_parameter ;index to next parameter jc parse_exit ;exit if there's not one mov di,keyword_buffer ;set DI for output call get_parameter ;parse parameter to buffer inc parameter_count ;increment count call next_parameter ;index to next parameter jc parse_exit ;exit if there's not one mov di,param1_buffer ;set DI for output call get_parameter ;get next parameter inc parameter_count ;increase count parse_exit: mov command_index,si ;save SI for additional parsing ret ;and exit parse_line endp ; ;------------------------------------------------------------------------------ ;NEXT_PARAMETER indexes SI to the next non-space character. ;Entry: DS:SI - current character | Exit: CF clear - character found ; | CF set - end-of-line reached ;------------------------------------------------------------------------------ next_parameter proc near cmp byte ptr [si],13 ;end-of-line reached? je end_of_line ;yes, then jump cmp byte ptr [si],32 ;space character (delimiter)? jne no_space ;no, then character found inc si ;advance pointer jmp next_parameter ;check another character no_space: clc ;clear CF for exit ret end_of_line: stc ;set CF to indicate EOL ret next_parameter endp ; ;------------------------------------------------------------------------------ ;GET_PARAMETER transfers the command line parameter indexed by SI into the ;designated buffer area, capitalizing lowercase characters in the process and ;terminating the string with a zero for ASCIIZ representation. ;Entry: DS:SI - parameter address ; ES:DI - buffer address ;------------------------------------------------------------------------------ get_parameter proc near cmp byte ptr [si],13 ;end-of-line reached? je end_get ;yes, then we're done cmp byte ptr [si],32 ;space delimiter encountered? je end_get ;yes, then we're done lodsb ;get the character cmp al,97 ;is it a lowercase character? jb getparam1 cmp al,122 ja getparam1 and al,0DFh ;yes, then capitalize it getparam1: stosb ;buffer the character jmp get_parameter ;loop back for more end_get: xor al,al ;zero AL stosb ;end string with 0 delimiter ret get_parameter endp ; endprog label byte ;start of buffer area ; code ends end begin