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Assembly Source File | 1984-05-01 | 10.8 KB | 284 lines

;====================================================== ; COM2DATA release 2.0 ; (c) 1984 by David Whitman ; ; High speed DOS 2.0 filter version ; of file conversion utility. ; ; Reads a COM file from STDIN and ; writes BASIC data statements to STDOUT ; ; Syntax: COM2DATA [<filename] [>filename] [linenumber] ; ; The starting line number defaults to 1000 unless a number ; is given on the command line. ; ; Requires DOS 2.0, will abort under earlier versions. ; ; This source file is in CHASM assembler syntax. ;====================================================== @dosver equ 30H ;get dos version # @prnchr equ 02H ;print character @prnstr equ 09H ;print string @read equ 3FH ;read device @write equ 40H ;write device beep equ 07H ;bell character lf equ 0AH ;line feed character cr equ 0DH ;carrage return character comma equ 2CH ;comma character param_count equ [80H] ;number of chars in param_area param_area equ [81H] ;command line parameter text stdin equ 0000H ;standard input device stdout equ 0001H ;standard output device stderror equ 0002H ;standard error output device buf_length equ 512 ;input buffer size com2data proc near call init ;check dos, print title call get_linenum ;get starting line number call doit ;run conversion call cleanup ;final processing int 20H ;return to dos endp init proc near ;initialization routine mov ah, @dosver ;what dos are we under? int 21H cmp al,2 ;dos 2.0 or over? jae a1 ;yes, skip mov ah, @prnstr ;no, bitch mov dx, offset(baddos) int 21H pop ax ;reset stack int 20 ;and exit a1 mov ah, @write ;send title message mov bx, stderror ;to stderror mov cx, length(title_msg) mov dx, offset(title_msg_txt) int 21H ret baddos db beep cr lf db 'This program requires DOS 2.0!' cr lf db cr lf '$' title_msg count title_msg_txt db cr lf db 'COM2DATA version 2.0' cr lf db 'Copyright (c) 1984 by D. Whitman' cr lf db cr lf endc endp get_linenum proc near ;parse command line for ;starting line number xor ch,ch ;cx <== # of param chars mov cl, param_count ; " cmp cl, 0 ;any parameters? je b1 ;no, exit with default mov di, offset(param_area) mov al, ' ' ;search for first non-blank rep scasb jcxz b1 ;nothing? exit with default dec di ;back up to character found inc cx ; " xor ax,ax ;will hold building linenum jmps enter_convert ;convert string to binary convert mov bx, 10 ;multiply running total by 10 mul ax,bx jo bad_num ;overflow? error exit enter_convert xor bx,bx ;clear out top half mov bl, [di] ;get a digit into al inc di ;bump pointer cmp bl, '0' ;must be between 0 jb bad_num cmp bl, '9' ;and 9 ja bad_num sub bl, '0' ;convert to binary add ax, bx ;add to running total jo bad_num ;overflow? error exit loop convert mov linenum, ax ;store converted number ret ;normal return bad_num mov ah, @write ;print error message mov bx, 2 ;on stderror mov cx, length(num_msg) mov dx, offset(num_msg_txt) int 21H ;and use default b1 ret ;normal return linenum dw 1000 ;line number defaults to 1000 num_msg count num_msg_txt db beep cr lf db 'Invalid starting line number - Defaulting to 1000' cr lf db cr lf endc endp doit proc near ;convert infile to data do1 mov ah, @read ;read mov bx, stdin ;from stdin mov cx, buf_length ;one buffer's worth mov dx, offset(in_buf) int 21H test ax, ax ;test for EOF jz done ;no bytes? done mov cx, ax ;cx <== # of bytes read mov si, offset(in_buf) do2 lodsb ; call output ;convert and send to stdout loop do2 ;loop for # of bytes read jmps do1 ;then refill buffer done ret endp output proc near ;convert byte in al to hex string ;and send to stdout cmpw cur_pos, offset(eol) ;is the line full? jb o1 ;no, skip call newline ;yes, dump buffer o1 call send_byte ;print hex value of byte addw cur_pos, 8 ;bump line positions used ret ;and exit cur_pos dw offset(first_hex) ;current position in line endp newline proc near ;starts a new data line push ax ;save state push bx ; " push cx ; " push dx ; " push di ; " mov al, ' ' ;blank out old number mov di, offset(out_buf) mov cx, 5 rep stosb mov ax, linenum ;print line number ;the following code fragment was written ;by Bob Smith and published in PC Age ;Volume 3.1 (Jan. '84) p. 116 mov bx, 10 ;set up divisor xor cx, cx ;clear counter nxt_in xor dx, dx ;clear for division div bx ;dl <== AX mod 10 or dl, '0' ;convert to ascii digit push dx ;save digit inc cx ;bump counter and ax, ax ;are we done? jnz nxt_in ;nope, keep going ;stack now has digits of number ;end of Bob Smith's code mov di, offset(out_buf) ;peel digits off stack nxt_out pop ax ;into number field stosb loop nxt_out mov ah, @prnstr ;now print line mov dx, offset(out_buf) int 21H movw cur_pos, offset(first_hex) ;reset pointer addw linenum, 10 ;bump line number pop di ;restore state pop dx pop cx pop bx pop ax ret ;and exit endp send_byte proc near ;converts byte in AL to hex string ;and stuffs it into output buffer push bx push dx push ax mov bx, offset(table) ;point to xlat table and al, 0F0H ;mask off low nybble shr al shr al shr al shr al xlat ;translate to hex string mov bp, cur_pos ;and stuff it into buffer mov [bp], al pop ax ;recover character and al, 0FH ;mask off high nybble xlat ;translate low nybble to hex mov 1[bp], al ;and stuff it into buffer pop dx pop bx ret ;and return table db '0123456789ABCDEF' endp cleanup proc near ;send out any partial line cmpw cur_pos, offset(first_hex) ;any unprinted chars? je cexit ;no, exit mov ah, @write mov bx, stdout mov cx, cur_pos sub cx, offset(out_buf) sub cx, 5 mov dx, offset(out_buf) int 21H mov ah, @prnstr mov dx, offset(eol) int 21H cexit ret endp out_buf ds 5 ;5 digit line number db ' DATA' db ' &H' ;8 hex bytes per line first_hex db '00' comma ;first hex field db ' &H00' comma db ' &H00' comma db ' &H00' comma db ' &H00' comma db ' &H00' comma db ' &H00' comma db ' &H00' eol db cr lf '$' ;end of output line in_buf