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Assembly Source File | 1988-02-16 | 21.5 KB | 498 lines

;---------------------------------------------------------------------- ; RUN.ASM ; Format: RUN [/C][/S][d:][directory] filename [arguments] ; /C = Change to the directory and run ; /S = Stay in current directory and run ; Default is /S ;---------------------------------------------------------------------- CODE SEGMENT ;********************************; ASSUME CS:CODE,DS:CODE ;* *; ORG 100H ;* Requires MASM 2.0 or later *; ;* Remember to EXE2BIN *; START: JMP BEGINNING ;* *; ;********************************; ; DATA AREA ; --------- COPYRIGHT DB "RUN 1.0 (c) 1987 Ziff Communications Co.",13,10 DB "PC Magazine ",254," Michael J. Mefford",13,10,"$",26 CURRENT_DISK DB ? WORKING_DISK DB 0FFH FILE_START DW ? FILENAME_END DW ? ARGUMENTS DW ? PATH_END DW 0 CHANGE_FLAG DB 0 BAT_FLAG DB 0 SYNTAX DB 13,10,"Syntax: RUN [/C][/S][d:][directory] filename [arguments]" DB 13,10,"/C = Change to the directory and run" DB 13,10,"/S = Stay in current directory and run" DB 13,10,"Default is /S" CR_LF DB 13,10,"$" FAIL DB 13,10,"Can't find $" SEARCHING DB 13,10,"Searching for $" DELIMITERS DB 9,13,32,"/<>." EXE DB "EXE",0 COM DB "COM",0 BAT DB "BAT",0 ROOT DB "\",0 STAR_DOT_STAR DB "*.*",0 PARENT DB "..",0 COPY DB " /C " COMSPEC DB "COMSPEC=" STACK_SEG DW ? STACK_PTR DW ? PARAMETER_BLOCK LABEL WORD ENVIRONMENT DW 0 COM_LINE_PTR DW PARAMETER,? FCB_1ST DW FCB_5CH, ? FCB_2ND DW FCB_6CH, ? ;----------------------------------------------------------------------------; ; Some housekeeping first. Since we will be changing the default drive ; ; and directory to the requested drive and directory, we need to save the ; ; current defaults, so they can be restored. Change the default DTA. ; ; Move the stack and deallocate memory so we have room to spawn the program. ; ;----------------------------------------------------------------------------; ; CODE AREA ; --------- BEGINNING: MOV AH,9 MOV DX,OFFSET COPYRIGHT INT 21H CLD ;String moves forward. CALL GET_DRIVE ;Get current drive. MOV CURRENT_DISK,AL ;Save. MOV SI,OFFSET CURRENT_DIR ;Get current directory. CALL GET_DIR MOV DX,OFFSET DTA ;Move the disk transfer address MOV AH,1AH ; to the end of code to protect INT 21H ; command line parameters at 80h. MOV SP,OFFSET CODE_END ;Move the stack down to the MOV BX,SP ; end of code segment. ADD BX,15 ;Round up paragraph size. MOV CL,4 SHR BX,CL MOV AH,4AH ;Deallocate rest of memory. INT 21H ;--------------------------------------------------; ; Parse the command line parameters. Start by ; ; scanning off spaces and RUN's switch characters. ; ;--------------------------------------------------; MOV SI,80H ;Point to command line parameters. LODSB CMP AL,0 ;Are there any? JZ BAD_SYNTAX ;If no, exit. NEXT_LEADING: LODSB ;Get a byte. CMP AL,"/" ;Is it a switch character? JNZ CK_CR ;If no, check if end. LODSB ;Else, get switch character. CMP AL,13 ;Make sure not end. JZ BAD_SYNTAX AND AL,5FH ;Capitalize. CMP AL,"C" ;Is it "C"? JNZ CK_NOCHANGE MOV CHANGE_FLAG,1 ;If yes, indicate to change dir. CK_NOCHANGE: CMP AL,"S" ;Else, is it "S"? JNZ NEXT_LEADING ;If no, next leading character. MOV CHANGE_FLAG,0 ;Else, indicate not to change dir. JMP SHORT NEXT_LEADING CK_CR: CMP AL,13 ;Is it carriage return? JNZ CK_LEADING ;If yes, bad syntax. BAD_SYNTAX: JMP SYNTAX_EXIT CK_LEADING: CMP AL,32 ;Is it a space or tab? JBE NEXT_LEADING ;If yes, get next character. DEC SI ;Else, adjust pointer back one. PUSH SI ;Save as possible path request. MOV FILE_START,SI ;Save as possible start of filename ;----------------------------------------------------; ; We now have the start of the run file. Next scan ; ; to the end of filename looking for a path request. ; ;----------------------------------------------------; NEXT_PATH: LODSB ;Get a byte. CMP AL,":" ;Drive request? JNZ CK_PATH ;If no, check if directory. MOV DL,[SI-2] ;Else, retrieve drive. AND DL,5FH ;Capitalize. SUB DL,"A" ;Convert to DOS format. CALL CHANGE_DRIVE ;Change drive. MOV FILE_START,SI ;Save as possible start of filename JMP SHORT NEXT_PATH CK_PATH: CMP AL,"\" ;Is it a path delimiter? JNZ CK_DELIMITER ;If no, see if end of filename. MOV PATH_END,SI ;Else, save as path end. MOV FILE_START,SI ;Save as possible start of filename CK_DELIMITER: MOV DI,OFFSET DELIMITERS ;Check for tab, carriage return, MOV CX,6 ; space, switch, or redirection REPNZ SCASB ; characters as filename end. JNZ NEXT_PATH ;Continue until found. DEC SI ;Else, adjust pointer back one. MOV ARGUMENTS,SI ;Save as start of arguments. ;--------------------------------------------------; ; Parse the arguments for two file control blocks. ; ;--------------------------------------------------; MOV DI,OFFSET FCB_5CH ;Point to first FCB storage. MOV AX,2901H ;Parse and scan off leading INT 21H ; separators. MOV DI,OFFSET FCB_6CH ;Same for second FCB. MOV AX,2901H INT 21H ;----------------------------------------------------; ; Store working path so can be restored on exit. ; ; Store run filename stripping extension in process. ; ;----------------------------------------------------; CALL GET_DRIVE ;Store working drive. MOV WORKING_DISK,AL MOV SI,OFFSET WORKING_DIR ;Store working directory. CALL GET_DIR MOV SI,FILE_START ;Store the run filename. MOV DI,OFFSET FILENAME NEXT_FILENAME: LODSB ;Get a byte. PUSH DI MOV DI,OFFSET DELIMITERS ;Are we at the end of filename MOV CX,7 ; or encountered dot? REPNZ SCASB POP DI JZ STORE_DOT ;If yes, done here. STOSB JMP SHORT NEXT_FILENAME STORE_DOT: MOV AL,"." STOSB MOV FILENAME_END,DI ;Store end of filename. ;---------------------------------------------------------; ; If a path was found, change directory and search for ; ; run file. Else, do a diskwide search for the run file. ; ;---------------------------------------------------------; POP DX ;Retrieve filespec start. MOV SI,PATH_END ;Did we find a path? CMP SI,0 JZ GLOBAL ;If no, do global search. CMP BYTE PTR [SI-2],":" ;Else, check if special JZ CHANGE_IT ; case of root directory. CMP BYTE PTR [SI-2],32 JBE CHANGE_IT ;If yes, change directory. DEC SI ;If no, adjust pointer. CHANGE_IT: PUSH [SI] ;Save path end. MOV BYTE PTR [SI],0 ;Convert to ASCIIZ for DOS. CALL CHANGE_DIR ;Change directory. POP [SI] ;Restore path end. CALL CK_EXECUTABLE ;Search current directory JNC RUN_IT ; for filename; run it if found. JMP SHORT ERROR_EXIT ;Else, exit with message. GLOBAL: CALL GLOBAL_SEARCH ;If no directory request, do a JC ERROR_EXIT ; diskwide search for filename. RUN_IT: CALL EXEC ;If found, execute it. JMP SHORT EXIT ;-----------------------------------------------------------------------; ; This is the exit routine. Restore the defaults the way we found them. ; ;-----------------------------------------------------------------------; ERROR_EXIT: MOV DX,OFFSET FAIL ;Display "Can't find ". CALL PRINT_STRING CALL PRINT_NAME ;Display filename. SYNTAX_EXIT: MOV DX,OFFSET SYNTAX ;Display RUN syntax. CALL PRINT_STRING MOV AL,1 ;Error code of one. JMP SHORT TERMINATE EXIT: XOR AL,AL ;Error code of zero. TERMINATE: PUSH AX ;Save error code. CALL RESTORE_PATH ;Restore defaults. POP AX ;Retrieve error code. MOV AH,4CH ;Exit. INT 21H ;***************; ;* SUBROUTINES *; ;***************; ;-----------------------------------------------------------------; ; This subroutine adds the extension COM, EXE and BAT ; ; (in that order) to the filename and checks to see if it exists. ; ;-----------------------------------------------------------------; CK_EXECUTABLE: MOV DX,OFFSET FILENAME ;Point to filename. MOV BX,FILENAME_END ;Point to filename end. MOV SI,OFFSET COM ;Check for .COM CALL FIND_MATCH JNC CK_END MOV SI,OFFSET EXE ;Check for .EXE CALL FIND_MATCH JNC CK_END MOV SI,OFFSET BAT ;Check for .BAT CALL FIND_MATCH JC CK_END MOV BAT_FLAG,1 ;If batch file, indicate so. CK_END: RET ;---------------------------; FIND_MATCH: MOV DI,BX ;Add extension to filename. MOVSW MOVSW MOV CX,7 CALL FIND_FIRST ;See if it exists. RET ;-----------------------------------------------------------------; ; This subroutine executes the file. If it's a batch file, load ; ; secondary copy of COMMAND.COM. Else, let 4Bh execute the file. ; ;-----------------------------------------------------------------; EXEC: PUSH DS ;Save segment registers. PUSH ES CLI MOV STACK_SEG,SS ;Save stack segment and pointer. MOV STACK_PTR,SP STI MOV COM_LINE_PTR + 2,DS ;Point to command line. MOV FCB_1ST + 2,DS ;Point to file control blocks. MOV FCB_2ND + 2,DS CMP BAT_FLAG,1 ;Is it a batch file? JNZ EXECUTE ;If no, just execute file. MOV SI,OFFSET COPY ;Else, let COMMAND.COM/C run it. MOV DI,OFFSET PARAMETER + 1 ;Construct parameter. MOVSW MOVSW CALL MAKE_FILESPEC ;Add filespec. DEC DI CALL ADD_PARAMETER ;Add arguments. MOV AX,DS:[2CH] ;Retrieve environment segment. MOV DS,AX XOR AX,AX FIND_COMSPEC: MOV SI,AX ;Search for "COMSPEC=". INC AX MOV DI,OFFSET COMSPEC MOV CX,4 REPZ CMPSW JNZ FIND_COMSPEC MOV DX,SI ;What follows is COMMAND.COM path. JMP SHORT EXEC_FILE ;Ready to execute. EXECUTE: MOV DI,OFFSET FILESPEC ;Construct filespec. CALL MAKE_FILESPEC MOV DI,OFFSET PARAMETER + 1 ;Construct arguments. CALL ADD_PARAMETER MOV DX,OFFSET FILESPEC EXEC_FILE: MOV BX,OFFSET PARAMETER_BLOCK ;Point to parameter block. MOV AX,4B00H ;Execute. INT 21H CLI MOV SP,CS:STACK_PTR ;Restore stack segment and pointer. MOV SS,CS:STACK_SEG STI POP ES ;Restore segment registers. POP DS RET ;---------------------------; MAKE_FILESPEC: CMP CHANGE_FLAG,1 ;Are we to change directory? JZ ADD_FILENAME ;If yes, execute filename. MOV AL,WORKING_DISK ;Else, add working drive. ADD AL,"A" STOSB MOV AL,":" STOSB MOV SI,DI ;Add working directory. CALL GET_DIR CALL RESTORE_PATH ;Restore default path. MOV DI,SI CMP BYTE PTR [DI],0 ;If root, ready for filename. JZ ADD_FILENAME FIND_END: INC DI ;Else, find end of path. CMP BYTE PTR [DI],0 JNZ FIND_END MOV AL,"\" ;Tack on "\" path delimiter. STOSB ADD_FILENAME: MOV SI,OFFSET FILENAME ;Add on filename. NEXT_NAME: LODSB STOSB CMP AL,0 JNZ NEXT_NAME RET ;---------------------------; ADD_PARAMETER: MOV SI,ARGUMENTS ;Add on arguments. GET_PARAMETER: LODSB STOSB CMP AL,13 JNZ GET_PARAMETER XOR CL,CL ;Zero in counter. MOV SI,OFFSET PARAMETER + 1 CNT_PARAMETER: LODSB CMP AL,13 JZ END_PARAMETER INC CL ;Count parameter length. JMP SHORT CNT_PARAMETER END_PARAMETER: MOV PARAMETER,CL ;Store as first byte of parameter. RET ;---------------------------------------------; ; This subroutine restores the default paths. ; ;---------------------------------------------; RESTORE_PATH: CMP WORKING_DISK,0FFH ;Did we get defaults? JZ END_RESTORE ;If no, done here. MOV DX,OFFSET WORKING_DIR CALL CHANGE_DIR MOV DL,CURRENT_DISK CALL CHANGE_DRIVE MOV DX,OFFSET CURRENT_DIR CALL CHANGE_DIR END_RESTORE: RET ;----------------------------------------; ; These are the DOS support subroutines. ; ;----------------------------------------; PRINT_NAME: MOV SI,OFFSET FILENAME ;Print filename NEXT_PRINT: LODSB CMP AL,"." JZ END_NAME MOV DL,AL MOV AH,2 ; via DOS Display Output. INT 21H JMP SHORT NEXT_PRINT END_NAME: MOV DX,OFFSET CR_LF ;Print carriage return linefeed. CALL PRINT_STRING RET GET_DRIVE: MOV AH,19H JMP SHORT DOS_CALL CHANGE_DRIVE: MOV AH,0EH JMP SHORT DOS_CALL FIND_FIRST: MOV AH,4EH JMP SHORT DOS_CALL FIND_NEXT: MOV AH,4FH JMP SHORT DOS_CALL GET_DIR: MOV BYTE PTR [SI],"\" ;DOS doesn't preface directory INC SI ; with slash so we must. XOR DL,DL MOV AH,47H ;Retrieve default directory. JMP SHORT DOS_CALL CHANGE_DIR: MOV AH,3BH JMP SHORT DOS_CALL PRINT_STRING: MOV AH,9 JMP SHORT DOS_CALL CK_KEY: MOV AH,0BH ;---------------------------; DOS_CALL: INT 21H RET ;---------------------------------------------------------------; ; This subroutine will systematically change directories up and ; ; down the directory tree, searching for the matching filename. ; ;---------------------------------------------------------------; GLOBAL_SEARCH: MOV DX,OFFSET SEARCHING ;Display searching message. CALL PRINT_STRING CALL PRINT_NAME ;Display filename. MOV DX,OFFSET ROOT ;Start the search from root. CALL CHANGE_DIR MOV DI,OFFSET DIR_LEVEL MOV BP,DI ;Point to first level directory. MOV AX,0101H ;Store initial level of one. MOV CX,64 / 2 REP STOSW FIRST_FILE: CALL CK_KEY ;Was a key pressed? CMP AL,0 JNZ END_SEARCHING ;If yes, abort search. CALL CK_EXECUTABLE ;Check if matching executable. JC FIRST_DIR ;If no, try next directory. RET ;Else, return to execute. PARENT_DIR: CMP BP,OFFSET DIR_LEVEL ;When we try to return to parent JNZ CONTINUE ; directory and are in root, we END_SEARCHING: STC ; are done. RET CONTINUE: MOV DX,OFFSET PARENT ;Otherwise, change CALL CHANGE_DIR ; to parent directory. MOV BYTE PTR DS:[BP],1 ;Put one back in previous level DEC BP ; and point to parent level. FIRST_DIR: XOR BL,BL ;Use BL as pointer to directory no. MOV DX,OFFSET STAR_DOT_STAR MOV CX,10H ;Ask for directory match. CALL FIND_FIRST ;Find first matching. JC PARENT_DIR CK_DIR: CMP BYTE PTR DS:[DTA+21],10H ;If not a directory, get next. JNZ NEXT_DIR CMP BYTE PTR DS:[DTA+30],'.' ;If dot directory, get next. JZ NEXT_DIR INC BL ;Increment position in directory. CMP BL,DS:[BP] ;Continue until new directory. JNZ NEXT_DIR INC BYTE PTR DS:[BP] ;Update variables. MOV DX,OFFSET DTA + 30 CALL CHANGE_DIR ;Change the directory. INC BP JMP SHORT FIRST_FILE ;See if directory has a run file. NEXT_DIR: CALL FIND_NEXT ;Get all subdirectories in current JC PARENT_DIR ; directory then go to parent. JMP SHORT CK_DIR ;---------------------------; PARAMETER LABEL BYTE FCB_5CH EQU PARAMETER + 256 FCB_6CH EQU FCB_5CH + 16 CURRENT_DIR EQU FCB_6CH + 16 WORKING_DIR EQU CURRENT_DIR + 65 DIR_LEVEL EQU WORKING_DIR + 65 FILENAME EQU DIR_LEVEL + 64 FILESPEC EQU FILENAME + 13 DTA EQU FILESPEC + 67 + 13 CODE_END EQU DTA + 43 + 256 CODE ENDS END START