ProfitPress Mega CDROM2 Shareware Freeware (MSDOS)(1992)(Eng)

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Assembly Source File | 1991-10-15 | 36.6 KB | 995 lines

;--------------------------------------------------------------------------; ; Program: Ring .Asm ; ; Purpose: Rings the console bell. ; ; Notes: Compiles under TURBO Assembler, v2.0. Should work on any ; ; machine running MS-DOS, v2.xx or higher. ; ; Status: Released into the public domain. Enjoy! If you use it, ; ; let me know what you think. You don't have to send ; ; any money, just comments and suggestions. ; ; Updates: 23-Apr-89, v1.0, GAT ; ; - initial version. ; ; 22-Apr-90, v1.1, GAT ; ; - revised all procedures based on work on ASK. ; ; 05-May-90, GAT ; ; - fixed bug in handling of non-zero return codes. ; ; 13-May-90, v1.2, GAT ; ; - added '-e' option to test for nonzero errorlevels. ; ; 08-Jul-90, GAT ; ; - added macros to push/pop registers. ; ; 28-Aug-90, v1.3a, GAT ; ; - put equates and macros in separate files. ; ; - put common routines in libs. ; ; 28-Dec-90, v1.4a, GAT ; ; - added support under DOS v4.0 for '-e' option. ; ; 15-Oct-91, v1.4b, GAT ; ; - revised include file names. ; ; - added support for DOS v5.0. ; ;--------------------------------------------------------------------------; ;--------------------------------------------------------------------------; ; Author: George A. Theall ; ; Phone: +1 215 662 0558 ; ; SnailMail: TifaWARE ; ; 506 South 41st St., #3M ; ; Philadelphia, PA. 19104 USA ; ; E-Mail: theall@gdalsrv.sas.upenn.edu (Internet) ; ;--------------------------------------------------------------------------; %NEWPAGE ;--------------------------------------------------------------------------; ; D I R E C T I V E S ; ;--------------------------------------------------------------------------; DOSSEG MODEL tiny IDEAL LOCALS JUMPS ; ; This section comes from Misc.Inc. ; @16BIT EQU (@CPU AND 8) EQ 0 @32BIT EQU (@CPU AND 8) MACRO ZERO RegList ;; Zeros registers IRP Reg, <RegList> xor Reg, Reg ENDM ENDM ; ; This section comes from DOS.Inc. ; BELL EQU 7 BS EQU 8 TAB EQU 9 CR EQU 13 LF EQU 10 ESCAPE EQU 27 ; nb: ESC is a TASM keyword SPACE EQU ' ' KEY_F1 EQU 3bh KEY_F2 EQU 3ch KEY_F3 EQU 3dh KEY_F4 EQU 3eh KEY_F5 EQU 3fh KEY_F6 EQU 40h KEY_F7 EQU 41h KEY_F8 EQU 42h KEY_F9 EQU 43h KEY_F10 EQU 44h KEY_HOME EQU 47h KEY_UP EQU 48h KEY_PGUP EQU 49h KEY_LEFT EQU 4bh KEY_RIGHT EQU 4dh KEY_END EQU 4fh KEY_DOWN EQU 50h KEY_PGDN EQU 51h KEY_INS EQU 52h KEY_DEL EQU 53h KEY_C_F1 EQU 5eh KEY_C_F2 EQU 5fh KEY_C_F3 EQU 60h KEY_C_F4 EQU 61h KEY_C_F5 EQU 62h KEY_C_F6 EQU 63h KEY_C_F7 EQU 64h KEY_C_F8 EQU 65h KEY_C_F9 EQU 66h KEY_C_F10 EQU 67h KEY_C_LEFT EQU 73h KEY_C_RIGHT EQU 74h KEY_C_END EQU 75h KEY_C_PGDN EQU 76h KEY_C_HOME EQU 77h KEY_C_PGUP EQU 84h KEY_F11 EQU 85h KEY_F12 EQU 86h KEY_C_F11 EQU 89h KEY_C_F12 EQU 8ah DOS EQU 21h ; main MSDOS interrupt STDIN EQU 0 ; standard input STDOUT EQU 1 ; standard output STDERR EQU 2 ; error output STDAUX EQU 3 ; COM port STDPRN EQU 4 ; printer STRUC HOOK Vector DB ? ; vector hooked into OldISR DD ? ; entry point to old ISR NewISR DD ? ; entry point to new ISR ENDS GLOBAL at : PROC GLOBAL errmsg : PROC GLOBAL ProgName : BYTE ; needed for errmsg() GLOBAL EOL : BYTE ; ditto GLOBAL fgetc : PROC GLOBAL fputc : PROC GLOBAL fputs : PROC GLOBAL getchar : PROC GLOBAL getdate : PROC GLOBAL getswtch : PROC GLOBAL gettime : PROC GLOBAL getvdos : PROC GLOBAL getvect : PROC GLOBAL isatty : PROC GLOBAL kbhit : PROC GLOBAL pause : PROC GLOBAL putchar : PROC GLOBAL setvect : PROC GLOBAL sleep : PROC GLOBAL fake_Env : PROC GLOBAL install_TSR : PROC GLOBAL uninstall_TSR : PROC ; ; This section comes from Math.Inc. ; GLOBAL atoi : PROC GLOBAL atou : PROC GLOBAL utoa : PROC ; ; This section comes from String.Inc. ; EOS EQU 0 ; terminates strings GLOBAL isdigit : PROC GLOBAL islower : PROC GLOBAL isupper : PROC GLOBAL iswhite : PROC GLOBAL strchr : PROC GLOBAL strcmp : PROC GLOBAL strlen : PROC GLOBAL tolower : PROC GLOBAL toupper : PROC VERSION equ '1.4b' ; current version of program ERRH equ 1 ; errorlevel if help given COUNT_UPP_LIMIT equ 15 ; upper limit for rep count ; NB: This limit has also ; been coded in HelpMsg %NEWPAGE ;--------------------------------------------------------------------------; ; C O D E S E G M E N T ; ;--------------------------------------------------------------------------; CODESEG ORG 80h ; commandline LABEL CmdLen BYTE db ? LABEL CmdLine BYTE db 127 dup (?) ORG 100h ; start of .COM file STARTUPCODE jmp main ; skip over data and stack %NEWPAGE ;--------------------------------------------------------------------------; ; D A T A ; ;--------------------------------------------------------------------------; LABEL ProgName BYTE db 'ring: ', EOS LABEL EOL BYTE db '.', CR, LF, EOS LABEL HelpMsg BYTE db CR, LF DB 'TifaWARE RING, v', VERSION, ', ', ??Date db ' - rings the console bell.', CR, LF db 'Usage: ring [-options] [count]', CR, LF, LF db 'Options:', CR, LF db ' -e = ring bell only if errorlevel is non-zero', CR, LF db ' -? = display this help message', CR, LF, LF db 'count denotes a repetition count and must be between' db ' 0 and 15.', CR, LF db 'The default value of count is 3.', CR, LF, EOS LABEL Err1Msg BYTE db 'illegal option -- ' LABEL OptCh BYTE db ? db EOS LABEL Err2Msg BYTE db 'invalid repetition count -- ', EOS LABEL Err3Msg BYTE db 'unable to locate errorlevel', EOS STRUC ERRLOC ; structure holding addresses vDos DW ? ; minor SHL 8 + major Loc DW ? ; offset within segment ENDS ErrLocTbl ERRLOC <30 SHL 8 + 3, 0beaH> ; for DOS v3.30 ERRLOC <00 SHL 8 + 4, 0f2bH> ; for DOS v4.0 ERRLOC <00 SHL 8 + 5, 02a3H> ; for DOS v5.0 ERRLOC <0, 0> ; >>>must be last<<< SwitCh db '-' ; char introducing options EFlag db 0 ; flag for testing errorlevel HFlag db 0 ; flag for on-line help Count db 3 ; default number of rings RCode db 0 ; program return code %NEWPAGE ;--------------------------------------------------------------------------; ; P R O C E D U R E S ; ;--------------------------------------------------------------------------; ;---- get_ErrLvl --------------------------------------------------------; ; Purpose: Gets errorlevel from previously executed program. ; ; Notes: Thanks to Josep Fortiana Gregori (D3ESJFG0@EB0UB011) for ; ; providing a code sample from which this proc was ; ; derived and to Yan Juras for suggesting at which ; ; offset to look for this value. ; ; Requires: 8086-class CPU and DOS v3.30 or v4.0 (as sold in USA). ; ; Entry: DS = PSP address of program (OK if not changed since ; ; program started. ; ; Exit: AL = errorlevel, ; ; cf = 1 if DOS version is unsupported or DOS not found. ; ; Calls: getvdos ; ; Changes: AX, ; ; flags ; ;--------------------------------------------------------------------------; PROC get_ErrLvl push bp dx es ; Make sure a supported version of DOS is being used. call getvdos ; AL = major version mov bp, OFFSET ErrLocTbl @@NextVer: cmp [(ERRLOC PTR bp).vDOS], ax ; supported version? je SHORT @@FindPSP ; yes add bp, SIZE ErrLocTbl ; no cmp [(ERRLOC PTR bp).vDOS], 0 ; at end of table? je SHORT @@NoCanDo ; yes jmp SHORT @@NextVer ; no ; Find the PSP for the version of COMMAND.COM which called us. ; This approach relies on the observation that COMMAND.COM ; assigns its own PSP as the calling PSP at offset 16h. ; ; ; NB: Abort if calling PSP is above current PSP. This happens ; when running under an alternate shell like MKS Toolkit. @@FindPSP: mov ax, ds @@LoopBack: mov es, ax mov dx, [es:16h] ; get caller's PSP (undocumented) xchg ax, dx cmp ax, dx jb @@LoopBack ja SHORT @@NoCanDo ; avoid infinite loop if no DOS clc ; signal no error mov bp, [(ERRLOC PTR bp).Loc] mov al, [es:bp] jmp SHORT @@Fin @@NoCanDo: stc ; signal an error @@Fin: pop es dx bp ret ENDP get_ErrLvl ;---- skip_Spaces -------------------------------------------------------; ; Purpose: Skips past spaces in a string. ; ; Notes: Scanning stops with either a non-space *OR* CX = 0. ; ; Entry: DS:SI = start of string to scan. ; ; Exit: AL = next non-space character, ; ; CX is adjusted as necessary, ; ; DS:SI = pointer to next non-space. ; ; Calls: none ; ; Changes: AL, CX, SI ; ;--------------------------------------------------------------------------; PROC skip_Spaces jcxz SHORT @@Fin @@NextCh: lodsb cmp al, ' ' loopz @@NextCh jz SHORT @@Fin ; CX = 0; don't adjust inc cx ; adjust counters if cx > 0 dec si @@Fin: ret ENDP skip_Spaces ;---- get_Opt -----------------------------------------------------------; ; Purpose: Get a commandline option. ; ; Notes: none ; ; Entry: AL = option character. ; ; Exit: n/a ; ; Calls: tolower, errmsg, get_ErrLvl ; ; Changes: AX, DX, ; ; [OptCh], [HFlag], [EFlag], [RCode] ; ;--------------------------------------------------------------------------; PROC get_Opt mov [OptCh], al ; save for later call tolower ; use only lowercase in cmp. cmp al, 'e' jz SHORT @@OptE cmp al, '?' jz SHORT @@OptH mov dx, OFFSET Err1Msg ; unrecognized option call errmsg ; then *** DROP THRU *** to OptH ; Various possible options. @@OptH: mov [HFlag], 1 ; set help flag jmp SHORT @@Fin @@OptE: mov [EFlag], 1 ; conditionally ring bell call get_ErrLvl ; get earlier errorlevel jnc SHORT @@SaveErrLvl ; continue; no problems mov dx, OFFSET Err3Msg ; can't find errorlevel call errmsg jmp @@OptH @@SaveErrLvl: mov [RCode], al ; use it as our return code @@Fin: ret ENDP get_Opt ;---- get_Arg -----------------------------------------------------------; ; Purpose: Gets a non-option from the set of commandline arguments. ; ; Notes: Anything left on the commandline is user's message text. ; ; Entry: CX = count of characters left in commandline, ; ; DS:SI = pointer to argument to process. ; ; Exit: CX = count of characters left _after_ processing, ; ; DS:SI = pointer to whitespace _after_ argument. ; ; Calls: isdigit, fputs, atou ; ; Changes: CX, DX, SI ; ; [HFlag], [Count] ; ;--------------------------------------------------------------------------; PROC get_Arg call isdigit ; if not a digit, trouble! jz SHORT @@GetCount mov dx, si ; flag arg as bad xchg di, si mov al, ' ' repne scasb ; find end of argument xchg di, si jne SHORT @@BadCount dec si ; overshot so back up 1 char inc cx jmp SHORT @@BadCount ; tell user it's bad @@GetCount: mov dx, si ; save to adjust CX and if error call atou pushf ; preserve flags add cx, dx ; adjust counter sub cx, si popf ; restore flags jc SHORT @@BadCount ; error in conversion? cmp ax, COUNT_UPP_LIMIT ; too big? ja SHORT @@BadCount ; yes mov [Count], al jmp SHORT @@Fin @@BadCount: push dx mov bl, STDERR mov dx, OFFSET ProgName call fputs mov dx, OFFSET Err2Msg call fputs pop dx mov al, [si] ; save next non-digit mov [BYTE PTR si], EOS ; replace with EOS call fputs mov [si], al ; restore it mov dx, OFFSET EOL call fputs mov [HFlag], 1 jmp SHORT @@Fin @@Fin: ret ENDP get_Arg ;---- process_CmdLine ---------------------------------------------------; ; Purpose: Processes commandline arguments. ; ; Notes: A switch character by itself is ignored. ; ; No arguments whatsoever causes help flag to be set. ; ; Entry: n/a ; ; Exit: n/a ; ; Calls: skip_Spaces, get_Opt, get_Arg ; ; Changes: AX, CX, SI, ; ; DX (get_Arg), ; ; [OptCh], [HFlag], [EFlag] (get_Opt), ; ; [Count], (get_Arg), ; ; Direction flag is cleared. ; ;--------------------------------------------------------------------------; PROC process_CmdLine cld ; forward, march! ZERO ch mov cl, [CmdLen] ; length of commandline mov si, OFFSET CmdLine ; offset to start of commandline call skip_Spaces ; check if any args supplied or cl, cl jnz SHORT @@ArgLoop jmp SHORT @@Fin ; For each blank-delineated argument on the commandline... @@ArgLoop: lodsb ; next character dec cl cmp al, [SwitCh] ; is it the switch character? jnz SHORT @@NonOpt ; no ; Isolate each option and process it. Stop when a space is reached. @@OptLoop: jcxz SHORT @@Fin ; abort if nothing left lodsb dec cl cmp al, ' ' jz SHORT @@NextArg ; abort when space reached call get_Opt jmp @@OptLoop ; Process the current argument, which is *not* an option. ; Then, *drop thru* to advance to next argument. @@NonOpt: dec si ; back up one character inc cl call get_Arg ; Skip over spaces until next argument is reached. @@NextArg: call skip_Spaces or cl, cl jnz @@ArgLoop @@Fin: ret ENDP process_CmdLine ;--------------------------------------------------------------------------; ; E N T R Y P O I N T ; ;--------------------------------------------------------------------------; ;---- main --------------------------------------------------------------; ; Purpose: Main section of program. ; ; Notes: none ; ; Entry: Arguments as desired ; ; Exit: Return code as follows: ; ; 0 => program ran successfully ; ; 1 => on-line help requested ; ; or whatever previous errorlevel was if '-e' option used. ; ; Calls: process_CmdLine, fputs, putchar ; ; Changes: n/a ; ;--------------------------------------------------------------------------; main: ; Process commandline arguments. If the variable HFlag is set, then ; on-line help is displayed and the program immediately terminates. call process_CmdLine ; process commandline args cmp [HFlag], 0 ; is help needed? jz SHORT @@NoHelp ; no mov [RCode], ERRH ; yes, so set return code mov bx, STDERR mov dx, OFFSET HelpMsg ; point to help message call fputs ; display it jmp SHORT @@Fin ; and jump to end of program ; Figure out whether to ring bell conditionally. @@NoHelp: cmp [EFlag], 0 ; is it conditional? jz SHORT @@RingBell ; no cmp [RCode], 0 ; yes, was errorlevel 0? jz SHORT @@Fin ; yes, no bell ; Determine how many times to ring the bell and do it. @@RingBell: mov cl, [Count] ; get the count ZERO ch ; zero out high byte of word jcxz SHORT @@Fin mov dl, BELL @@RingLoop: call putchar loop @@RingLoop ; repeat as necessary ; Ok, let's terminate the program and exit with proper return code. @@Fin: mov al, [RCode] mov ah, 4ch int DOS EVEN Buffer db ? ; space for single character ; nb: shared by fgetc() & fputc() ;-------------------------------------------------------------------------; ; Purpose: Reads a character from specified device. ; Notes: No checks are done on BX's validity. ; Buffer is shared by fputc(). Do *NOT* use in a ; multitasking environment like DESQview. ; Requires: 8086-class CPU and DOS v2.0 or better. ; Entry: BX = device handle. ; Exit: AL = character, ; Carry flag set on error (AX holds error code). ; Calls: none ; Changes: AX ; flags ;-------------------------------------------------------------------------; PROC fgetc push cx dx IF @DataSize NE 0 push ds mov ax, @data mov ds, ax ENDIF mov dx, OFFSET Buffer ; point to storage mov cx, 1 ; only need 1 char mov ah, 3fh int DOS ; get it jc SHORT @@Fin ; abort on error mov al, [Buffer] @@Fin: IF @DataSize NE 0 pop ds ENDIF pop dx cx ret ENDP fgetc ;-------------------------------------------------------------------------; ; Purpose: Writes a character to specified device. ; Notes: No checks are done on BX's validity. ; Buffer is shared by fputc(). Do *NOT* use in a ; multitasking environment like DESQview. ; Requires: 8086-class CPU and DOS v2.0 or better. ; Entry: AL = character to display, ; BX = device handle. ; Exit: AL = 1 if successful, ; Carry flag set on error (AX holds error code). ; Calls: none ; Changes: AX ;-------------------------------------------------------------------------; PROC fputc push cx dx IF @DataSize NE 0 push ds mov dx, @data mov ds, ax ENDIF mov dx, OFFSET Buffer ; point to storage mov [Buffer], al ; save char mov cx, 1 ; only write 1 char mov ah, 40h int DOS IF @DataSize NE 0 pop ds ENDIF pop dx cx ret ENDP fputc ;-------------------------------------------------------------------------; ; Purpose: Reads a character from STDIN. ; Notes: Character is echoed to display. ; Requires: 8086-class CPU and DOS v1.0 or better. ; Entry: n/a ; Exit: AL = character. ; Calls: none ; Changes: AX ;-------------------------------------------------------------------------; PROC getchar mov ah, 1 int DOS ret ENDP getchar ;-------------------------------------------------------------------------; ; Purpose: Writes a character to STDOUT device. ; Notes: none ; Requires: 8086-class CPU and DOS v1.0 or better. ; Entry: DL = character to display. ; Exit: n/a ; Calls: none ; Changes: none ;-------------------------------------------------------------------------; PROC putchar push ax mov ah, 2 int DOS pop ax ret ENDP putchar ;-------------------------------------------------------------------------; ; Purpose: Checks if a character is ready for input from STDIN. ; Notes: none ; Requires: 8086-class CPU and DOS v1.0 or better. ; Entry: n/a ; Exit: zf = 1 if character available. ; Calls: none ; Changes: flags ;-------------------------------------------------------------------------; PROC kbhit push ax mov ah, 0bh int DOS cmp al, 0ffh ; AL = FFh if character ready pop ax ret ENDP kbhit EVEN ;-------------------------------------------------------------------------; ; Purpose: Writes an ASCIIZ string to specified device. ; Notes: A zero-length string doesn't seem to cause problems when ; this output function is used. ; Requires: 8086-class CPU and DOS v2.0 or better. ; Entry: BX = device handle, ; DS:DX = pointer to string. ; Exit: Carry flag set if EOS wasn't found or handle is invalid. ; Calls: strlen ; Changes: none ;-------------------------------------------------------------------------; PROC fputs push ax cx di IF @DataSize NE 0 push es mov ax, ds mov es, ax ENDIF mov di, dx call strlen ; set CX = length of string jc SHORT @@Fin ; abort if problem finding end mov ah, 40h ; MS-DOS raw output function int DOS @@Fin: IF @DataSize NE 0 pop es ENDIF pop di cx ax ret ENDP fputs EVEN ;-------------------------------------------------------------------------; ; Purpose: Writes an error message to stderr. ; Notes: none ; Requires: 8086-class CPU and DOS v2.0 or better. ; Entry: DS:DX = pointer to error message. ; Exit: n/a ; Calls: fputs ; Changes: none ;-------------------------------------------------------------------------; PROC errmsg push bx dx mov bx, STDERR mov dx, OFFSET ProgName ; display program name call fputs pop dx ; recover calling parameters push dx ; and save again to avoid change call fputs ; display error message mov dx, OFFSET EOL call fputs pop dx bx ret ENDP errmsg EVEN ;-------------------------------------------------------------------------; ; Purpose: Gets version of DOS currently running. ; Notes: none ; Requires: 8086-class CPU and DOS v2.0 or better. ; Entry: n/a ; Exit: AL = major version number, ; AH = minor version number (2.1 = 10). ; Calls: none ; Changes: AX ;-------------------------------------------------------------------------; PROC getvdos push bx cx ; DOS destroys bx and cx! mov ah, 30h int DOS pop cx bx ret ENDP getvdos EVEN ;-------------------------------------------------------------------------; ; Purpose: Converts string of digits to an *unsigned* integer in ; range [0, 65535]. ; Notes: Conversion stops with first non-numeric character. ; Requires: 8086-class CPU. ; Entry: DS:SI = pointer to string of digits. ; Exit: AX = unsigned integer (garbage if cf = 1), ; DS:SI = pointer to first non-digit found, ; cf = 1 if number is too big. ; Calls: none ; Changes: AX, SI ; flags ;-------------------------------------------------------------------------; PROC atou push bx cx dx ; DX destroyed by MUL below ZERO ax ; AX = digit to convert ZERO bx ; BX = integer word mov cx, 10 ; CX = conversion factor @@NextCh: mov bl, [si] ; get character cmp bl, '0' ; test if a digit jb SHORT @@Fin cmp bl, '9' ja SHORT @@Fin inc si ; bump up pointer mul cx ; multiply old result by 10 jc SHORT @@Overflow sub bl, '0' ; convert digit add ax, bx ; add current value jnc @@NextCh ; continue unless result too big @@Overflow: ZERO cx ; denotes overflow jmp @@NextCh @@Fin: cmp cx, 10 ; cf = (cx != 10) pop dx cx bx ret ENDP atou EVEN ;-------------------------------------------------------------------------; ; Purpose: Tests if character is a valid ASCII digit. ; Notes: none ; Requires: 8086-class CPU. ; Entry: AL = character to be tested. ; Exit: Zero flag set if true, cleared otherwise. ; Calls: none ; Changes: flags ;-------------------------------------------------------------------------; PROC isdigit cmp al, '0' ; if < '0' zf = 0 jb SHORT @@Fin cmp al, '9' ; if > '9' zf = 0 ja SHORT @@Fin cmp al, al ; set Z flag @@Fin: ret ENDP isdigit ;-------------------------------------------------------------------------; ; Purpose: Tests if character is lowercase. ; Notes: none ; Requires: 8086-class CPU. ; Entry: AL = character to be tested. ; Exit: Zero flag set if true, cleared otherwise. ; Calls: none ; Changes: flags ;-------------------------------------------------------------------------; PROC islower cmp al, 'a' ; if < 'a' zf = 0 jb SHORT @@Fin cmp al, 'z' ; if > 'z' zf = 0 ja SHORT @@Fin cmp al, al ; set Z flag @@Fin: ret ENDP islower ;-------------------------------------------------------------------------; ; Purpose: Tests if character is uppercase. ; Notes: none ; Requires: 8086-class CPU. ; Entry: AL = character to be tested. ; Exit: Zero flag set if true, cleared otherwise. ; Calls: none ; Changes: flags ;-------------------------------------------------------------------------; PROC isupper cmp al, 'A' ; if < 'A' zf = 0 jb SHORT @@Fin cmp al, 'Z' ; if > 'Z' zf = 0 ja SHORT @@Fin cmp al, al ; set Z flag @@Fin: ret ENDP isupper ;-------------------------------------------------------------------------; ; Purpose: Tests if character is an ASCII whitespace. ; Notes: none ; Requires: 8086-class CPU. ; Entry: AL = character to be tested. ; Exit: Zero flag set if true, cleared otherwise. ; Calls: none ; Changes: flags ;-------------------------------------------------------------------------; PROC iswhite cmp al, SPACE ; if == SPACE then zf = 1 jz SHORT @@Fin cmp al, TAB ; if == TAB then zf = 1 jz SHORT @@Fin cmp al, LF ; if == LF then zf = 1 jz SHORT @@Fin cmp al, CR ; if == CR then zf = 1 @@Fin: ret ENDP iswhite EVEN ;-------------------------------------------------------------------------; ; Purpose: Converts character to lowercase. ; Notes: none ; Requires: 8086-class CPU. ; Entry: AL = character to be converted. ; Exit: AL = converted character. ; Calls: none ; Changes: AL ; flags ;-------------------------------------------------------------------------; PROC tolower cmp al, 'A' ; if < 'A' then done jb SHORT @@Fin cmp al, 'Z' ; if > 'Z' then done ja SHORT @@Fin or al, 20h ; make it lowercase @@Fin: ret ENDP tolower ;-------------------------------------------------------------------------; ; Purpose: Converts character to uppercase. ; Notes: none ; Requires: 8086-class CPU. ; Entry: AL = character to be converted. ; Exit: AL = converted character. ; Calls: none ; Changes: AL ; flags ;-------------------------------------------------------------------------; PROC toupper cmp al, 'a' ; if < 'a' then done jb SHORT @@Fin cmp al, 'z' ; if > 'z' then done ja SHORT @@Fin and al, not 20h ; make it lowercase @@Fin: ret ENDP toupper EVEN ;-------------------------------------------------------------------------; ; Purpose: Calculates length of an ASCIIZ string. ; Notes: Terminal char is _not_ included in the count. ; Requires: 8086-class CPU. ; Entry: ES:DI = pointer to string. ; Exit: CX = length of string, ; cf = 0 and zf = 1 if EOS found, ; cf = 1 and zf = 0 if EOS not found within segment. ; Calls: none ; Changes: CX, ; flags ;-------------------------------------------------------------------------; PROC strlen push ax di pushf cld ; scan forward only mov al, EOS ; character to search for mov cx, di ; where are we now not cx ; what's left in segment - 1 push cx ; save char count repne scasb je SHORT @@Done scasb ; test final char dec cx ; avoids trouble with "not" below @@Done: pop ax ; get original count sub cx, ax ; subtract current count not cx ; and invert it popf ; restore df dec di cmp [BYTE PTR es:di], EOS je SHORT @@Fin ; cf = 0 if equal stc ; set cf => error @@Fin: pop di ax ret ENDP strlen END