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Text File | 1991-10-01 | 26.9 KB | 679 lines

╔══════════════════════════════════════════════════════════════════════════╗ ║STOP! ARRET! ALTO! HALT! STOP! ARRET! ALTO! HALT! STOP! ARRET! ALTO! HALT!║ ║ ║ ║ This program can harm your HARDWARE...! ║ ║ YOU USE IT AT YOUR OWN RISK !!! ║ ║ ABSOLUTELY NO LIABILITY ACCEPTED !!! ║ ║ ║ ║The program will not run without the appropriate parameters, so there is ║ ║LITTLE risk that you will run it accidentally. But be very careful if you ║ ║call it from a batch file...! ║ ║ ║ ║STOP! ARRET! ALTO! HALT! STOP! ARRET! ALTO! HALT! STOP! ARRET! ALTO! HALT!║ ╚══════════════════════════════════════════════════════════════════════════╝ PORTS.EXE ───────── (Ver 1.3 - 19 Sep 91) Copyright (c) and developed by José Campione 2415 SouthVale Cr. U-25, Ottawa, Ont. K1B 4T9 (613) 523-4345. and C. Robert Parkinson 5 Ramsgate, Ottawa, Ont. K1V 8M4, (613) 523-7299. Program suggested by Micheline Johnson (who also worked out the details for example #4). * * * NOTICE ══════ This program and every file distributed with it are copyright (c) by the authors, who retain authorship both of the pre-compiled and compiled codes. Their use and distribution are unrestricted, as long as nobody gets any richer in the process. Although these programs were developed to the best of the authors abilities, no guarantees can be given as to their performance. By using them, the user accepts all risks and the authors decline all liability. INTRODUCTION ════════════ PORTS.EXE is a small utility to read and/or write a byte or word value of an input/output (I/O) port. This ability will enable you to alter some of the defaults for your system operation. In particular, this program was designed to allow you to view and/or alter the CMOS configuration values in 80286 and higher systems, although it can be used for other purposes (see the WARNING below). For those users who are not familiar with the Intel/Microsoft I/O port address structure, please read the BACKGROUND section below BEFORE you use this program. WARNING ═══════ This utility can alter the basic operation of your system. DO NOT use it to write to the ports unless you thoroughly understand what you are doing. In particular, DO NOT write to any port which is concerned with disk operations. An incorrect value in another location may crash your system, but an improper value in these locations may corrupt your disk. Be very careful to not get confused between decimal and hexadecimal values. Merely reading a port may also disrupt your system operation, although it will not harm any hardware. You have been warned! SYNTAX ══════ PORTS.EXE uses five possible first parameters. The "u", "a" and "w" parameters, while they may be useful in other circumstances, were specifically created to deal with the CMOS RAM settings in 286 and higher systems. The parameters are: i = In (from port). Input/display a single byte from a port. o = Out (to port). Output/send a single byte to a port. u = Out/In (to port 1/from port 2). Output/send a single byte to a port, followed by an input/display from a second port. The optional parameter "#xxxx" (see below) permits a delay of xxxx milliseconds to be inserted between the two port accesses. a = Out/Out (to port 1/to port 2). Output/send a single byte to a port, followed by an output/send of another byte to a second port. The optional parameter "#xxxx" (see below) permits a delay of xxxx milliseconds to be inserted between the two port accesses. w = Word out (to port). Output/send a 2-byte word to a port. Usage: ───── C:\> PORTS i $INWORD <!> C:\> PORTS o $OUTWORD <byte value> <!> C:\> PORTS u $OUTWORD <byte value> $INWORD <!> C:\> PORTS a $OUTWORD <byte value> $OUTWORD <byte value> <!> C:\> PORTS w $OUTWORD <word value> <!> Where: - INWORD and OUTWORD are port addresses. These are not in the normal "segment:offset" form, but rather they are in terms of an "absolute" port address (e.g., "$061" for the speaker). The addresses can be entered as hex or decimal numbers, but hex addresses must be preceded by the "$" sign. (This is Pascal's way of indicating a hex number). - <byte value> or <word value> is the decimal or hex value that you wish written to the port. Hex values must be preceded by the "$" sign. - The optional "#xxxx" parameter will only function with the first parameters "u" and "a", when making two successive calls to ports. In the syntax for this parameter, "xxxx" represents any decimal number between (and including) 0 to 9999. A string representing a number within this range will cause a delay of "xxxx" milliseconds between the first and the second port call. Any string not representing a number within that range will cause this parameter to be ignored (i.e., no delay between the port calls). - The optional "!" parameter causes the display on the screen of the value of the last input/output byte in decimal, hex and binary formats. It will also display the delay value if "#xxxx" was used. - Any positive integer below 65536 (0 to 65535 decimal, or $0 to $FFFF hex) is a valid word. Similarly, any positive integer below 256 (0 to 255 decimal, or $00 to $FF hex) is a valid byte. When entering bytes or words, $DF is equivalent to $00DF and both are valid either as bytes or as words. - Note that parameter "u" causes two successive calls. The first one is similar to a call using parameter "o" and the second one is similar to a call using parameter "i". Similarly, parameter "a" makes two successive calls equivalent to two separate calls using parameter "o". Our testing on several systems has determined that these two successive calls (as, for example, those required to access the CMOS) could not be carried out by two successive individual commands from the DOS prompt. They require a special "single step" operation with a single call to PORTS. CMOS CONFIGURATION ══════════════════ For 80286 and higher systems, configuration information is held in battery-powered CMOS memory that retains the information even when the computer is switched off. That information, originally entered through the software setup program, can be altered with PORTS.EXE. However, to do so you must know the CMOS address and the desired value. To display bytes in CMOS, use "PORTS u" (as in the example below). To change a CMOS value, using the example below, simply use "PORTS a" to output the CMOS address (byte) into port 70h and output the desired byte value into port 71h. Example: ─────── C:\>PORTS u $70 $14 $71 ! This line causes the following display: Port byte = 35d, 0023h, 00100011b. Similarly, the same command line can be entered using decimal notation as: C:\>PORTS u 112 20 113 ! which would have caused exactly the same display. This command outputs byte $14 (a CMOS address) to port $70 and requests the input of the value currently held at that CMOS address from port $71, which in this case happens to contain byte $23. In this example, the displayed byte is the equipment byte held in the CMOS. You can interpret it as follows, remembering that bit 0 is the rightmost bit: Bits 6,7: 00 - 1 floppy drive 01 - 2 floppy drives Bits 4,5: 00 - No monitor, or EGA or better. 01 - 40 column, color. 10 - 80 column, color. 11 - monochrome. Bits 2,3: (not used) Bit 1 : 0 - math coprocessor not installed. 1 - math coprocessor installed. Bit 0 : 0 - No floppies installed. 1 - 1 or more floppies installed. ERRORLEVELS ═══════════ In all cases but one, the byte being addressed is returned as an ASCII value in the exit errorlevel. The exception is when using the "w" parameter (out a 2-byte word to a port), when the returned errorlevel will be 0. This exit errorlevel capability makes PORTS well suited for use in a batch file. Use "PORTS i" with an errorlevel test to confirm that this is the proper value to alter, then use "PORTS u" with another errorlevel test to confirm that it has indeed been changed to the value that you desire, branching to an error routine in either case if the correct errorlevel is not returned. BACKGROUND ══════════ The term "port" has two meanings, so this needs to be cleared up first. From a user perspective, "port" is normally thought of as being a hardware connector. The user is likely to consider that he has, for example, two serial ports, one parallel port and, perhaps, a mouse port and a game port. However, to a programmer the term "port" implies an access point to facilitate data transfer, in other words, an input/output (I/O) address. To contrast the two meanings, consider that one serial "port" has, in fact, eight separate but integral I/O "ports". This document is concerned solely with the I/O address meaning of the word "port". Any Intel 80x8x processor has two separate address modes, using the same addressing pins. The first mode addresses memory (i.e., normal RAM/ROM addressing). The second mode, I/O port addressing, while it uses some of the same numerical addresses as for RAM, actually sends/receives the information to or from support chips (e.g., the timer, the keyboard controller, etc.) or peripheral devices (e.g., the disk controller, the graphics adapter, etc.). All programming languages have built-in methods of differentiating between the two modes of addressing. As we said before, I/O address ports are used by DOS for data transfer. The values in these locations govern that part of the system which is external to the processor itself. Therefore, the ports allow direct access to the hardware. Through ports you can access components on the mother board, on expansion cards or even devices external to the system proper, such as modems, printers, etc. Each port will have a different meaning for each particular device and the use of any given port varies from chip to chip or device to device. Before using PORTS, check your technical documentation for the motherboard, the expansion card or the device. Although we normally speak of the ports as one generic class, they are actually divided into two types, CPU ports and DOS ports. CPU ports (also known as "logical" ports) are directly accessible to the CPU and govern such things as the speaker, keyboard, timer, disk access, etc. DOS ports are normally accessible to the processor only through the use of DOS "interrupts". They control high-level data transfer via "serial" ports (e.g., COM1) and "parallel" ports (e.g., LPT1). Understanding this difference is essential for those programmers who write at the hardware level. There are many differences in the port addressing schemes used by various Intel processors, although newer processors are always a superset of older ones. These differences are necessarily also supported by the specific ROM BIOS for that system type. Because of these differences, compatibility is normally attained by interacting with the ports only through the processor itself or through DOS/BIOS interrupts. But sometimes, in order to achieve a specific purpose, direct access to the hardware cannot be avoided; PORTS.EXE can do this for you. Each port has a specific port number, or address. In a 16-bit bus system (8086, 80286 and above) this allows 65,535 ports (0 to FFFFh). As of 1990, only port addresses 000h to 3FFh had been assigned. In an XT system, because of the 8-bit external bus, the ports are limited to a maximum of 1,024. Five kinds of operations are usually performed on ports: 1) input (receive from port) a byte; 2) output (send to port) a byte; 3) output (send to a port) a byte and input (receive) a byte from a second port in one single operation; 4) output (send to a port) a byte and output (send to the same or another port) another byte in one single operation; and 5) output (send to a port) a word (two consecutive bytes in one single step). This last "word" operation is necessary because many hardware functions are triggered immediately by any operation on the applicable port. Any attempt to send two consecutive single-byte values to this port would necessarily fail. Some port operations require two successive bytes sent to the same port, but the hardware may require a small delay between these bytes. PORTS can interpose this delay if required. Many ports are "bit-mapped", in that each bit has a specific function. For example, port 14h is the so-called "equipment byte", since it specifies, in bit values, the elementary hardware configuration of your system. Similarily, port 61h uses only the first two bits to control the speaker, the remaining six being used for unrelated purposes. Changing bit-mapped ports with PORTS is a complex operation, requiring the conversion to and from binary values. See Example #3 below. To assist in this conversion, you may wish to use the PC Magazine utility CONVERT.COM. There are also many anomalies in the way in which ports respond. These are dependent upon the hardware being addressed, the system being used, the manufacturer's design whims, etc. As these anomalies are very much system-specific, trial and error (hopefully not too much error!) is the only sure test. This small technical background is NOT designed to make you familiar with I/O ports and their usage. Please consult any reliable programmer's handbook. EXAMPLES ════════ Example #1 - Controlling the Speaker ──────────────────────────────────── Your computer's speaker is controlled by bits 0 and 1 of the bit-mapped byte found at port 61h. If both bits are set to 1 you will hear a continuous tone in the same frequency as the infamous DOS beep. To vary the tone, programs must use ports 42h and 43h to tell the system programmable timer chip how to vary the output frequency. That's beyond what we want to demonstrate here; we're just going to show you how to output sound. The remaining bits 2 to 7 of the byte at port 61h are uses for other purposes, so don't disturb these. This means that we have to first find the existing byte at that port. Do that with this command: "PORTS o $061 !" Now take the binary byte on the screen (e.g., 01001000 or 48h) and change it so that bits 0 and 1 are set to 1 (e.g., 01001011 or 4Bh). Make certain that you do not alter the other 6 bits. The easiest way to do this conversion is to use the CONVERT.COM utility from PC Magazine, but you can do it manually using the technique illustrated in Example #3. If we just output the changed byte to port 61h, we will get a continuous tone and we will then have to output the original byte to turn it off. But we can use the PORTS "a" parameter to do both, inserting a variable delay so that we can tell that our ports call does work. Using the example byte, this is the command: "PORTS a $061 $04B $061 $048 #500" Change the "#500" to vary the duration of the sound. Example #2 - Initializing the Printer ───────────────────────────────────── Here is a simple example to reset a printer connected to your system to the printer's built-in default settings, assuming that it is a parallel port Centronics-compatible printer. It also assumes that your printer is addressed through LPT1. While this type of reinitialization can more easily be done using your printer's built-in "escape" sequences, this example merely illustrates one of the capabilities of PORTS. The third of the LPT1 I/O port addresses is the one that controls the initialization (INIT) line to the printer. To initialize the printer we have to drop the normal +5V signal on that INIT line to 0V, then restore it to +5V again. To do this with a software routine, we have to determine that specific I/O address for our system, then send two sequential values to that port; one to set bit 2 to zero, then one to set bit 2 to 1. However, since the INIT line has to be held low (0V) for long enough for the printer to notice, we must either use two separate PORTS "o" calls or, preferably, use a PORTS "a" call to the same I/O address but with a delay ("#xxxx") between the two calls. Here is the routine: - To find the specific I/O address for your system, we will use DEBUG. However, you could use any other memory editor. At the DEBUG "-" prompt, enter "d 0040:0008". The values in the first two bytes are the first LPT1 I/O address. On our test system, DEBUG gave "BC 03". Remembering to reverse the order, we get an I/O address of "03BCh". But we want the THIRD I/O address, so we add 2 (in hex) to that, giving us "03BEh" as the INIT port address. - Now, we have to drop bit 2 to 0, then raise it to 1 again. So we output binary 11101000 (232) to the port. Counting from 0 on the right, you can see that bit 2 is indeed a 0. To raise bit 2 to 1, we then output binary 11101100 (236) to the same port. - We're ready to try our test. Execute the following PORTS command, remembering to substitute your own I/O port address if it differs from 03BEh: "PORTS a $03BE 232 $03BE 236 #50!" Experiment with different values for "#xxxx" to find the minimum delay that your printer requires. On the test system, for example, a delay as small as 1 millisecond was acceptable. Example #3 - Setting Bright Text Background Colours ─────────────────────────────────────────────────── Try this test if your system has a CGA card. Only use it if you have a CGA card, as it may not work with other adapters. If your VGA or SuperVGA adapter is 100% EGA compatible (e.g., the ATI VGA Wonder) this test will work. PORTS does not check for the adapter type. You can modify the blinking bit that causes blinking characters on the screen, so that, instead of blinking, it will enable the use of bright background colors. Most CGA cards can be accessed through port 03D8h ($03D8). The configuration word of the CGA card can be obtained from the BIOS (it is the word at address $0040:$0065). Usually, this word contains the value $3029 (if you look into this address using DEBUG, remember that DOS inverts the bytes in a word), which in binary is: 3 0 2 9 h 0011 0000 0010 1001 b ^ To toggle blinking, bit 5 has to be reset (indicated with the caret). This can be done by "ANDing" 3029h with $DF: 3 0 2 9 h 0011 0000 0010 1001 b AND D F h 0000 0000 1101 1111 b ^ ───────────────────── 3 0 0 9 h 0011 0000 0000 1001 b So enter the following: C:\>PORTS ! And you'll get the ports message with the blinking string "WARNING!". Then enter: C:\>PORTS w $0D38 $3009 ! If everything went smoothly, you'll see that the blinking of "WARNING!" has ceased and that, instead, it is being displayed on a bright background color. To change your display back to normal, enter: C:\>PORTS w $0D38 $3029 ! Or replace $3029 with whatever word was originally found at address $0040:$0065 in your system. Example #4 - Denying Access to Drives ───────────────────────────────────── For 286/386/486 systems only. ╔════════════════════════════════════════════════════╗ ║ CAUTION ║ ║ ─────── ║ ║ This procedure, if improperly done, can result ║ ║ in your having great difficulty accessing ║ ║ your computer system. ║ ║ ║ ║ Improper inactivation of a hard drive can be ║ ║ rectified by booting from a floppy diskette ║ ║ and restoring the CMOS from the setup diskette. ║ ║ ║ ║ Improper inactivation of floppy drives is of ║ ║ more concern. If you have provided for no way ║ ║ of restoring the CMOS from the hard drive, then ║ ║ you'll probably need to return to your dealer. ║ ║ ║ ║ UNDER NO CIRCUMSTANCES inactivate all floppy ║ ║ and hard drives. Should you do so, even your ║ ║ dealer will be very unhappy. ║ ║ ║ ╚════════════════════════════════════════════════════╝ There are several password protection programs that permit the hiding or disabling of one or more storage devices. One limitation of these programs is that they can usually be bypassed by booting with a system (bootable) diskette from the A: drive. To overcome this security limitation, it is possible to switch off the A: and B: drives by appropriate editing of the CMOS RAM. The retrieval and input of the CMOS configuration setup information from and to the CMOS EEPROM chip can be done by using the PC Magazine utilities CMOSGET and CMOSPUT. In a manual operation, the byte file generated by CMOSGET can be edited using any good binary editor and then uploaded to the system using CMOSPUT. However, PORTS permits a more elegant and practical approach: 1) Back up the complete hard drive that you wish to hide. 2) Make a copy of the CMOS RAM, using "CMOSGET > CMOS.DAT". 3) Make a bootable system diskette with the following programs (in addition to the two hidden system files) on it, which will permit everything to be put back to normal if there are any problems: COMMAND.COM CMOSPUT.COM CMOS.DAT PORTS.EXE 4) Note the contents of your CMOS RAM at address 10h (floppy drives), address 12h (hard drives) and at addresses 2E,2Fh (checksum). An example of the contents might be: - at address 10h, the value 24h (1.2M and 1.4M floppy drives). - at address 12h, the value F0h (single hard drive type Fh). - at address 2E,2Fh, the checksum value 04D4h. 5) To switch off the floppy drives, address 10h has to be cleared (subtract 24h) and to switch off the hard drive, address 12h has to be cleared (subtract F0h). Therefore, switching off the floppy drives requires a checksum of 04B0h. If you are switching off the hard drive, a checksum of 03E4h is required. 6) Put the following batch files on the hard drive: FLOFF.BAT ───────── ports a $70 $10 $71 $00 ! ports a $70 $2E $71 $04 ! ports a $70 $2F $71 $B0 ! and FLON.BAT ──────── ports a $70 $10 $71 $24 ! ports a $70 $2E $71 $04 ! ports a $70 $2F $71 $D4 ! 7) Put the following batch files on the bootable floppy diskette: HDOFF.BAT ───────── ports a $70 $12 $71 $00 ! ports a $70 $2E $71 $03 ! ports a $70 $2F $71 $E4 ! and HDON.BAT ──────── ports a $70 $12 $71 $F0 ! ports a $70 $2E $71 $04 ! ports a $70 $2F $71 $D4 ! 8) In the above examples, the CMOS RAM port addresses are $70 and $71. The parameters following $70 and $71 are the CMOS RAM internal address and the data to be written there, respectively. The "$" is the Pascal representation for hex numbers, used by PORTS. To Turn Off the Hard Drive ────────────────────────── 8) Run HDOFF from the bootable diskette in floppy drive A:. To test whether you have been successful in hiding the hard drive, do a boot, without the floppy diskette in drive A:. If your efforts have been a success, the computer will now find no hard drive, and will give the prompt: "Insert BOOT diskette in drive A:" After booting from the floppy drive, any request to log on to the hard drive causes the display of the DOS error message: "Invalid drive specification". 9) To return everything back to normal, run HDON from the floppy drive and reboot. To Turn Off the Floppy Drives ───────────────────────────── 10) Run FLOFF from the hard drive, and reboot. The computer will not even check the floppy drives to see if they contain diskettes. Instead, it will boot straight from the hard drive. A request to log on to one of the floppy drives, regardless of the presence of a diskette in that drive, causes the display of the DOS error message: "Not ready reading drive A Abort, Retry, Fail ?" 11) To return everything back to normal, run FLON from the hard drive and reboot. * * *