Q87550: FIX: CV 4.0 Port Input Command Does Not Display Value

Article: Q87550
Product(s): Microsoft Programming Utilities
Version(s): 4.0,4.01,4.05
Operating System(s): 
Keyword(s): kb16bitonly
Last Modified: 26-JUN-2001

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The information in this article applies to:

- Microsoft CodeView for MS-DOS, versions 4.0, 4.01, 4.05 
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SYMPTOMS
========

The Port Input (I) command should display the byte from the specified hardware
port. This feature does not work correctly in Microsoft CodeView versions 4.0,
4.01, and 4.05.

(Note: This command is only valid under MS-DOS. Under Windows, it should be
ignored, and as a result does not display a value.)

RESOLUTION
==========

You can write a function that will achieve the same result. The following is an
example. To use it to check port 2f0h, type "?in(0x2f0)" (without the quotation
marks) at the CodeView command prompt.

    #pragma check_stack(off)
     unsigned in( unsigned x ) {
        _asm {
           push dx             // save register
           mov  dx, x
           in   ax, dx
           pop  dx             // restore register
           }
     }                         // 
     #pragma check_stack()

To use this function, it must be compiled and linked with CodeView symbolic
information. It is not necessary to call this function in the program to use it
when debugging, but you must step into the program before evaluating this
function.

STATUS
======

Microsoft has confirmed this to be a problem in CodeView versions 4.0, 4.01, and
4.05. This problem was corrected in CodeView version 4.1.

Additional query words: 4.00 inp

======================================================================
Keywords          : kb16bitonly 
Technology        : kbAudDeveloper kbCodeView kbZNotKeyword3 kbCodeView400DOS kbCodeView401DOS kbCodeView405DOS
Version           : :4.0,4.01,4.05
Solution Type     : kbfix

=============================================================================

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