FIX: CV 4.0 Port Input Command Does Not Display Value (87550)
The information in this article applies to:
- Microsoft CodeView for MS-DOS 4.0
- Microsoft CodeView for MS-DOS 4.01
- Microsoft CodeView for MS-DOS 4.05
This article was previously published under Q87550 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) 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.
| Modification Type: | Major | Last Reviewed: | 9/30/2003 |
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| Keywords: | kb16bitonly kbfix KB87550 |
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