FIX: ESP Not Updated Correctly After PUSHFD, POPFD (87549)

The information in this article applies to:

Microsoft CodeView for MS-DOS
Microsoft CodeView for OS/2
Microsoft CodeView for Windows

This article was previously published under Q87549

SYMPTOMS

When single-stepping through a PUSHFD or a POPFD in Microsoft CodeView versions 3.0, 3.11, 3.12, 3.14, 3.5, 4.0, 4.01, and 4.05 the ESP register is changed by only 2 bytes rather than 4 bytes.

RESOLUTION

The problem only occurs when single-stepping. Placing the cursor on the next instruction and pressing F7 will result in CodeView correctly updating the ESP register. If you use this workaround, make sure the next instruction does not modify the stack pointer.

STATUS

Microsoft has confirmed this to be a problem in CodeView versions 3.0, 3.11, 3.12, 3.14, 3.5, 4.0, 4.01, and 4.05. This problem was corrected in CodeView version 4.1.

MORE INFORMATION

The following sample code demonstrates the problem. Single-step over the instructions to see ESP change by only 2 bytes. Restart and run to the first NOP and then the second to see that ESP is then correctly updated.

Sample Code

; Assembly options needed: /Zi

_text segment word public 'code'
   ASSUME cs:_text, ds:_text
.386
   PUSHFD
   NOP
   POPFD
   NOP

   MOV ah, 4ch
   INT 21h
_text ENDS
   END

Modification Type:	Major	Last Reviewed:	11/17/2003
Keywords:	kb16bitonly kbfix KB87549