Microsoft KB Archive/40784

= CodeView Does Not Work with Grouped Code Segments =

Article ID: 40784

Article Last Modified on 10/23/2003

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APPLIES TO


 * Microsoft CodeView 4.1
 * Microsoft CodeView 3.0
 * Microsoft CodeView 3.0
 * Microsoft CodeView 3.0
 * Microsoft CodeView 4.0
 * Microsoft CodeView 4.01
 * Microsoft CodeView 4.01
 * Microsoft CodeView 4.1
 * Microsoft CodeView 3.0
 * Microsoft CodeView 3.0
 * Microsoft CodeView 4.1
 * Microsoft CodeView 4.1
 * Microsoft CodeView 4.1

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This article was previously published under Q40784



Using the Microsoft Macro Assembler (MASM), it is possible to associate various segments into a group; DGROUP is an example of this technique. Grouped data or stack segments do not affect CodeView but CodeView does not recognize grouped code segments. The program will run correctly under CodeView but none of the CodeView functions will be available on the second and subsequent segments in the code group.

The sample code below illustrates this behavior. Once the program executes into the _TEXTB segment, all CodeView functionality is lost. You cannot set any breakpoints or single step through the _TEXTB code. Any attempt to single trace into _TEXTB will result in CodeView running all the code in _TEXTB as if you had specified a go or a step

Sample Code

 * Assembler options needed: /Zi

DOSSEG _TEXT  GROUP   _TEXTA, _TEXTB         ; Code group _TEXT

_DATA  SEGMENT WORD PUBLIC 'DATA' msg    DB      &quot;Hello, world.&quot;, 13, 10, &quot;$&quot; _DATA  ENDS

_TEXTA SEGMENT WORD PUBLIC 'CODE'     ; First code segment - this ASSUME cs:_TEXT,ds:_DATA      ;  code may be traced as start:  mov     ax, _DATA              ;  expected. mov    ds, ax        call    FAR PTR SayHi mov    ax, 4C00h int    21h _TEXTA ENDS

_TEXTB SEGMENT WORD PUBLIC 'CODE'     ; You cannot trace through SayHi  PROC                           ;  this code. mov    ah, 9h mov    dx, OFFSET msg int    21h ret SayHi  ENDP _TEXTB ENDS

END    start

Additional query words: kbinf 2.20 3.00 3.50 4.10

Keywords: kb16bitonly KB40784

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