BUG: L1103 Error Caused by Incorrectly Nested Segments

• Microsoft Macro Assembler for MS-DOS, versions 6.0, 6.0a, 6.0b, 6.1, 6.1a, and 6.11

SYMPTOMS

If a simplified segment directive is used when two segments are already open, the resulting object file may generate the following error when it is linked:

   fatal error L1103: attempt to access data outside segment bounds

RESOLUTION

The code shown below illustrates a case where this problem will occur. The comment lines show how to resolve the problem by closing one or more of the nested segments.

STATUS

Microsoft has confirmed this to be a problem in MASM version 6.x. We are researching this problem and will post new information here in the Microsoft Knowledge Base as it becomes available.

MORE INFORMATION

The following code sample illustrates the problem. When the simplified directive .CODE is encountered in this sample, only one of the previously opened segments is closed and the error results. If either or both of the ENDS statements is placed in the code, the program will link correctly.

Sample Code

; Assemble options needed: none .MODEL large,c .STACK

myseg SEGMENT

    mydata WORD 1
;myseg ENDS   ; fixes the problem

    data2 WORD 2

.CODE

    .STARTUP
    ASSUME ds:myseg
    mov dx, SEG mydata
    mov ds, dx
    mov ax, mydata
    ASSUME ds:myseg2
    mov dx, SEG mydata2
    mov ds, dx
    mov ax, mydata2
    .EXIT