DATA Column in BC /A Assembly .LST Listing Is DGROUP Data (44309)


The information in this article applies to:

  • Microsoft QuickBASIC 4.0, when used with:
    • the operating system: MS-DOS
  • Microsoft QuickBASIC 4.0b, when used with:
    • the operating system: MS-DOS
  • Microsoft QuickBASIC 4.5, when used with:
    • the operating system: MS-DOS
  • Microsoft Basic Professional Development System (PDS) for MS-DOS and MS OS/2 7.0
  • Microsoft BASIC Compiler for MS-DOS and OS/2 6.0
  • Microsoft BASIC Compiler for MS-DOS and OS/2 6.0b
This article was previously published under Q44309

SUMMARY

The BC.EXE compiler supports the /A option, which outputs a listing (.LST) that shows the assembly-language code that the compiler generates for each line of the source file.

The "Data" column in this assembly-language code listing is a hexadecimal value showing how many bytes have been statically allocated in the default data segment (DGROUP).

This information applies to Microsoft QuickBasic Versions 4.00, 4.00b, and 4.50 for MS-DOS, to Microsoft Basic Compiler Versions 6.00 and 6.00b for MS-DOS and MS OS/2, and to Microsoft Basic PDS Version 7.00 for MS-DOS and MS OS/2.

MORE INFORMATION

As a demonstration, compile the following program using the BC /A option: 
   x% = 5              'Allocates 2 bytes
   y! = 100            'Allocates 4 bytes
   z# = 200            'Allocates 8 bytes
The following listing (.LST) file is generated: 
Offset  Data    Source Line
 
 0030   0006    x% = 5              'Allocates 2 bytes
 0030   0006
 0030   0006    y! = 100            'Allocates 4 bytes
 0030   0006
 0030   0006    z# = 200            'Allocates 8 bytes
 0030   0006
 0030   0006
 0030    **            I00002: mov   X%,0005h
 0036    **                    int   35h
 0038    **                    db    06h
 0039    **                    dw    <0000C842>
 003B    **                    int   35h
 003D    **                    db    1Eh
 003E    **                    dw    Y!
 0040    **                    int   3Dh
 0042    **                    int   39h
 0044    **                    db    06h
 0045    **                    dw    <0000000000006940>
 0047    **                    int   39h
 0049    **                    db    1Eh
 004A    **                    dw    Z#
 004C    **                    int   3Dh
 004E    **                    call  B$CENP
 0053   0014
The last entry in the "Data" column shows that a total of 20 bytes (6 + 2 + 4 + 8 = 20) have been allocated in near data. Note the value is shown as a hexadecimal number (0014 hex = 20 decimal).
Modification Type:MinorLast Reviewed:1/9/2003
Keywords:KB44309
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