Microsoft KB Archive/30500

= Segment Relative Versus Group Relative =

Article ID: 30500

Article Last Modified on 11/19/2003

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APPLIES TO


 * Microsoft Macro Assembler 5.1 Standard Edition

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This article was previously published under Q30500



SUMMARY
The following sample code will be used to explain segment relative and group relative: dgroup GROUP   aseg,cseg ASSUME cs:dgroup,ds:dgroup aseg   SEGMENT public  byte    'CODE' org 100h start: data_pointer   dw  the_data aseg   ends cseg   SEGMENT public  byte    'CODE' the_data   label   byte cseg   ends end start When defining data, fixups are relative to the start of the segment. The variable data_pointer will have an address relative to the start of the aseg segment. If you want the variable to have an address relative to the start of the group, you can explicitly state the offset relative to dgroup as follows. data_pointer   dw  offset  dgroup:the_data The exception is when you are using simplified segment directives. In that case, group relative fixups always are used rather than segment relative.

In code segments, fixups are relative to either segment or group depending on the ASSUME statements. In other words, the ASSUME STATEMENT is checked before the fixup is generated. The exception here is the same as above. When using simplified segment directives, group relative fixups are the default.

The OFFSET operator is segment relative and is discussed further in the following article in the Microsoft Knowledge Base:

30517 OFFSET Operator Is Segment Relative

Additional query words: 5.10

Keywords: KB30500

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