as: Object Attributes
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1 8 Object Attributes
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1 'as' assembles source files written for a specific architecture into
1 object files for that architecture. But not all object files are alike.
1 Many architectures support incompatible variations. For instance,
1 floating point arguments might be passed in floating point registers if
1 the object file requires hardware floating point support--or floating
1 point arguments might be passed in integer registers if the object file
1 supports processors with no hardware floating point unit. Or, if two
1 objects are built for different generations of the same architecture,
1 the combination may require the newer generation at run-time.
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1 This information is useful during and after linking. At link time,
1 'ld' can warn about incompatible object files. After link time, tools
1 like 'gdb' can use it to process the linked file correctly.
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1 Compatibility information is recorded as a series of object
1 attributes. Each attribute has a "vendor", "tag", and "value". The
1 vendor is a string, and indicates who sets the meaning of the tag. The
1 tag is an integer, and indicates what property the attribute describes.
1 The value may be a string or an integer, and indicates how the property
1 affects this object. Missing attributes are the same as attributes with
1 a zero value or empty string value.
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1 Object attributes were developed as part of the ABI for the ARM
1 Architecture. The file format is documented in 'ELF for the ARM
1 Architecture'.
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