as: MIPS FP ABI History

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1 9.27.9.1 History of FP ABIs
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1 The MIPS ABIs support a variety of different floating-point extensions
1 where calling-convention and register sizes vary for floating-point
1 data.  The extensions exist to support a wide variety of optional
1 architecture features.  The resulting ABI variants are generally
1 incompatible with each other and must be tracked carefully.
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1    Traditionally the use of an explicit '.gnu_attribute 4, N' directive
1 is used to indicate which ABI is in use by a specific module.  It was
1 then left to the user to ensure that command line options and the
1 selected ABI were compatible with some potential for inconsistencies.
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