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 5.1.2. Symbol table

The ELFv2 ABI uses the three most-significant bits in the symbol st_other field to specify the number of bytes between a function's global entry point and local entry point. The global entry point is used when it is necessary to set up the TOC pointer (r2) for the function. The local entry point is used when r2 is known to already be valid for the function. A value of zero in these bits asserts that the function does not use r2 as TOC pointer but preserves its value. A value of one in these bits asserts that the function does not use r2 as TOC pointer and does not guarantee to preserve its value. Other values in these bits have the semantics as defined in section 3.4 of the ELFv2 ABI specification document.