docs: document why map_to_index assumes value is not 0, inf, or NaN#4930
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chimchim89 wants to merge 1 commit intoopen-telemetry:mainfrom
Open
docs: document why map_to_index assumes value is not 0, inf, or NaN#4930chimchim89 wants to merge 1 commit intoopen-telemetry:mainfrom
chimchim89 wants to merge 1 commit intoopen-telemetry:mainfrom
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Description
Replaces the FIXME comment in
ExponentMapping.map_to_indexwith a detailed explanation of whyvaluecan be assumed to not be0,inf, orNaN.Zero is represented in IEEE 754 with all exponent bits set to 0, giving
get_ieee_754_exponenta result of -1023. Since-1023 is less than
MIN_NORMAL_EXPONENT(-1022), zero is caught by the existing guard and returned early. Inf is represented in IEEE 754 with all 11 exponent bits set to 1 and a mantissa of 0, givingget_ieee_754_exponenta result of 1024 and correction a value of -1. NaN is represented in IEEE 754 with all 11 exponent bits set to 1 and a non-zero mantissa of unspecified bit pattern, producing an unspecified correction value. Inf and NaN are not caught by the guard above. As defined in theMappingbase class, callers must ensure that only finite, positive values are passed tomap_to_index.Type of change
How Has This Been Tested?
No tests required. This is a documentation-only change. No logic was modified.
Does This PR Require a Contrib Repo Change?
Checklist: