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== Appendix C - Rationale

This appendix documents the rationale behind decisions made while creating the TOSA specification.
Explanations and definitions contained in this appendix are non-normative.

=== FP8

The operators that perform calculations on FP8 data types are limited.
Fewer mantissa bits in FP8 make it inappropriate for use in most elementwise operations such as <<ADD>>.
Support was also added to the data layout and movement operations on the understanding that no calculations are performed.
Two extensions for the FP8 types were created in order to cover both formats defined by <<OCP-OFP8,OCP-OFP8>>.

=== Transcendental Functions

In the TOSA specification, a limited number of transcendental operations are supported.
The operators supported are sufficient for common networks while minimizing the number of operations an implementation must support.
Originally, SIGMOID and TANH were added as the common functions used for activations.
ERF was added to support GELU style activation functions.
SIN and COS were added to provide a base level of trigonometric functionality as well as support for Rotary Position Embedding.

