Configurable function approximation based on hardware selection of mapping table content

A system comprising:

• a controller;
• a plurality of multiplexors;
• configurable arithmetic circuits;
• and
• a mapping table that stores a set of function parameters;
• wherein the controller:
• sends a control signal that indicates a first mode of operation or a second mode of operation;
• in the first mode of operation:
• configures the plurality of multiplexors to forward the set of function parameters to the arithmetic circuits;
• and
• configures the arithmetic circuits to:
• compute a first approximation result of a function at an input value based on the set of function parameters;
• and
• output the first approximation result;
• in the second mode of operation:
• configures the plurality of multiplexors to forward a subset of the set of function parameters to the arithmetic circuits;
• and
• configures the arithmetic circuits to:
• compute a second approximation result of the function at the input value based on the subset of the set of function parameters;
• perform post-processing of the second approximation result to generate post-processed second approximation result, wherein the post-processing of the second approximation result includes quantizing the second approximation result;
• and
• output the post-processed second approximation result, wherein the arithmetic circuits are configured to use the plurality of multiplexors to switch between (i) converting the input value represented in a first integer format into the first approximation result represented in a floating point format in the first mode of operation and (ii) converting the input value represented in the first integer format into the post-processed second approximation result represented in a second integer format in the second mode of operation, wherein the second integer format includes fewer bits than the first integer format.

A method comprising:

• receiving an input value;
• selecting, based on the input value, a bucket of a mapping table that stores a set of function parameters associated with a base value;
• receiving a control signal that indicates either a first mode of operation or a second mode of operation;
• in the first mode of operation, using arithmetic circuits to perform a first operation by:
• obtaining the set of function parameters from the bucket;
• extrapolating the set of function parameters from the base value to the input value to compute a first approximation result;
• and
• outputting the first approximation result;
• and
• in the second mode of operation, using the arithmetic circuits to perform a second operation by:
• obtaining a subset of the set of function parameters from the bucket;
• extrapolating the subset of the set of function parameters from the base value to the input value to compute a second approximation result;
• quantizing the second approximation result to generate a quantized second approximation result;
• and
• outputting the quantized second approximation result, wherein the arithmetic circuits are configured to use the plurality of multiplexors to switch between (i) converting the input value represented in a first integer format into the first approximation result represented in a floating point format in the first mode of operation and (ii) converting the input value represented in the first integer format into the quantized second approximation result represented in a second integer format in the second mode of operation, wherein the second integer format includes fewer bits than the first integer format.