Data processing unit having hardware-based range encoding and decoding

A method of context-based coding, the method comprising:

• determining, by a range coder implemented in circuitry of a device, a first context value for a first context for a plurality of bits of a symbol to be coded, wherein the first context value for the first context is same for the plurality of bits;
• retrieving, by the range coder in response to a single read instruction issued to an on-chip memory, speculative probability values associated with the first context value for the first context from a table of probability values stored in the on-chip memory;
• for each bit of the plurality of bits of the symbol, determining, by the range coder, respective second context values for a second context;
• for each bit of the plurality of bits of the symbol, determining, by the range coder, respective probability values from the retrieved speculative probability values based on at least the respective second context values for the second context;
• and
• range coding, by the range coder, each bit of the plurality of bits of the symbol based on the respective determined probability values.