Metadata Programmable Tags

A system comprising:

• at least one processor;
• and
• a memory comprising code stored therein that, when executed by the at least one processor, performs a method of processing instructions comprising:
• receiving a current instruction for metadata processing performed in a metadata processing domain that is isolated from a code execution domain including the current instruction;
• and
• determining, by the metadata processing domain in connection with metadata for the current instruction, whether to allow execution of the current instruction in accordance with a set of one or more policies, wherein the one or more policies includes a set of rules that enforces execution of a complete sequence of instructions in a specified order from a first instruction of the complete sequence to a last instruction of the complete sequence, the metadata processing is implemented by a metadata processing hierarchy comprising (i) a control module, (ii) a masking module, (iii) a hash module, (iv) a rule cache lookup module, and/or (v) an output tag module.