This re-writes the entire codebase of AluVM with two main goals:

• Remove sheer complexity of the code and ensure all pieces of business logic are as small and compact as possible, easy to unit-test, audit and document; reduce instruction set to the initial minimum possible.
• Create zk-STARK-compatible zk-AluVM version of the VM, activated with just a feature flag.

zk-AluVM design

1. ALU128 base ISA which contains just:
   • only A8-A128 registers;
   • control flow instructions;
   • EQ instruction (and no LE/LT/GE/GT);
   • data instructions: put a value into a register, clear value, test value, copy move and swap values between registers; all these ops are compatible with values being field elements;
   • no bit logic instructions.
2. GFA ISA extension:
   • adds fp read-only register contanining the used field order;
   • adds field_order to the CoreConfig with which AluVM core is initialized;
   • treats all A8-A128 registers as field elements;
   • adds arithmetic ops over finite field; if a register has a value which doesn't fit it the operation sould fail.
3. zk-aluvm feature flag which allows only zk-STARK-compatible ISA and ISA extension: ALU128 and GFA.

The new ISA architecture is described in https://docs.google.com/spreadsheets/d/1YgCYEzikUHI5cgm6XUhYdQDM1Q3-faf9NvF4y5XY0Uo/edit?gid=0#gid=0

zk-AluVM subset is highlighed on the first page in green colors (rows 2-24 and 106-110).