nx_decoder_imm_mem_test.nx

nx_decoder_imm_mem_test.nx -- FUNCTIONAL gate-level verify of the I/S/B/U/J immediate decoders. Builds nx_decoder_imm_build into a MEM sink, runs the gate-sim over 200 random instructions and diffs each immediate net against the behavioral oracle nx_rv64im_imm_i/s/b/u/j (sign-extension included -- the gate ORs the extend mask exactly as the oracle). Per-format mismatch counts must all be 0. KAT: I-imm of addi x1,x0,-1 (0xFFF00093) = -1. Sovereign. license_tier: ORIGINAL expect_exit: 0