RISC-V Design · All levels

Coverage-Driven Verification: Mechanism

Mechanism for Coverage-Driven Verification.

Mechanism to understand

Mechanism for Coverage-Driven Verification is anchored on Risk-weighted closure across functional coverage, assertion coverage, code coverage, and bug escape trend.. Convert observations into mechanism-backed decisions with explicit ownership.

Coverage-driven verification converts architecture risk into measurable closure targets for instructions, privilege modes, interrupts, memory ordering, and exception sequencing. Constrained-random stimulus and scenario weighting should be guided by uncovered bins and historical bug classes, not only raw percentage goals. Signoff readiness combines stable regressions, reviewed exclusions, and evidence that critical cross-products are hit under realistic contention so final quality is based on demonstrated behavior breadth.

Name first failing path and trigger condition.
Prove path loss with one measurable artifact.
Assign owner who can deliver smallest reversible fix.

Pipeline mechanism sketch

diagram

RISC-V PIPELINE DIAGRAM - Coverage-Driven Verification

PC -> IF -> ID -> EX -> MEM -> WB
      |     |      |      |      |
  i-cache decode  ALU/BR  LSU    regfile write
              \   |
               +-> branch resolve + redirect

Hot paths:
  - branch + load-use dependencies in ID/EX
  - memory latency stretching MEM stage
  - writeback arbitration for integer/vector units

Focus: keep control hazards predictable

Decode intent map

diagram

DECODE CONTROL MAP - Coverage-Driven Verification

opcode/funct3/funct7      controls asserted
-----------------------   ---------------------------------------
LUI / AUIPC               rd_write, imm_select(U), alu_add_pc
JAL / JALR                rd_write, pc_redirect, link_write
BRANCH                    cmp_enable, branch_type, pc_redirect
LOAD                      mem_read, rd_write, wb_sel(memory)
STORE                     mem_write, store_size, addr_calc
OP-IMM                    alu_enable, imm_select(I), rd_write
OP                        alu_enable, src2_reg, rd_write
SYSTEM / CSR              csr_readwrite, trap_check, privilege_gate
VECTOR (V extension)      vdecode, lane_mask, vtype_update

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