Module gas_cost 

Per-basic-block gas cost model (JAR v0.8.0).

Simulates a CPU pipeline to compute gas cost for a basic block. Cost = max(simulation_cycles - 3, 1).

Pipeline model:

• Reorder buffer: max 32 entries
• 4 decode slots per cycle, 5 dispatch slots per cycle
• Execution units: ALU:4, LOAD:4, STORE:4, MUL:1, DIV:1

Structs

FastCost

Compact instruction cost for the fast simulator.

Constants

DEFAULT_MEM_CYCLES

Compute FastCost from raw register bytes (no Args enum needed). For branches, extracts target from raw code bytes. Default load/store latency (L2 cache hit baseline).

Functions

fast_cost_from_decoded

Compute FastCost using pre-decoded branch target from Args.

fast_cost_from_raw

fast_cost_lut

Compute FastCost via lookup table — replaces the 256-arm match dispatch with a single array access + lightweight mask computation.

fast_cost_lut_regs

Like fast_cost_lut but takes pre-extracted register bytes to avoid re-reading code[pc+1] and code[pc+2] (already decoded by the caller).

feed_gas_direct

Feed the gas simulator directly from raw register bytes, skipping FastCost construction. Returns (is_terminator, is_branch_or_special) — the caller uses is_branch_or_special to fall back to the full path for rare cases.

gas_cost_for_block

Compute gas cost for a basic block starting at start_pc. Returns max(simulation_cycles - 3, 1).

gas_cost_for_block_decoded

gas_cost_for_block_fast

Fast gas cost computation using bitmask-based pipeline simulator.

skip_distance

Compute skip distance (bytes to next instruction start).