| |
| """Decide which detected memories are idiomatic as ASAP7 SRAM macros. |
| |
| A memory below these floors is cheaper as flip-flops than as an SRAM |
| macro (the macro pays a fixed control/decode/sense-amp floor), and a |
| memory with too many ports has no single-macro implementation in |
| ordinary SRAM compilers. Rejected memories keep `idiomatic: false` plus |
| a reason in memories.json and synthesize as flops. |
| |
| The thresholds are deliberately simple, first-pass policy. Banking and |
| multi-port decomposition (splitting a too-wide/too-ported memory across |
| several macros) are not handled — a future extension. A user who wants |
| a rejected memory converted anyway overrides it via a `.memories` file |
| listed in ADDITIONAL_MEMORIES. |
| """ |
|
|
| from __future__ import annotations |
|
|
| import schema |
|
|
| MIN_ROWS = 16 |
| MIN_BITS_TOTAL = 256 |
| MAX_TOTAL_PORTS = 4 |
|
|
|
|
| def judge(mem: schema.Memory) -> tuple[bool, str]: |
| """Return (idiomatic, reason).""" |
| if mem.bits < 1: |
| return False, "no data pins" |
| if mem.rows < MIN_ROWS: |
| return False, f"depth {mem.rows} below macro floor {MIN_ROWS}" |
| total_bits = mem.rows * mem.bits |
| if total_bits < MIN_BITS_TOTAL: |
| return ( |
| False, |
| f"capacity {total_bits} bits below macro floor " f"{MIN_BITS_TOTAL}", |
| ) |
| if mem.total_ports() > MAX_TOTAL_PORTS: |
| return ( |
| False, |
| f"{mem.total_ports()} ports exceeds single-macro " |
| f"limit {MAX_TOTAL_PORTS}", |
| ) |
| return True, "meets ASAP7 macro floors" |
|
|
|
|
| def apply(memories: list[schema.Memory]) -> None: |
| for mem in memories: |
| mem.idiomatic, mem.reason = judge(mem) |
|
|
