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198fb2a | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 | #!/usr/bin/env python3
"""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)
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