litex/migen/fhdl/verilog.py

337 lines
9.7 KiB
Python

from functools import partial
from operator import itemgetter
from migen.fhdl.structure import *
from migen.fhdl.structure import _Operator, _Slice, _Assign, _Fragment
from migen.fhdl.tools import *
from migen.fhdl.bitcontainer import bits_for, flen
from migen.fhdl.namer import Namespace, build_namespace
def _printsig(ns, s):
if s.signed:
n = "signed "
else:
n = ""
if flen(s) > 1:
n += "[" + str(flen(s)-1) + ":0] "
n += ns.get_name(s)
return n
def _printintbool(node):
if isinstance(node, bool):
if node:
return "1'd1", False
else:
return "1'd0", False
elif isinstance(node, int):
if node >= 0:
return str(bits_for(node)) + "'d" + str(node), False
else:
nbits = bits_for(node)
return str(nbits) + "'sd" + str(2**nbits + node), True
else:
raise TypeError
def _printexpr(ns, node):
if isinstance(node, (int, bool)):
return _printintbool(node)
elif isinstance(node, Signal):
return ns.get_name(node), node.signed
elif isinstance(node, _Operator):
arity = len(node.operands)
r1, s1 = _printexpr(ns, node.operands[0])
if arity == 1:
if node.op == "-":
if s1:
r = node.op + r1
else:
r = "-$signed({1'd0, " + r1 + "})"
s = True
else:
r = node.op + r1
s = s1
elif arity == 2:
r2, s2 = _printexpr(ns, node.operands[1])
if node.op not in ["<<<", ">>>"]:
if s2 and not s1:
r1 = "$signed({1'd0, " + r1 + "})"
if s1 and not s2:
r2 = "$signed({1'd0, " + r2 + "})"
r = r1 + " " + node.op + " " + r2
s = s1 or s2
elif arity == 3:
assert node.op == "m"
r2, s2 = _printexpr(ns, node.operands[1])
r3, s3 = _printexpr(ns, node.operands[2])
if s2 and not s3:
r3 = "$signed({1'd0, " + r3 + "})"
if s3 and not s2:
r2 = "$signed({1'd0, " + r2 + "})"
r = r1 + " ? " + r2 + " : " + r3
s = s2 or s3
else:
raise TypeError
return "(" + r + ")", s
elif isinstance(node, _Slice):
# Verilog does not like us slicing non-array signals...
if isinstance(node.value, Signal) \
and flen(node.value) == 1 \
and node.start == 0 and node.stop == 1:
return _printexpr(ns, node.value)
if node.start + 1 == node.stop:
sr = "[" + str(node.start) + "]"
else:
sr = "[" + str(node.stop-1) + ":" + str(node.start) + "]"
r, s = _printexpr(ns, node.value)
return r + sr, s
elif isinstance(node, Cat):
l = [_printexpr(ns, v)[0] for v in reversed(node.l)]
return "{" + ", ".join(l) + "}", False
elif isinstance(node, Replicate):
return "{" + str(node.n) + "{" + _printexpr(ns, node.v)[0] + "}}", False
else:
raise TypeError("Expression of unrecognized type: "+str(type(node)))
(_AT_BLOCKING, _AT_NONBLOCKING, _AT_SIGNAL) = range(3)
def _printnode(ns, at, level, node):
if node is None:
return ""
elif isinstance(node, _Assign):
if at == _AT_BLOCKING:
assignment = " = "
elif at == _AT_NONBLOCKING:
assignment = " <= "
elif is_variable(node.l):
assignment = " = "
else:
assignment = " <= "
return "\t"*level + _printexpr(ns, node.l)[0] + assignment + _printexpr(ns, node.r)[0] + ";\n"
elif isinstance(node, (list, tuple)):
return "".join(list(map(partial(_printnode, ns, at, level), node)))
elif isinstance(node, If):
r = "\t"*level + "if (" + _printexpr(ns, node.cond)[0] + ") begin\n"
r += _printnode(ns, at, level + 1, node.t)
if node.f:
r += "\t"*level + "end else begin\n"
r += _printnode(ns, at, level + 1, node.f)
r += "\t"*level + "end\n"
return r
elif isinstance(node, Case):
if node.cases:
r = "\t"*level + "case (" + _printexpr(ns, node.test)[0] + ")\n"
css = sorted([(k, v) for (k, v) in node.cases.items() if k != "default"], key=itemgetter(0))
for choice, statements in css:
r += "\t"*(level + 1) + _printexpr(ns, choice)[0] + ": begin\n"
r += _printnode(ns, at, level + 2, statements)
r += "\t"*(level + 1) + "end\n"
if "default" in node.cases:
r += "\t"*(level + 1) + "default: begin\n"
r += _printnode(ns, at, level + 2, node.cases["default"])
r += "\t"*(level + 1) + "end\n"
r += "\t"*level + "endcase\n"
return r
else:
return ""
else:
raise TypeError("Node of unrecognized type: "+str(type(node)))
def _list_comb_wires(f):
r = set()
groups = group_by_targets(f.comb)
for g in groups:
if len(g[1]) == 1 and isinstance(g[1][0], _Assign):
r |= g[0]
return r
def _printheader(f, ios, name, ns):
sigs = list_signals(f) | list_special_ios(f, True, True, True)
special_outs = list_special_ios(f, False, True, True)
inouts = list_special_ios(f, False, False, True)
targets = list_targets(f) | special_outs
wires = _list_comb_wires(f) | special_outs
r = "module " + name + "(\n"
firstp = True
for sig in sorted(ios, key=lambda x: x.huid):
if not firstp:
r += ",\n"
firstp = False
if sig in inouts:
r += "\tinout " + _printsig(ns, sig)
elif sig in targets:
if sig in wires:
r += "\toutput " + _printsig(ns, sig)
else:
r += "\toutput reg " + _printsig(ns, sig)
else:
r += "\tinput " + _printsig(ns, sig)
r += "\n);\n\n"
for sig in sorted(sigs - ios, key=lambda x: x.huid):
if sig in wires:
r += "wire " + _printsig(ns, sig) + ";\n"
else:
r += "reg " + _printsig(ns, sig) + ";\n"
r += "\n"
return r
def _printcomb(f, ns, display_run):
r = ""
if f.comb:
# Generate a dummy event to get the simulator
# to run the combinatorial process once at the beginning.
syn_off = "// synthesis translate_off\n"
syn_on = "// synthesis translate_on\n"
dummy_s = Signal(name_override="dummy_s")
r += syn_off
r += "reg " + _printsig(ns, dummy_s) + ";\n"
r += "initial " + ns.get_name(dummy_s) + " <= 1'd0;\n"
r += syn_on
groups = group_by_targets(f.comb)
for n, g in enumerate(groups):
if len(g[1]) == 1 and isinstance(g[1][0], _Assign):
r += "assign " + _printnode(ns, _AT_BLOCKING, 0, g[1][0])
else:
dummy_d = Signal(name_override="dummy_d")
r += "\n" + syn_off
r += "reg " + _printsig(ns, dummy_d) + ";\n"
r += syn_on
r += "always @(*) begin\n"
if display_run:
r += "\t$display(\"Running comb block #" + str(n) + "\");\n"
for t in g[0]:
r += "\t" + ns.get_name(t) + " <= " + _printexpr(ns, t.reset)[0] + ";\n"
r += _printnode(ns, _AT_NONBLOCKING, 1, g[1])
r += syn_off
r += "\t" + ns.get_name(dummy_d) + " <= " + ns.get_name(dummy_s) + ";\n"
r += syn_on
r += "end\n"
r += "\n"
return r
def _printsync(f, ns):
r = ""
for k, v in sorted(f.sync.items(), key=itemgetter(0)):
if f.clock_domains[k].rst is None:
r += "initial begin\n"
r += _printnode(ns, _AT_SIGNAL, 1, generate_reset(ResetSignal(k), v))
r += "end\n\n"
r += "always @(posedge " + ns.get_name(f.clock_domains[k].clk) + ") begin\n"
r += _printnode(ns, _AT_SIGNAL, 1, v)
r += "end\n\n"
return r
def _call_special_classmethod(overrides, obj, method, *args, **kwargs):
cl = obj.__class__
if cl in overrides:
cl = overrides[cl]
if hasattr(cl, method):
return getattr(cl, method)(obj, *args, **kwargs)
else:
return None
def _lower_specials_step(overrides, specials):
f = _Fragment()
lowered_specials = set()
for special in sorted(specials, key=lambda x: x.huid):
impl = _call_special_classmethod(overrides, special, "lower")
if impl is not None:
f += impl.get_fragment()
lowered_specials.add(special)
return f, lowered_specials
def _can_lower(overrides, specials):
for special in specials:
cl = special.__class__
if cl in overrides:
cl = overrides[cl]
if hasattr(cl, "lower"):
return True
return False
def _lower_specials(overrides, specials):
f, lowered_specials = _lower_specials_step(overrides, specials)
while _can_lower(overrides, f.specials):
f2, lowered_specials2 = _lower_specials_step(overrides, f.specials)
f += f2
lowered_specials |= lowered_specials2
f.specials -= lowered_specials2
return f, lowered_specials
def _printspecials(overrides, specials, ns):
r = ""
for special in sorted(specials, key=lambda x: x.huid):
pr = _call_special_classmethod(overrides, special, "emit_verilog", ns)
if pr is None:
raise NotImplementedError("Special " + str(special) + " failed to implement emit_verilog")
r += pr
return r
def _printinit(f, ios, ns):
r = ""
signals = (list_signals(f) | list_special_ios(f, True, False, False)) \
- ios \
- list_targets(f) \
- list_special_ios(f, False, True, True)
wires = (_list_comb_wires(f) | list_special_ios(f, True, False, False)) \
- ios \
- list_targets(f) \
- list_special_ios(f, False, True, True)
if signals:
for s in sorted(signals, key=lambda x: x.huid):
if s in wires:
r += "assign" + ns.get_name(s) + " = " + _printexpr(ns, s.reset)[0] + ";\n"
r += "always @(*) begin\n"
for s in sorted(signals, key=lambda x: x.huid):
if s not in wires:
r += "\t" + ns.get_name(s) + " <= " + _printexpr(ns, s.reset)[0] + ";\n"
r += "end\n"
return r
def convert(f, ios=None, name="top",
return_ns=False,
special_overrides=dict(),
create_clock_domains=True,
display_run=False):
if not isinstance(f, _Fragment):
f = f.get_fragment()
if ios is None:
ios = set()
for cd_name in list_clock_domains(f):
try:
f.clock_domains[cd_name]
except KeyError:
if create_clock_domains:
cd = ClockDomain(cd_name)
f.clock_domains.append(cd)
ios |= {cd.clk, cd.rst}
else:
raise KeyError("Unresolved clock domain: '"+cd_name+"'")
f = lower_complex_slices(f)
insert_resets(f)
f = lower_basics(f)
fs, lowered_specials = _lower_specials(special_overrides, f.specials)
f += lower_basics(fs)
ns = build_namespace(list_signals(f) \
| list_special_ios(f, True, True, True) \
| ios)
r = "/* Machine-generated using Migen */\n"
r += _printheader(f, ios, name, ns)
r += _printcomb(f, ns, display_run)
r += _printsync(f, ns)
r += _printspecials(special_overrides, f.specials - lowered_specials, ns)
r += _printinit(f, ios, ns)
r += "endmodule\n"
if return_ns:
return r, ns
else:
return r