litex/migen/fhdl/verilog.py

232 lines
6.2 KiB
Python

from functools import partial
from migen.fhdl.structure import *
from migen.fhdl.structure import _Operator, _Slice, _Assign, _StatementList
from migen.fhdl.tools import *
from migen.fhdl.namer import Namespace, build_pnd
def _printsig(ns, s):
if s.bv.signed:
n = "signed "
else:
n = ""
if s.bv.width > 1:
n += "[" + str(s.bv.width-1) + ":0] "
n += ns.get_name(s)
return n
def _printexpr(ns, node):
if isinstance(node, Constant):
if node.n >= 0:
return str(node.bv) + str(node.n)
else:
return "-" + str(node.bv) + str(-self.n)
elif isinstance(node, Signal):
return ns.get_name(node)
elif isinstance(node, _Operator):
arity = len(node.operands)
if arity == 1:
r = node.op + _printexpr(ns, node.operands[0])
elif arity == 2:
r = _printexpr(ns, node.operands[0]) + " " + node.op + " " + _printexpr(ns, node.operands[1])
else:
raise TypeError
return "(" + r + ")"
elif isinstance(node, _Slice):
if node.start + 1 == node.stop:
sr = "[" + str(node.start) + "]"
else:
sr = "[" + str(node.stop-1) + ":" + str(node.start) + "]"
return _printexpr(ns, node.value) + sr
elif isinstance(node, Cat):
l = list(map(partial(_printexpr, ns), node.l))
l.reverse()
return "{" + ", ".join(l) + "}"
elif isinstance(node, Replicate):
return "{" + str(node.n) + "{" + _printexpr(ns, node.v) + "}}"
else:
raise TypeError
(_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) + assignment + _printexpr(ns, node.r) + ";\n"
elif isinstance(node, _StatementList):
return "".join(list(map(partial(_printnode, ns, at, level), node.l)))
elif isinstance(node, If):
r = "\t"*level + "if (" + _printexpr(ns, node.cond) + ") begin\n"
r += _printnode(ns, at, level + 1, node.t)
if node.f.l:
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):
r = "\t"*level + "case (" + _printexpr(ns, node.test) + ")\n"
for case in node.cases:
r += "\t"*(level + 1) + _printexpr(ns, case[0]) + ": begin\n"
r += _printnode(ns, at, level + 2, case[1])
r += "\t"*(level + 1) + "end\n"
if node.default.l:
r += "\t"*(level + 1) + "default: begin\n"
r += _printnode(ns, at, level + 2, node.default)
r += "\t"*(level + 1) + "end\n"
r += "\t"*level + "endcase\n"
return r
else:
raise TypeError
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)
targets = list_targets(f)
instouts = list_inst_outs(f)
wires = _list_comb_wires(f)
r = "module " + name + "(\n"
firstp = True
for sig in ios:
if not firstp:
r += ",\n"
firstp = False
if sig in targets:
if sig in wires:
r += "\toutput " + _printsig(ns, sig)
else:
r += "\toutput reg " + _printsig(ns, sig)
elif sig in instouts:
r += "\toutput " + _printsig(ns, sig)
else:
r += "\tinput " + _printsig(ns, sig)
r += "\n);\n\n"
for sig in sigs - ios:
if sig in wires or sig in instouts:
r += "wire " + _printsig(ns, sig) + ";\n"
else:
r += "reg " + _printsig(ns, sig) + ";\n"
r += "\n"
return r
def _printcomb(f, ns):
r = ""
if f.comb.l:
# 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'b0;\n"
r += syn_on
groups = group_by_targets(f.comb)
for g in 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"
for t in g[0]:
r += "\t" + ns.get_name(t) + " <= " + str(t.reset) + ";\n"
r += _printnode(ns, _AT_NONBLOCKING, 1, _StatementList(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, clk_signal, rst_signal):
r = ""
if f.sync.l:
r += "always @(posedge " + ns.get_name(clk_signal) + ") begin\n"
r += _printnode(ns, _AT_SIGNAL, 1, insert_reset(rst_signal, f.sync))
r += "end\n\n"
return r
def _printinstances(ns, i, clk, rst):
r = ""
for x in i:
r += x.of + " "
if x.parameters:
r += "#(\n"
firstp = True
for p in x.parameters:
if not firstp:
r += ",\n"
firstp = False
r += "\t." + p[0] + "("
if isinstance(p[1], int) or isinstance(p[1], float) or isinstance(p[1], Constant):
r += str(p[1])
elif isinstance(p[1], str):
r += "\"" + p[1] + "\""
else:
raise TypeError
r += ")"
r += "\n) "
r += ns.get_name(x)
if x.parameters: r += " "
r += "(\n"
ports = list(x.ins.items()) + list(x.outs.items())
if x.clkport:
ports.append((x.clkport, clk))
if x.rstport:
ports.append((x.rstport, rst))
firstp = True
for p in ports:
if not firstp:
r += ",\n"
firstp = False
r += "\t." + p[0] + "(" + ns.get_name(p[1]) + ")"
if not firstp:
r += "\n"
r += ");\n\n"
return r
def convert(f, ios=set(), name="top", clk_signal=None, rst_signal=None, return_ns=False):
if clk_signal is None:
clk_signal = Signal(name_override="sys_clk")
ios.add(clk_signal)
if rst_signal is None:
rst_signal = Signal(name_override="sys_rst")
ios.add(rst_signal)
ns = Namespace(namer.build_pnd(list_signals(f)))
ios |= f.pads
r = "/* Machine-generated using Migen */\n"
r += _printheader(f, ios, name, ns)
r += _printcomb(f, ns)
r += _printsync(f, ns, clk_signal, rst_signal)
r += _printinstances(ns, f.instances, clk_signal, rst_signal)
r += "endmodule\n"
if return_ns:
return r, ns
else:
return r