From cd8544c7581d8df8f513ef4b920e79a4ef3ba8be Mon Sep 17 00:00:00 2001
From: Sebastien Bourdeauducq <sebastien@milkymist.org>
Date: Sun, 4 Dec 2011 22:26:32 +0100
Subject: [PATCH] Verilog generator

---
 migen/fhdl/structure.py |   5 +-
 migen/fhdl/verilog.py   | 137 ++++++++++++++++++++++++++++++++++++++++
 test.py                 |   4 +-
 3 files changed, 144 insertions(+), 2 deletions(-)
 create mode 100644 migen/fhdl/verilog.py

diff --git a/migen/fhdl/structure.py b/migen/fhdl/structure.py
index cdaf48c34..db37eee7f 100644
--- a/migen/fhdl/structure.py
+++ b/migen/fhdl/structure.py
@@ -146,6 +146,9 @@ class Signal(Value):
 
 	def __str__(self):
 		return self.name
+	
+	def __hash__(self):
+		return id(self)
 
 def Declare(parent, name, bv=BV(), variable=False, reset=0):
 	setattr(parent, name, Signal(bv, parent.__class__.__name__+"_"+name, variable, reset))
@@ -178,7 +181,7 @@ def _indent(s):
 		return "\t" + s.replace("\n", "\n\t")
 	else:
 		return ""
-
+		
 class If:
 	def __init__(self, cond, t, f=StatementList()):
 		self.cond = cond
diff --git a/migen/fhdl/verilog.py b/migen/fhdl/verilog.py
new file mode 100644
index 000000000..a3f02624a
--- /dev/null
+++ b/migen/fhdl/verilog.py
@@ -0,0 +1,137 @@
+from .structure import *
+from functools import partial
+
+class Namespace:
+	def __init__(self):
+		self.counts = {}
+		self.sigs = {}
+	
+	def GetName(self, sig):
+		try:
+			n = self.sigs[sig]
+			if n:
+				return sig.name + "_" + str(n)
+			else:
+				return sig.name
+		except KeyError:
+			try:
+				n = self.counts[sig.name]
+			except KeyError:
+				n = 0
+			self.sigs[sig] = n
+			self.counts[sig.name] = n + 1
+			if n:
+				return sig.name + "_" + str(n)
+			else:
+				return sig.name
+
+def ListSignals(node):
+	if isinstance(node, Constant):
+		return set()
+	elif isinstance(node, Signal):
+		return {node}
+	elif isinstance(node, Operator):
+		l = list(map(ListSignals, node.operands))
+		return set().union(*l)
+	elif isinstance(node, Slice):
+		return ListSignals(node.value)
+	elif isinstance(node, Cat):
+		l = list(map(ListSignals, node.l))
+		return set().union(*l)
+	elif isinstance(node, Assign):
+		return ListSignals(node.l) | ListSignals(node.r)
+	elif isinstance(node, StatementList):
+		l = list(map(ListSignals, node.l))
+		return set().union(*l)
+	elif isinstance(node, If):
+		return ListSignals(node.cond) | ListSignals(node.t) | ListSignals(node.f)
+	elif isinstance(node, Fragment):
+		return ListSignals(node.comb) | ListSignals(node.sync)
+	else:
+		raise TypeError
+
+def Convert(f, ins, outs, name="top"):
+	ns = Namespace()
+	
+	clks = Signal(name="sys_clk")
+	rsts = Signal(name="sys_rst")
+	clk = ns.GetName(clks)
+	rst = ns.GetName(rsts)
+	
+	def printsig(s):
+		if s.bv.signed:
+			n = "signed "
+		else:
+			n = ""
+		if s.bv.width > 1:
+			n += "[" + str(s.bv.width-1) + ":0] "
+		n += ns.GetName(s)
+		return n
+	
+	def printnode(level, node):
+		if isinstance(node, Constant):
+			return str(node)
+		elif isinstance(node, Signal):
+			return ns.GetName(node)
+		elif isinstance(node, Operator):
+			arity = len(node.operands)
+			if arity == 1:
+				r = self.op + str(node.operands[0])
+			elif arity == 2:
+				r = printnode(level, node.operands[0]) + " " + node.op + " " + printnode(level, 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 str(node.value) + sr
+		elif isinstance(node, Cat):
+			l = list(map(partial(printnode, level), node.l))
+			l.reverse()
+			return "{" + ", ".join(l) + "}"
+		elif isinstance(node, Assign):
+			# TODO: variables
+			return "\t"*level + printnode(level, node.l) + " <= " + printnode(level, node.r) + ";\n"
+		elif isinstance(node, StatementList):
+			return "".join(list(map(partial(printnode, level), node.l)))
+		elif isinstance(node, If):
+			r = "\t"*level + "if " + printnode(level, node.cond) + " begin\n"
+			r += printnode(level + 1, node.t)
+			if node.f.l:
+				r += "\t"*level + "end else begin\n"
+				r += printnode(level + 1, node.f)
+			r += "\t"*level + "end\n"
+			return r
+		else:
+			raise TypeError
+		
+	r = "/* Autogenerated by Migen */\n"
+	r += "module " + name + "(\n"
+	r += "\tinput " + clk + ",\n"
+	r += "\tinput " + rst
+	if ins:
+		r += ",\n\tinput " + ",\n\tinput ".join(map(printsig, ins)) 
+	if outs:
+		r += ",\n\toutput reg " + ",\n\toutput reg ".join(map(printsig, outs)) 
+	r += "\n);\n\n"
+	sigs = ListSignals(f).difference(ins, outs)
+	for sig in sigs:
+		r += "reg " + printsig(sig) + ";\n"
+	r += "\n"
+	
+	if f.comb.l:
+		r += "always @(*) begin\n"
+		r += printnode(1, f.comb)
+		r += "end\n\n"
+	
+	if f.sync.l:
+		r += "always @(posedge " + clk + ") begin\n"
+		r += printnode(1, f.sync)
+		r += "end\n\n"
+	
+	r += "endmodule\n"
+	
+	return r
\ No newline at end of file
diff --git a/test.py b/test.py
index 9a0f13609..0531ad42e 100644
--- a/test.py
+++ b/test.py
@@ -1,4 +1,5 @@
 from migen.fhdl import structure as f
+from migen.fhdl import verilog
 from functools import partial
 
 class Divider:
@@ -45,4 +46,5 @@ class Divider:
 
 d = Divider(32)
 f = d.GetFragment()
-print(f)
\ No newline at end of file
+o = verilog.Convert(f, {d.start_i, d.dividend_i, d.divisor_i}, {d.ready_o, d.quotient_o, d.remainder_o})
+print(o)
\ No newline at end of file