Initial import, FHDL basic structure, divider example

.gitignore

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+__pycache__
+*.pyc

migen/fhdl/structure.py

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+import math
+
+def BitsFor(n):
+	if n == 0:
+		return 1
+	else:
+		return int(math.ceil(math.log(n+1, 2)))
+
+class BV:
+	def __init__(self, width=1, signed=False):
+		self.width = width
+		self.signed = signed
+	
+	def __str__(self):
+		r = str(self.width) + "'"
+		if self.signed:
+			r += "s"
+		r += "d"
+		return r
+
+class Value:
+	def __init__(self, bv):
+		self.bv = bv
+	
+	def __add__(self, other):
+		return Operator("+", [self, other])
+	def __radd__(self, other):
+		return Operator("+", [other, self])
+	def __sub__(self, other):
+		return Operator("-", [self, other])
+	def __rsub__(self, other):
+		return Operator("-", [other, self])
+	def __mul__(self, other):
+		return Operator("*", [self, other])
+	def __rmul__(self, other):
+		return Operator("*", [other, self])
+	def __lshift__(self, other):
+		return Operator("<<", [self, other])
+	def __rlshift__(self, other):
+		return Operator("<<", [other, self])
+	def __rshift__(self, other):
+		return Operator(">>", [self, other])
+	def __rrshift__(self, other):
+		return Operator(">>", [other, self])
+	def __and__(self, other):
+		return Operator("&", [self, other])
+	def __rand__(self, other):
+		return Operator("&", [other, self])
+	def __xor__(self, other):
+		return Operator("^", [self, other])
+	def __rxor__(self, other):
+		return Operator("^", [other, self])
+	def __or__(self, other):
+		return Operator("|", [self, other])
+	def __ror__(self, other):
+		return Operator("|", [other, self])
+	
+	def __lt__(self, other):
+		return Operator("<", [self, other])
+	def __le__(self, other):
+		return Operator("<=", [self, other])
+	def __eq__(self, other):
+		return Operator("==", [self, other])
+	def __ne__(self, other):
+		return Operator("!=", [self, other])
+	def __gt__(self, other):
+		return Operator(">", [self, other])
+	def __ge__(self, other):
+		return Operator(">=", [self, other])
+	
+	
+	def __getitem__(self, key):
+		if isinstance(key, int):
+			return Slice(self, key, key+1)
+		elif isinstance(key, slice):
+			start = key.start or 0
+			stop = key.stop or self.bv.width
+			if key.step != None:
+				raise KeyError
+			return Slice(self, start, stop)
+		else:
+			raise KeyError
+
+class Operator(Value):
+	def __init__(self, op, operands):
+		self.op = op
+		self.operands = list(map(_cst, operands))
+	
+	def __str__(self):
+		arity = len(self.operands)
+		if arity == 1:
+			r = self.op + str(self.operands[0])
+		elif arity == 2:
+			r = str(self.operands[0]) + " " + self.op + " " + str(self.operands[1])
+		else:
+			r = self.op + "(" + ", ".join(map(str, self.operands)) + ")"
+		return "(" + r + ")"
+
+class Slice(Value):
+	def __init__(self, value, start, stop):
+		self.value = value
+		self.start = start
+		self.stop = stop
+	
+	def __str__(self):
+		if self.start + 1 == self.stop:
+			sr = "[" + str(self.start) + "]"
+		else:
+			sr = "[" + str(self.start) + ":" + str(self.stop) + "]"
+		return str(self.value) + sr
+
+class Cat(Value):
+	def __init__(self, *args):
+		self.l = list(map(_cst, args))
+	
+	def __str__(self):
+		return "{" + ", ".join(map(str, self.l)) + "}"
+
+class Constant(Value):
+	def __init__(self, n, bv=None):
+		if bv == None:
+			Value.__init__(self, BV(BitsFor(n)))
+		else:
+			Value.__init__(self, bv)
+		self.n = n
+	
+	def __str__(self):
+		if self.n >= 0:
+			return str(self.bv) + str(self.n)
+		else:
+			return "-" + str(self.bv) + str(-self.n)
+
+def _cst(x):
+	if isinstance(x, int):
+		return Constant(x)
+	else:
+		return x
+
+class Signal(Value):
+	def __init__(self, bv=BV(), name="anonymous", variable=False, reset=0):
+		Value.__init__(self, bv)
+		self.bv = bv
+		self.variable = variable
+		self.name = name
+		self.reset = Constant(reset, bv)
+
+	def __str__(self):
+		return self.name
+
+def Declare(parent, name, bv=BV(), variable=False, reset=0):
+	setattr(parent, name, Signal(bv, parent.__class__.__name__+"_"+name, variable, reset))
+
+# statements
+
+class Assign:
+	def __init__(self, l, r):
+		self.l = l
+		self.r = _cst(r)
+	
+	def __str__(self):
+		return str(self.l) + " = " + str(self.r)
+
+class StatementList:
+	def __init__(self, l=[]):
+		self.l = l
+	
+	def __str__(self):
+		return "\n".join(map(str, self.l))
+
+def _sl(x):
+	if isinstance(x, list):
+		return StatementList(x)
+	else:
+		return x
+
+def _indent(s):
+	if s:
+		return "\t" + s.replace("\n", "\n\t")
+	else:
+		return ""
+
+class If:
+	def __init__(self, cond, t, f=StatementList()):
+		self.cond = cond
+		self.t = _sl(t)
+		self.f = _sl(f)
+	
+	def __str__(self):
+		r = "if " + str(self.cond) + ":\n" + _indent(str(self.t))
+		if self.f.l:
+			r += "\nelse:\n" + _indent(str(self.f))
+		return r
+
+class Case:
+	def __init__(self, test, cases=[]):
+		self.test = test
+		self.cases = cases
+
+#
+
+class Fragment:
+	def __init__(self, comb=StatementList(), sync=StatementList()):
+		self.comb = _sl(comb)
+		self.sync = _sl(sync)
+	
+	def __str__(self):
+		return "Comb:\n" + _indent(str(self.comb)) + "\nSync:\n" + _indent(str(self.sync))

test.py

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+from migen.fhdl import structure as f
+from functools import partial
+
+class Divider:
+	def __init__(self, w):
+		self.w = w
+		
+		d = partial(f.Declare, self)
+		
+		d("start_i")
+		d("dividend_i", f.BV(w))
+		d("divisor_i", f.BV(w))
+		d("ready_o")
+		d("quotient_o", f.BV(w))
+		d("remainder_o", f.BV(w))
+		
+		d("_qr", f.BV(2*w))
+		d("_counter", f.BV(f.BitsFor(w)))
+		d("_divisor_r", f.BV(w))
+		d("_diff", f.BV(w+1))
+	
+	def GetFragment(self):
+		a = f.Assign
+		comb = [
+			a(self.quotient_o, self._qr[:self.w]),
+			a(self.remainder_o, self._qr[self.w:]),
+			a(self.ready_o, self._counter == f.Constant(0, self._counter.bv)),
+			a(self._diff, self.remainder_o - self._divisor_r)
+		]
+		sync = [
+			f.If(self.start_i == 1, [
+				a(self._counter, self.w),
+				a(self._qr, self.dividend_i),
+				a(self._divisor_r, self.divisor_i)
+			], [
+				f.If(self.ready_o == 0, [
+					f.If(self._diff[self.w] == 1,
+						[a(self._qr, f.Cat(0, self._qr[:2*self.w-1]))],
+						[a(self._qr, f.Cat(1, self._qr[:self.w-1], self._diff[:self.w]))]),
+					a(self._counter, self._counter - f.Constant(1, self._counter.bv)),
+				])
+			])
+		]
+		return f.Fragment(comb, sync)
+
+d = Divider(32)
+f = d.GetFragment()
+print(f)