From: Sebastien Bourdeauducq <sebastien@milkymist.org>
Date: Fri, 27 Jan 2012 19:22:17 +0000 (+0100)
Subject: fhdl: memories working
X-Git-Tag: 24jan2021_ls180~2099^2~1052
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=5405a83ff9068d0921fc8820cf01bbaefd43a4d5;p=litex.git

fhdl: memories working
---

diff --git a/examples/memory.py b/examples/memory.py
new file mode 100644
index 00000000..e8f4531e
--- /dev/null
+++ b/examples/memory.py
@@ -0,0 +1,21 @@
+from migen.fhdl.structure import *
+from migen.fhdl import verilog
+
+d = 100
+d_b = bits_for(d-1)
+w = 32
+
+a1 = Signal(BV(d_b))
+d1 = Signal(BV(w))
+we1 = Signal(BV(4))
+dw1 = Signal(BV(w))
+p1 = MemoryPort(a1, d1, we1, dw1, we_granularity=8, mode=WRITE_FIRST)
+
+a2 = Signal(BV(d_b))
+d2 = Signal(BV(w))
+p2 = MemoryPort(a2, d2)
+
+mem = Memory(w, d, p1, p2, init=[5, 18, 32])
+f = Fragment(memories=[mem])
+v = verilog.convert(f, ios={a1, d1, we1, dw1, a2, d2})
+print(v)
diff --git a/migen/fhdl/structure.py b/migen/fhdl/structure.py
index b52f4539..c953834d 100644
--- a/migen/fhdl/structure.py
+++ b/migen/fhdl/structure.py
@@ -228,8 +228,11 @@ class Instance:
 	def __hash__(self):
 		return id(self)
 
+(READ_FIRST, WRITE_FIRST, NO_CHANGE) = range(3)
+
 class MemoryPort:
-	def __init__(self, adr, dat_r, we=None, dat_w=None, async_read=False, re=None, we_granularity=0):
+	def __init__(self, adr, dat_r, we=None, dat_w=None,
+	  async_read=False, re=None, we_granularity=0, mode=READ_FIRST):
 		self.adr = adr
 		self.dat_r = dat_r
 		self.we = we
@@ -237,6 +240,7 @@ class MemoryPort:
 		self.async_read = async_read
 		self.re = re
 		self.we_granularity = we_granularity
+		self.mode = mode
 
 class Memory:
 	def __init__(self, width, depth, *ports, init=None):
diff --git a/migen/fhdl/verilog.py b/migen/fhdl/verilog.py
index 4c7bc434..f169b508 100644
--- a/migen/fhdl/verilog.py
+++ b/migen/fhdl/verilog.py
@@ -205,10 +205,10 @@ def _printinstances(f, ns, clk, rst):
 		r += ");\n\n"
 	return r
 
-def _printmemories(f, ns, handler, clk, rst):
+def _printmemories(f, ns, handler, clk):
 	r = ""
 	for memory in f.memories:
-		r += handler(memory, ns, clk, rst)
+		r += handler(memory, ns, clk)
 	return r
 
 def convert(f, ios=set(), name="top",
@@ -233,7 +233,7 @@ def convert(f, ios=set(), name="top",
 	r += _printcomb(f, ns)
 	r += _printsync(f, ns, clk_signal, rst_signal)
 	r += _printinstances(f, ns, clk_signal, rst_signal)
-	r += _printmemories(f, ns, memory_handler, clk_signal, rst_signal)
+	r += _printmemories(f, ns, memory_handler, clk_signal)
 	r += "endmodule\n"
 
 	if return_ns:
diff --git a/migen/fhdl/verilog_mem_behavioral.py b/migen/fhdl/verilog_mem_behavioral.py
index 1a820672..31dddfa2 100644
--- a/migen/fhdl/verilog_mem_behavioral.py
+++ b/migen/fhdl/verilog_mem_behavioral.py
@@ -1,2 +1,70 @@
-def handler(memory, ns, clk, rst):
-	return "/* TODO: implement memory */\n"
+from migen.fhdl.structure import *
+
+def handler(memory, ns, clk):
+	r = ""
+	gn = ns.get_name
+	adrbits = bits_for(memory.depth-1)
+	
+	storage = Signal(name_override="mem")
+	r += "reg [" + str(memory.width-1) + ":0] " \
+		+ gn(storage) \
+		+ "[0:" + str(memory.depth-1) + "];\n"
+
+	adr_regs = {}
+	data_regs = {}
+	for port in memory.ports:
+		if not port.async_read:
+			if port.mode == WRITE_FIRST and port.we is not None:
+				adr_reg = Signal(name_override="memadr")
+				r += "reg [" + str(adrbits-1) + ":0] " \
+					+ gn(adr_reg) + ";\n"
+				adr_regs[id(port)] = adr_reg
+			else:
+				data_reg = Signal(name_override="memdat")
+				r += "reg [" + str(memory.width-1) + ":0] " \
+					+ gn(data_reg) + ";\n"
+				data_regs[id(port)] = data_reg
+
+	r += "always @(posedge " + gn(clk) + ") begin\n"
+	for port in memory.ports:
+		if port.we is not None:
+			if port.we_granularity:
+				n = memory.width//port.we_granularity
+				for i in range(n):
+					m = i*port.we_granularity
+					M = (i+1)*port.we_granularity-1
+					sl = "[" + str(M) + ":" + str(m) + "]"
+					r += "\tif (" + gn(port.we) + "[" + str(i) + "])\n"
+					r += "\t\t" + gn(storage) + "[" + gn(port.adr) + "]" + sl + " <= " + gn(port.dat_w) + sl + ";\n"
+			else:
+				r += "\tif (" + gn(port.we) + ")\n"
+				r += "\t\t" + gn(storage) + "[" + gn(port.adr) + "] <= " + gn(port.dat_w) + ";\n"
+		if not port.async_read:
+			if port.mode == WRITE_FIRST and port.we is not None:
+				r += "\t" + gn(adr_regs[id(port)]) + " <= " + gn(port.adr) + ";\n"
+			else:
+				bassign = gn(data_regs[id(port)]) + " <= " + gn(storage) + "[" + gn(port.adr) + "];\n"
+				if port.mode == READ_FIRST or port.we is None:
+					r += "\t" + bassign
+				elif port.mode == NO_CHANGE:
+					r += "\tif (!" + gn(port.we) + ")\n"
+					r += "\t\t" + bassign
+	r += "end\n\n"
+	
+	for port in memory.ports:
+		if port.async_read:
+			r += "assign " + gn(port.dat_r) + " = " + gn(storage) + "[" + gn(port.adr) + "];\n"
+		else:
+			if port.mode == WRITE_FIRST and port.we is not None:
+				r += "assign " + gn(port.dat_r) + " = " + gn(storage) + "[" + gn(adr_regs[id(port)]) + "];\n"
+			else:
+				r += "assign " + gn(port.dat_r) + " = " + gn(data_regs[id(port)]) + ";\n"
+	r += "\n"
+	
+	if memory.init is not None:
+		r += "initial begin\n"
+		for i, c in enumerate(memory.init):
+			r += "\t" + gn(storage) + "[" + str(i) + "] <= " + str(memory.width) + "'d" + str(c) + ";\n"
+		r += "end\n\n"
+	
+	return r