From 5b20bf3470388e97854b569822be5801e07cd291 Mon Sep 17 00:00:00 2001
From: jand <none@none>
Date: Thu, 6 Mar 2003 19:10:15 +0000
Subject: [PATCH] added

---
 example/manual/fifo.py         | 127 +++++++++++++++++++++++++++++++++
 example/manual/sparseMemory.py |  32 +++++++--
 2 files changed, 154 insertions(+), 5 deletions(-)
 create mode 100644 example/manual/fifo.py

diff --git a/example/manual/fifo.py b/example/manual/fifo.py
new file mode 100644
index 00000000..ba68f552
--- /dev/null
+++ b/example/manual/fifo.py
@@ -0,0 +1,127 @@
+from __future__ import generators
+import sys
+
+from myhdl import Signal, Simulation, posedge, negedge, delay, \
+                  StopSimulation, join
+
+class Error(Exception):
+    pass
+
+def fifo(dout, din, re, we, empty, full, clk, maxFilling=sys.maxint):
+    
+    """ Synchronous fifo model based on a list.
+    
+    Ports:
+    dout -- data out
+    din -- data in
+    re -- read enable
+    we -- write enable
+    empty -- empty indication flag
+    full -- full indication flag
+    clk -- clock input
+
+    Optional parameter:
+    maxFilling -- maximum fifo filling, "infinite" by default
+
+    """
+    
+    memory = []
+    while 1:
+        yield posedge(clk)
+        if we:
+            memory.insert(0, din.val)
+        if re:
+            dout.next = memory.pop()
+        empty.next = (len(memory) == 0)
+        full.next = (len(memory) == maxFilling)
+
+        
+def fifo2(dout, din, re, we, empty, full, clk, maxFilling=sys.maxint):
+    
+    """ Synchronous fifo model based on a list.
+
+    Ports:
+    dout -- data out
+    din -- data in
+    re -- read enable
+    we -- write enable
+    empty -- empty indication flag
+    full -- full indication flag
+    clk -- clock input
+    
+    Optional parameter:
+    maxFilling -- maximum fifo filling, "infinite" by default
+
+    """
+    
+    memory = []
+    while 1:
+        yield posedge(clk)
+        if we:
+            memory.insert(0, din.val)
+        if re:
+            try:
+                dout.next = memory.pop()
+            except IndexError:
+                raise Error, "Underflow - Read from empty fifo"
+        empty.next = (len(memory) == 0)
+        full.next = (len(memory) == maxFilling)
+        if len(memory) > maxFilling:
+            raise Error, "Overflow - Max filling %s exceeded" % maxFilling
+
+
+dout, din, re, we, empty, full, clk = args = [Signal(0) for i in range(7)]
+
+dut = fifo2(dout, din, re, we, empty, full, clk, maxFilling=3)
+
+def clkGen():
+    while 1:
+        yield delay(10)
+        clk.next = not clk
+
+def read():
+    yield negedge(clk)
+    re.next = 1
+    yield posedge(clk)
+    yield delay(1)
+    re.next = 0
+
+def write(data):
+    yield negedge(clk)
+    din.next = data
+    we.next = 1
+    yield posedge(clk)
+    yield delay(1)
+    we.next = 0
+
+def report():
+    print "dout: %s empty: %s full: %s" % (hex(dout), empty, full)
+    
+def test():
+    yield write(0x55)
+    report()
+    yield write(0x77)
+    report()
+    yield write(0x11)
+    report()
+    yield join(write(0x22), read())
+    report()
+    yield join(write(0x33), read())
+    report()
+    yield read()
+    report()
+    yield read()
+    report()
+    yield read()
+    report()
+    yield read()
+    report()
+    yield read()
+    raise StopSimulation
+
+    
+sim = Simulation(clkGen(), test(), dut)
+    
+if __name__ == "__main__":
+    sim.run()
+    
diff --git a/example/manual/sparseMemory.py b/example/manual/sparseMemory.py
index a54e450c..89467a5e 100644
--- a/example/manual/sparseMemory.py
+++ b/example/manual/sparseMemory.py
@@ -7,6 +7,31 @@ class Error(Exception):
     pass
 
 def sparseMemory(dout, din, addr, we, en, clk):
+    
+    """ Sparse memory model based on a dictionary.
+
+    Ports:
+    dout -- data out
+    din -- data in
+    addr -- address bus
+    we -- write enable: write if 1, read otherwise
+    en -- interface enable: enabled if 1
+    clk -- clock input
+    
+    """
+    memory = {}
+    while 1:
+        yield posedge(clk)
+        if not en:
+            continue
+        if we:
+            memory[addr] = din.val
+        else:
+            dout.next = memory[addr]
+            
+        
+def sparseMemory2(dout, din, addr, we, en, clk):
+    
     """ Sparse memory model based on a dictionary.
 
     Ports:
@@ -18,7 +43,6 @@ def sparseMemory(dout, din, addr, we, en, clk):
     clk -- clock input
     
     """
-    
     memory = {}
     while 1:
         yield posedge(clk)
@@ -27,17 +51,15 @@ def sparseMemory(dout, din, addr, we, en, clk):
         if we:
             memory[addr] = din.val
         else:
-            # dout.next = memory[addr]
             try:
                 dout.next = memory[addr]
             except KeyError:
                 raise Error, "Unitialized address %s" % hex(addr)
-        # print memory 
 
 
 dout, din, addr, we, en, clk = args = [Signal(0) for i in range(6)]
 
-dut = sparseMemory(*args)
+dut = sparseMemory2(*args)
 
 def clkGen():
     while 1:
@@ -71,7 +93,7 @@ def test():
     yield read(0x77)
     print hex(dout)
     yield read(0x55)
-    print hex(din)
+    print hex(dout)
     yield read(0x33)