From: Luke Kenneth Casson Leighton <lkcl@lkcl.net>
Date: Fri, 15 Mar 2019 08:28:18 +0000 (+0000)
Subject: create classes for STB/BUSY, split in from out
X-Git-Tag: ls180-24jan2020~1661
X-Git-Url: https://git.libre-soc.org/?p=ieee754fpu.git;a=commitdiff_plain;h=0bfbc8ff919f0cd9c7f01b4c711b1b91a53ad480

create classes for STB/BUSY, split in from out
---

diff --git a/src/add/example_buf_pipe.py b/src/add/example_buf_pipe.py
index 6678a671..37f866c3 100644
--- a/src/add/example_buf_pipe.py
+++ b/src/add/example_buf_pipe.py
@@ -12,12 +12,12 @@
     where data will flow on *every* clock when the conditions are right.
 
     input acceptance conditions are when:
-        * incoming previous-stage strobe (i_p_stb) is HIGH
-        * outgoing previous-stage busy   (o_p_busy) is LOW
+        * incoming previous-stage strobe (i.p_stb) is HIGH
+        * outgoing previous-stage busy   (o.p_busy) is LOW
 
     output transmission conditions are when:
-        * outgoing next-stage strobe (o_n_stb) is HIGH
-        * outgoing next-stage busy   (i_n_busy) is LOW
+        * outgoing next-stage strobe (o.n_stb) is HIGH
+        * outgoing next-stage busy   (i.n_busy) is LOW
 
     the tricky bit is when the input has valid data and the output is not
     ready to accept it.  if it wasn't for the clock synchronisation, it
@@ -100,12 +100,25 @@ class ExampleStage:
     def ports(self):
         return [self.i_data, self.o_data]
 
+class IOAckIn:
+
+    def __init__(self):
+        self.p_stb = Signal()  # >>in - comes in from PREVIOUS stage
+        self.n_busy = Signal() # in<< - comes in from the NEXT stage
+
+
+class IOAckOut:
+
+    def __init__(self):
+        self.n_stb = Signal()  # out>> - goes out to the NEXT stage
+        self.p_busy = Signal() # <<out - goes out to the PREVIOUS stage
+
 
 class BufferedPipeline:
     """ buffered pipeline stage
 
-        stage-1   i_p_stb  >>in   stage   o_n_stb  out>>   stage+1
-        stage-1   o_p_busy <<out  stage   i_n_busy <<in    stage+1
+        stage-1   i.p_stb  >>in   stage   o.n_stb  out>>   stage+1
+        stage-1   o.p_busy <<out  stage   i.n_busy <<in    stage+1
         stage-1   i_data   >>in   stage   o_data   out>>   stage+1
                               |             |
                               +------->  process
@@ -114,13 +127,14 @@ class BufferedPipeline:
     """
     def __init__(self):
         # input: strobe comes in from previous stage, busy comes in from next
-        #self.i_p_rst = Signal()    # >>in - comes in from PREVIOUS stage
-        self.i_p_stb = Signal()    # >>in - comes in from PREVIOUS stage
-        self.i_n_busy = Signal()   # in<< - comes in from the NEXT stage
+        self.i = IOAckIn()
+        #self.i.p_stb = Signal()    # >>in - comes in from PREVIOUS stage
+        #self.i.n_busy = Signal()   # in<< - comes in from the NEXT stage
 
         # output: strobe goes out to next stage, busy comes in from previous
-        self.o_n_stb = Signal()    # out>> - goes out to the NEXT stage
-        self.o_p_busy = Signal()   # <<out - goes out to the PREVIOUS stage
+        self.o = IOAckOut()
+        #self.o.n_stb = Signal()    # out>> - goes out to the NEXT stage
+        #self.o.p_busy = Signal()   # <<out - goes out to the PREVIOUS stage
 
     def elaborate(self, platform):
         m = Module()
@@ -130,54 +144,54 @@ class BufferedPipeline:
         o_n_stbn = Signal(reset_less=True)
         i_n_busyn = Signal(reset_less=True)
         i_p_stb_o_p_busyn = Signal(reset_less=True)
-        m.d.comb += [i_n_busyn.eq(~self.i_n_busy),
-                     o_n_stbn.eq(~self.o_n_stb),
-                     o_p_busyn.eq(~self.o_p_busy),
-                     i_p_stb_o_p_busyn.eq(self.i_p_stb & o_p_busyn),
+        m.d.comb += [i_n_busyn.eq(~self.i.n_busy),
+                     o_n_stbn.eq(~self.o.n_stb),
+                     o_p_busyn.eq(~self.o.p_busy),
+                     i_p_stb_o_p_busyn.eq(self.i.p_stb & o_p_busyn),
         ]
 
         # store result of processing in combinatorial temporary
-        with m.If(self.i_p_stb): # input is valid: process it
+        with m.If(self.i.p_stb): # input is valid: process it
             m.d.comb += self.stage.process()
         # if not in stall condition, update the temporary register
         with m.If(o_p_busyn): # not stalled
             m.d.sync += self.stage.update_buffer()
 
-        #with m.If(self.i_p_rst): # reset
-        #    m.d.sync += self.o_n_stb.eq(0)
-        #    m.d.sync += self.o_p_busy.eq(0)
+        #with m.If(self.i.p_rst): # reset
+        #    m.d.sync += self.o.n_stb.eq(0)
+        #    m.d.sync += self.o.p_busy.eq(0)
         with m.If(i_n_busyn): # next stage is not busy
             with m.If(o_p_busyn): # not stalled
                 # nothing in buffer: send (processed) input direct to output
-                m.d.sync += [self.o_n_stb.eq(self.i_p_stb),
+                m.d.sync += [self.o.n_stb.eq(self.i.p_stb),
                              self.stage.update_output(),
                             ]
-            with m.Else(): # o_p_busy is true, and something is in our buffer.
+            with m.Else(): # o.p_busy is true, and something is in our buffer.
                 # Flush the [already processed] buffer to the output port.
-                m.d.sync += [self.o_n_stb.eq(1),
+                m.d.sync += [self.o.n_stb.eq(1),
                              self.stage.flush_buffer(),
                              # clear stall condition, declare register empty.
-                             self.o_p_busy.eq(0),
+                             self.o.p_busy.eq(0),
                             ]
-                # ignore input, since o_p_busy is also true.
+                # ignore input, since o.p_busy is also true.
 
-        # (i_n_busy) is true here: next stage is busy
+        # (i.n_busy) is true here: next stage is busy
         with m.Elif(o_n_stbn): # next stage being told "not busy"
-            m.d.sync += [self.o_n_stb.eq(self.i_p_stb),
-                         self.o_p_busy.eq(0), # Keep the buffer empty
+            m.d.sync += [self.o.n_stb.eq(self.i.p_stb),
+                         self.o.p_busy.eq(0), # Keep the buffer empty
                          # set the output data (from comb result)
                          self.stage.update_output(),
                         ]
-        # (i_n_busy) and (o_n_stb) both true:
+        # (i.n_busy) and (o.n_stb) both true:
         with m.Elif(i_p_stb_o_p_busyn):
             # If next stage *is* busy, and not stalled yet, accept input
-            m.d.sync += self.o_p_busy.eq(self.i_p_stb & self.o_n_stb)
+            m.d.sync += self.o.p_busy.eq(self.i.p_stb & self.o.n_stb)
 
         return m
 
     def ports(self):
-        return [self.i_p_stb, self.i_n_busy,
-                self.o_n_stb, self.o_p_busy,
+        return [self.i.p_stb, self.i.n_busy,
+                self.o.n_stb, self.o.p_busy,
                ]
 
 
diff --git a/src/add/test_buf_pipe.py b/src/add/test_buf_pipe.py
index 8590ccad..baa344a9 100644
--- a/src/add/test_buf_pipe.py
+++ b/src/add/test_buf_pipe.py
@@ -5,20 +5,24 @@ from random import randint
 
 
 def check_o_n_stb(dut, val):
+    o_n_stb = yield dut.o.n_stb
+    assert o_n_stb == val
+
+def check_o_n_stb2(dut, val):
     o_n_stb = yield dut.o_n_stb
     assert o_n_stb == val
 
 
 def testbench(dut):
     #yield dut.i_p_rst.eq(1)
-    yield dut.i_n_busy.eq(1)
-    yield dut.o_p_busy.eq(1)
+    yield dut.i.n_busy.eq(1)
+    yield dut.o.p_busy.eq(1)
     yield
     yield
     #yield dut.i_p_rst.eq(0)
-    yield dut.i_n_busy.eq(0)
+    yield dut.i.n_busy.eq(0)
     yield dut.stage.i_data.eq(5)
-    yield dut.i_p_stb.eq(1)
+    yield dut.i.p_stb.eq(1)
     yield
 
     yield dut.stage.i_data.eq(7)
@@ -28,14 +32,14 @@ def testbench(dut):
 
     yield dut.stage.i_data.eq(2)
     yield
-    yield dut.i_n_busy.eq(1) # begin going into "stall" (next stage says busy)
+    yield dut.i.n_busy.eq(1) # begin going into "stall" (next stage says busy)
     yield dut.stage.i_data.eq(9)
     yield
-    yield dut.i_p_stb.eq(0)
+    yield dut.i.p_stb.eq(0)
     yield dut.stage.i_data.eq(12)
     yield
     yield dut.stage.i_data.eq(32)
-    yield dut.i_n_busy.eq(0)
+    yield dut.i.n_busy.eq(0)
     yield
     yield from check_o_n_stb(dut, 1) # buffer still needs to output
     yield
@@ -46,25 +50,25 @@ def testbench(dut):
 
 
 def testbench2(dut):
-    #yield dut.i_p_rst.eq(1)
+    #yield dut.i.p_rst.eq(1)
     yield dut.i_n_busy.eq(1)
-    #yield dut.o_p_busy.eq(1)
+    #yield dut.o.p_busy.eq(1)
     yield
     yield
-    #yield dut.i_p_rst.eq(0)
+    #yield dut.i.p_rst.eq(0)
     yield dut.i_n_busy.eq(0)
     yield dut.i_data.eq(5)
     yield dut.i_p_stb.eq(1)
     yield
 
     yield dut.i_data.eq(7)
-    yield from check_o_n_stb(dut, 0) # effects of i_p_stb delayed 2 clocks
+    yield from check_o_n_stb2(dut, 0) # effects of i_p_stb delayed 2 clocks
     yield
-    yield from check_o_n_stb(dut, 0) # effects of i_p_stb delayed 2 clocks
+    yield from check_o_n_stb2(dut, 0) # effects of i_p_stb delayed 2 clocks
 
     yield dut.i_data.eq(2)
     yield
-    yield from check_o_n_stb(dut, 1) # ok *now* i_p_stb effect is felt
+    yield from check_o_n_stb2(dut, 1) # ok *now* i_p_stb effect is felt
     yield dut.i_n_busy.eq(1) # begin going into "stall" (next stage says busy)
     yield dut.i_data.eq(9)
     yield
@@ -74,13 +78,13 @@ def testbench2(dut):
     yield dut.i_data.eq(32)
     yield dut.i_n_busy.eq(0)
     yield
-    yield from check_o_n_stb(dut, 1) # buffer still needs to output
+    yield from check_o_n_stb2(dut, 1) # buffer still needs to output
     yield
-    yield from check_o_n_stb(dut, 1) # buffer still needs to output
+    yield from check_o_n_stb2(dut, 1) # buffer still needs to output
     yield
-    yield from check_o_n_stb(dut, 1) # buffer still needs to output
+    yield from check_o_n_stb2(dut, 1) # buffer still needs to output
     yield
-    yield from check_o_n_stb(dut, 0) # buffer outputted, *now* we're done.
+    yield from check_o_n_stb2(dut, 0) # buffer outputted, *now* we're done.
     yield
     yield
     yield
@@ -104,16 +108,16 @@ class Test3:
                     send = True
                 else:
                     send = randint(0, send_range) != 0
-                o_p_busy = yield self.dut.o_p_busy
+                o_p_busy = yield self.dut.o.p_busy
                 if o_p_busy:
                     yield
                     continue
                 if send and self.i != len(self.data):
-                    yield self.dut.i_p_stb.eq(1)
+                    yield self.dut.i.p_stb.eq(1)
                     yield self.dut.stage.i_data.eq(self.data[self.i])
                     self.i += 1
                 else:
-                    yield self.dut.i_p_stb.eq(0)
+                    yield self.dut.i.p_stb.eq(0)
                 yield
 
     def rcv(self):
@@ -121,10 +125,10 @@ class Test3:
             stall_range = randint(0, 3)
             for j in range(randint(1,10)):
                 stall = randint(0, stall_range) == 0
-                yield self.dut.i_n_busy.eq(stall)
+                yield self.dut.i.n_busy.eq(stall)
                 yield
-                o_n_stb = yield self.dut.o_n_stb
-                i_n_busy = yield self.dut.i_n_busy
+                o_n_stb = yield self.dut.o.n_stb
+                i_n_busy = yield self.dut.i.n_busy
                 if not o_n_stb or i_n_busy:
                     continue
                 o_data = yield self.dut.stage.o_data
@@ -195,18 +199,18 @@ class BufPipe2:
         m.submodules.pipe2 = self.pipe2
 
         # connect inter-pipe input/output stb/busy/data
-        m.d.comb += self.pipe2.i_p_stb.eq(self.pipe1.o_n_stb)
-        m.d.comb += self.pipe1.i_n_busy.eq(self.pipe2.o_p_busy)
+        m.d.comb += self.pipe2.i.p_stb.eq(self.pipe1.o.n_stb)
+        m.d.comb += self.pipe1.i.n_busy.eq(self.pipe2.o.p_busy)
         m.d.comb += self.pipe2.stage.i_data.eq(self.pipe1.stage.o_data)
 
         # inputs/outputs to the module: pipe1 connections here (LHS)
-        m.d.comb += self.pipe1.i_p_stb.eq(self.i_p_stb)
-        m.d.comb += self.o_p_busy.eq(self.pipe1.o_p_busy)
+        m.d.comb += self.pipe1.i.p_stb.eq(self.i_p_stb)
+        m.d.comb += self.o_p_busy.eq(self.pipe1.o.p_busy)
         m.d.comb += self.pipe1.stage.i_data.eq(self.i_data)
 
         # now pipe2 connections (RHS)
-        m.d.comb += self.o_n_stb.eq(self.pipe2.o_n_stb)
-        m.d.comb += self.pipe2.i_n_busy.eq(self.i_n_busy)
+        m.d.comb += self.o_n_stb.eq(self.pipe2.o.n_stb)
+        m.d.comb += self.pipe2.i.n_busy.eq(self.i_n_busy)
         m.d.comb += self.o_data.eq(self.pipe2.stage.o_data)
 
         return m