src/add/pipeline_example.py

   1 """ Example 5: Making use of PyRTL and Introspection. """
   2
   3 from nmigen import Module, Signal, Const
   4 from nmigen.cli import main, verilog, rtlil
   5
   6
   7 from pipeline import SimplePipeline, ObjectProxy, PipeManager
   8
   9
  10 class SimplePipelineExample(SimplePipeline):
  11     """ A very simple pipeline to show how registers are inferred. """
  12
  13     def __init__(self, pipe):
  14         SimplePipeline.__init__(self, pipe)
  15         self._loopback = Signal(4)
  16         self._setup()
  17
  18     def stage0(self):
  19         self.n = ~self._loopback
  20
  21     def stage1(self):
  22         self.n = self.n + 2
  23
  24     def stage2(self):
  25         localv = Signal(4)
  26         self._pipe.comb += localv.eq(2)
  27         self.n = self.n << localv
  28
  29     def stage3(self):
  30         self.n = ~self.n
  31
  32     def stage4(self):
  33         self._pipe.sync += self._loopback.eq(self.n + 3)
  34
  35
  36 class ObjectBasedPipelineExample(SimplePipeline):
  37     """ A very simple pipeline to show how registers are inferred. """
  38
  39     def __init__(self, m):
  40         SimplePipeline.__init__(self, m)
  41         self._loopback = Signal(4)
  42         o = ObjectProxy(m)
  43         o.a = Signal(4)
  44         o.b = Signal(4)
  45         self._obj = o
  46         self._setup()
  47
  48     def stage0(self):
  49         self.n = ~self._loopback
  50         self.o = self._obj
  51
  52     def stage1(self):
  53         self.n = self.n + self.o.a
  54         o = ObjectProxy(self._m)
  55         o.a = self.n
  56         o.b = self.o.b + self.n + Const(5)
  57         self.o = o
  58
  59     def stage2(self):
  60         localv = Signal(4)
  61         self._m.d.comb += localv.eq(2)
  62         self.n = self.n << localv
  63         o = ObjectProxy(self._m)
  64         o.b = self.n + self.o.a + self.o.b
  65         self.o = o
  66
  67     def stage3(self):
  68         self.n = ~self.n
  69         self.o = self.o
  70         self.o.b = self.o.b + self.n
  71
  72     def stage4(self):
  73         self._m.d.sync += self._loopback.eq(self.n + 3 + self.o.b)
  74
  75
  76 class PipeModule:
  77
  78     def __init__(self):
  79         self.m = Module()
  80         self.p = ObjectBasedPipelineExample(self.m)
  81
  82     def get_fragment(self, platform=None):
  83         return self.m
  84
  85
  86 class PipelineStageExample:
  87
  88     def __init__(self):
  89         self._loopback = Signal(4)
  90
  91     def get_fragment(self, platform=None):
  92
  93         m = Module()
  94
  95         with PipeManager(m, pipemode=True) as pipe:
  96
  97             with pipe.Stage("first", ispec=[self._loopback]) as (p, m):
  98                 p.n = ~self._loopback
  99             with pipe.Stage("second", p) as (p, m):
 100                 #p.n = ~self._loopback + 2
 101                 p.n = p.n + 2
 102             with pipe.Stage("third", p) as (p, m):
 103                 #p.n = ~self._loopback + 5
 104                 localv = Signal(4)
 105                 m.d.comb += localv.eq(2)
 106                 p.n = p.n << localv + 1
 107                 #p.m = p.n + 2
 108
 109         print (pipe.stages)
 110
 111         return m
 112
 113 class PipelineStageObjectExample:
 114
 115     def __init__(self):
 116         self._loopback = Signal(4)
 117
 118     def get_fragment(self, platform=None):
 119
 120         m = Module()
 121
 122         o = ObjectProxy(m, pipemode=False)
 123         o.a = Signal(4)
 124         o.b = Signal(4)
 125         self.obj = o
 126
 127         localv2 = Signal(4)
 128         m.d.sync += localv2.eq(localv2 + 3)
 129
 130         #m.d.comb += self.obj.a.eq(localv2 + 1)
 131         #m.d.sync += self._loopback.eq(localv2)
 132
 133         with PipeManager(m, pipemode=True) as pipe:
 134
 135             with pipe.Stage("first",
 136                             ispec=[self._loopback, self.obj]) as (p, m):
 137                 p.n = ~self._loopback
 138                 p.o = self.obj
 139             with pipe.Stage("second", p) as (p, m):
 140                 #p.n = ~self._loopback + 2
 141                 p.n = p.n + Const(2)
 142                 o = ObjectProxy(m, pipemode=False)
 143                 o.a = p.n
 144                 o.b = p.o.b + p.n + Const(5)
 145                 p.o = o
 146             with pipe.Stage("third", p) as (p, m):
 147                 #p.n = ~self._loopback + 5
 148                 localv = Signal(4)
 149                 m.d.comb += localv.eq(2)
 150                 p.n = p.n << localv
 151                 o = ObjectProxy(m, pipemode=False)
 152                 o.b = p.n + p.o.b + p.o.a
 153                 p.o = o
 154
 155         print ("stages", pipe.stages)
 156
 157         return m
 158
 159
 160
 161 if __name__ == "__main__":
 162     example = PipeModule()
 163     with open("pipe_module.il", "w") as f:
 164         f.write(rtlil.convert(example, ports=[
 165                example.p._loopback,
 166              ]))
 167     example = PipelineStageExample()
 168     with open("pipe_stage_module.il", "w") as f:
 169         f.write(rtlil.convert(example, ports=[
 170                example._loopback,
 171              ]))
 172     example = PipelineStageObjectExample()
 173     with open("pipe_stage_object_module.il", "w") as f:
 174         f.write(rtlil.convert(example, ports=[
 175                example._loopback,
 176              ]))