src/add/pipeline_example.py

   1 """ Example 5: Making use of PyRTL and Introspection. """
   2
   3 from nmigen import Module, Signal
   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
  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
 107
 108         print (pipe.stages)
 109
 110         return m
 111
 112 class PipelineStageObjectExample:
 113
 114     def __init__(self):
 115         self._loopback = Signal(4)
 116
 117     def get_fragment(self, platform=None):
 118
 119         m = Module()
 120
 121         o = ObjectProxy(None)
 122         o.a = Signal(4)
 123         o.b = Signal(4)
 124         self._obj = o
 125
 126         with PipeManager(m, pipemode=True) as pipe:
 127
 128             with pipe.Stage("first",
 129                             ispec=[self._loopback, self._obj]) as (p, m):
 130                 p.n = ~self._loopback
 131                 p.o = self._obj
 132             with pipe.Stage("second", p) as (p, m):
 133                 #p.n = ~self._loopback + 2
 134                 p.n = p.n + 2
 135                 o = ObjectProxy(None)
 136                 o.a = p.n
 137                 o.b = p.o.b
 138                 p.o = o
 139             with pipe.Stage("third", p) as (p, m):
 140                 #p.n = ~self._loopback + 5
 141                 localv = Signal(4)
 142                 m.d.comb += localv.eq(2)
 143                 p.n = p.n << localv
 144                 o = ObjectProxy(None)
 145                 o.b = p.n + p.o.a + p.o.b
 146                 p.o = o
 147
 148         print (pipe.stages)
 149
 150         return m
 151
 152
 153
 154 if __name__ == "__main__":
 155     example = PipeModule()
 156     with open("pipe_module.il", "w") as f:
 157         f.write(rtlil.convert(example, ports=[
 158                example.p._loopback,
 159              ]))
 160     example = PipelineStageExample()
 161     with open("pipe_stage_module.il", "w") as f:
 162         f.write(rtlil.convert(example, ports=[
 163                example._loopback,
 164              ]))
 165     example = PipelineStageObjectExample()
 166     with open("pipe_stage_object_module.il", "w") as f:
 167         f.write(rtlil.convert(example, ports=[
 168                example._loopback,
 169              ]))