From bf41ae9a1ace70834f502b0cf4da123874c3345e Mon Sep 17 00:00:00 2001
From: Luke Kenneth Casson Leighton <lkcl@lkcl.net>
Date: Sat, 23 May 2020 18:40:49 +0100
Subject: [PATCH] add notes on FunctionUnit API

---
 src/soc/experiment/compalu_multi.py |  3 +-
 src/soc/fu/compunits.py             | 63 +++++++++++++++++++++++++++++
 2 files changed, 64 insertions(+), 2 deletions(-)
 create mode 100644 src/soc/fu/compunits.py

diff --git a/src/soc/experiment/compalu_multi.py b/src/soc/experiment/compalu_multi.py
index 89e4c6ee..3e41739c 100644
--- a/src/soc/experiment/compalu_multi.py
+++ b/src/soc/experiment/compalu_multi.py
@@ -153,6 +153,7 @@ class CompUnitRecord(RecordObject):
             return self._rwid
         return get_regspec_bitwidth(self._rwid, 0, i)
 
+
 class MultiCompUnit(Elaboratable):
     def __init__(self, rwid, alu, opsubsetkls, n_src=2, n_dst=1):
         """MultiCompUnit
@@ -203,14 +204,12 @@ class MultiCompUnit(Elaboratable):
         if isinstance(self.rwid, int): # old - testing - API (rwid is int)
             return self.alu.out[i]
         # regspec-based API: look up variable through regspec according to row number
-        print ("get out", dir(self.alu.n.data_o))
         return getattr(self.alu.n.data_o, self.rwid[1][i][1])
 
     def get_in(self, i):
         if isinstance(self.rwid, int): # old - testing - API (rwid is int)
             return self.alu.i[i]
         # regspec-based API: look up variable through regspec according to row number
-        print ("get in", dir(self.alu.p.data_i))
         return getattr(self.alu.p.data_i, self.rwid[0][i][1])
 
     def get_op(self):
diff --git a/src/soc/fu/compunits.py b/src/soc/fu/compunits.py
new file mode 100644
index 00000000..68d42d88
--- /dev/null
+++ b/src/soc/fu/compunits.py
@@ -0,0 +1,63 @@
+"""
+* see https://libre-soc.org/3d_gpu/architecture/regfile/ section on regspecs
+
+"""
+
+from nmigen.cli import rtlil
+from soc.experiment.compalu_multi import MultiCompUnit
+
+from soc.fu.alu.pipeline import ALUBasePipe
+from soc.fu.alu.pipe_data import ALUPipeSpec
+
+from soc.fu.cr.pipeline import CRBasePipe
+from soc.fu.cr.pipe_data import CRPipeSpec
+
+
+class FunctionUnitBaseSingle(MultiCompUnit):
+    """FunctionUnitBaseSingle
+
+    main "glue" class that brings everything together.
+    ONLY use this class for single-stage pipelines.
+
+    * :speckls:  - the specification.  contains regspec and op subset info,
+                   and contains common "stuff" like the pipeline ctx,
+                   what type of nmutil pipeline base is to be used (etc)
+    * :pipekls:  - the type of pipeline.  actually connects things together
+
+    note that it is through MultiCompUnit.get_in/out that we *actually*
+    connect up the association between regspec variable names (defined
+    in the pipe_data).
+    """
+    def __init__(self, speckls, pipekls):
+        pspec = speckls(id_wid=2)                # spec (NNNPipeSpec instance)
+        opsubset = pspec.opsubsetkls             # get the operand subset class
+        regspec = pspec.regspec                  # get the regspec
+        alu = pipekls(pspec)                     # create actual NNNBasePipe
+        super().__init__(regspec, alu, opsubset) # pass to MultiCompUnit
+
+
+######################################################################
+###### actual Function Units: these are "single" stage pipelines #####
+
+class ALUFunctionUnit(FunctionUnitBaseSingle):
+    def __init__(self): super().__init__(ALUPipeSpec, ALUBasePipe)
+
+class CRFunctionUnit(FunctionUnitBaseSingle):
+    def __init__(self): super().__init__(CRPipeSpec, CRBasePipe)
+
+#####################################################################
+###### actual Function Units: these are "multi" stage pipelines #####
+
+# TODO: ReservationStations-based.
+
+
+def tst_single_fus_il():
+    for (name, kls) in (('alu', ALUFunctionUnit),
+                        ('cr', CRFunctionUnit)):
+        fu = kls()
+        vl = rtlil.convert(fu, ports=fu.ports())
+        with open("fu_%s.il" % name, "w") as f:
+            f.write(vl)
+
+if __name__ == '__main__':
+    tst_single_fus_il()
-- 
2.30.2