X-Git-Url: https://git.libre-soc.org/?a=blobdiff_plain;f=src%2Fadd%2Fexample_buf_pipe.py;h=6d13099b93dc549b03598a43cb13cbc876681715;hb=5aa2f167e98633cc1cf2e896d717a132e8d1721b;hp=a1f5d04f565c1ec3cd1d2f813ca3fd9436fa6216;hpb=749ea1efc895d5259e49062bd9025dd6b1051636;p=ieee754fpu.git

diff --git a/src/add/example_buf_pipe.py b/src/add/example_buf_pipe.py
index a1f5d04f..6d13099b 100644
--- a/src/add/example_buf_pipe.py
+++ b/src/add/example_buf_pipe.py
@@ -52,13 +52,15 @@ from collections.abc import Sequence
 
 class PrevControl:
     """ contains signals that come *from* the previous stage (both in and out)
-        * i_valid: input from previous stage indicating incoming data is valid
+        * i_valid: previous stage indicating all incoming data is valid.
+                   may be a multi-bit signal, where all bits are required
+                   to be asserted to indicate "valid".
         * o_ready: output to next stage indicating readiness to accept data
         * i_data : an input - added by the user of this class
     """
 
-    def __init__(self):
-        self.i_valid = Signal(name="p_i_valid") # prev   >>in  self
+    def __init__(self, i_width=1):
+        self.i_valid = Signal(i_width, name="p_i_valid") # prev   >>in  self
         self.o_ready = Signal(name="p_o_ready") # prev   <<out self
 
     def connect_in(self, prev):
@@ -105,6 +107,11 @@ def eq(o, i):
         passsed a list (or tuple) of objects, and calls the objects' eq
         function.
 
+        complex objects (classes) can be used: they must follow the
+        convention of having an eq member function, which takes the
+        responsibility of further calling eq and returning a list of
+        eq assignments
+
         Record is a special (unusual, recursive) case, where the input
         is specified as a dictionary (which may contain further dictionaries,
         recursively), where the field names of the dictionary must match
@@ -130,12 +137,13 @@ def eq(o, i):
 class PipelineBase:
     """ Common functions for Pipeline API
     """
-    def __init__(self, stage):
+    def __init__(self, stage, in_multi=None):
         """ pass in a "stage" which may be either a static class or a class
-            instance, which has three functions:
+            instance, which has four functions (one optional):
             * ispec: returns input signals according to the input specification
             * ispec: returns output signals to the output specification
             * process: takes an input instance and returns processed data
+            * setup: performs any module linkage if the stage uses one.
 
             User must also:
             * add i_data member to PrevControl and
@@ -144,7 +152,7 @@ class PipelineBase:
         self.stage = stage
 
         # set up input and output IO ACK (prev/next ready/valid)
-        self.p = PrevControl()
+        self.p = PrevControl(in_multi)
         self.n = NextControl()
 
     def connect_to_next(self, nxt):
@@ -219,10 +227,17 @@ class BufferedPipeline(PipelineBase):
             self.stage.setup(m, self.p.i_data)
 
         # establish some combinatorial temporaries
+        p_i_valid = Signal(reset_less=True)
         o_n_validn = Signal(reset_less=True)
         i_p_valid_o_p_ready = Signal(reset_less=True)
-        m.d.comb += [o_n_validn.eq(~self.n.o_valid),
-                     i_p_valid_o_p_ready.eq(self.p.i_valid & self.p.o_ready),
+        vlen = len(self.p.i_valid)
+        if vlen > 1: # multi-bit case: valid only when i_valid is all 1s
+            all1s = Const(-1, (len(self.p.i_valid), False))
+            m.d.comb += p_i_valid.eq(self.p.i_valid == all1s)
+        else: # single-bit i_valid case
+            m.d.comb += p_i_valid.eq(self.p.i_valid)
+        m.d.comb += [ o_n_validn.eq(~self.n.o_valid),
+                     i_p_valid_o_p_ready.eq(p_i_valid & self.p.o_ready),
         ]
 
         # store result of processing in combinatorial temporary
@@ -238,7 +253,7 @@ class BufferedPipeline(PipelineBase):
         with m.If(self.n.i_ready): # next stage is ready
             with m.If(self.p.o_ready): # not stalled
                 # nothing in buffer: send (processed) input direct to output
-                m.d.sync += [self.n.o_valid.eq(self.p.i_valid),
+                m.d.sync += [self.n.o_valid.eq(p_i_valid),
                              eq(self.n.o_data, result), # update output
                             ]
             with m.Else(): # p.o_ready is false, and something is in buffer.
@@ -252,7 +267,7 @@ class BufferedPipeline(PipelineBase):
 
         # (n.i_ready) is false here: next stage is ready
         with m.Elif(o_n_validn): # next stage being told "ready"
-            m.d.sync += [self.n.o_valid.eq(self.p.i_valid),
+            m.d.sync += [self.n.o_valid.eq(p_i_valid),
                          self.p.o_ready.eq(1), # Keep the buffer empty
                          # set the output data (from comb result)
                          eq(self.n.o_data, result),
@@ -260,7 +275,7 @@ class BufferedPipeline(PipelineBase):
         # (n.i_ready) false and (n.o_valid) true:
         with m.Elif(i_p_valid_o_p_ready):
             # If next stage *is* ready, and not stalled yet, accept input
-            m.d.sync += self.p.o_ready.eq(~(self.p.i_valid & self.n.o_valid))
+            m.d.sync += self.p.o_ready.eq(~(p_i_valid & self.n.o_valid))
 
         return m
 
@@ -324,24 +339,15 @@ class CombPipe(PipelineBase):
     """A simple pipeline stage containing combinational logic that can execute
     completely in one clock cycle.
 
-    Parameters:
-    -----------
-    input_shape : int or tuple or None
-        the shape of ``input.data`` and ``comb_input``
-    output_shape : int or tuple or None
-        the shape of ``output.data`` and ``comb_output``
-    name : str
-        the name
-
     Attributes:
     -----------
     input : StageInput
         The pipeline input
     output : StageOutput
         The pipeline output
-    comb_input : Signal, input_shape
-        The input to the combinatorial logic
-    comb_output: Signal, output_shape
+    r_data : Signal, input_shape
+        A temporary (buffered) copy of a prior (valid) input
+    result: Signal, output_shape
         The output of the combinatorial logic
     """