X-Git-Url: https://git.libre-soc.org/?a=blobdiff_plain;f=src%2Fexperiment%2Fcompalu.py;h=1f3b90512e1d8940f9be7d096c2390c2ac12bd63;hb=298b4165b1a7eafff5c5b93bc926f6736899c8be;hp=74489360d1a3a10dc892471781515110a2dc03d3;hpb=d888bf3415f6aca6aa31148445065dc89f0c5ce2;p=soc.git

diff --git a/src/experiment/compalu.py b/src/experiment/compalu.py
index 74489360..1f3b9051 100644
--- a/src/experiment/compalu.py
+++ b/src/experiment/compalu.py
@@ -18,7 +18,7 @@ from nmutil.latch import SRLatch, latchregister
       The src1 and src2 registers and the operand can be latched in
       at this point
 
-    * Read request is set, which is ackowledged through the Scoreboard
+    * Read request is set, which is acknowledged through the Scoreboard
       to the priority picker, which generates (one and only one) Go_Read
       at a time.  One of those will (eventually) be this Computation Unit.
 
@@ -69,10 +69,8 @@ class ComputationUnitNoDelay(Elaboratable):
         # shadow/go_die
         reset_w = Signal(reset_less=True)
         reset_r = Signal(reset_less=True)
-        #m.d.comb += reset_w.eq(self.go_wr_i)# | self.go_die_i)
-        #m.d.comb += reset_r.eq(self.go_rd_i)# | self.go_die_i)
-        reset_w = self.go_wr_i
-        reset_r = self.go_rd_i
+        m.d.comb += reset_w.eq(self.go_wr_i | self.go_die_i)
+        m.d.comb += reset_r.eq(self.go_rd_i | self.go_die_i)
 
         # This is fascinating and very important to observe that this
         # is in effect a "3-way revolving door".  At no time may all 3
@@ -98,6 +96,8 @@ class ComputationUnitNoDelay(Elaboratable):
         m.d.comb += self.busy_o.eq(opc_l.q) # busy out
         m.d.comb += self.rd_rel_o.eq(src_l.q & opc_l.q) # src1/src2 req rel
 
+        # the counter is just for demo purposes, to get the ALUs of different
+        # types to take arbitrary completion times
         with m.If(opc_l.qn):
             m.d.sync += self.counter.eq(0)
         with m.If(req_l.qn & opc_l.q & (self.counter == 0)):
@@ -105,13 +105,15 @@ class ComputationUnitNoDelay(Elaboratable):
                 m.d.sync += self.counter.eq(5)
             with m.Elif(self.oper_i == 3): # SHIFT to take 7
                 m.d.sync += self.counter.eq(7)
+            with m.Elif(self.oper_i >= 4): # Branches take 6 (to test shadow)
+                m.d.sync += self.counter.eq(6)
             with m.Else(): # ADD/SUB to take 2
                 m.d.sync += self.counter.eq(2)
         with m.If(self.counter > 1):
             m.d.sync += self.counter.eq(self.counter - 1)
         with m.If(self.counter == 1):
             # write req release out.  waits until shadow is dropped.
-            m.d.comb += self.req_rel_o.eq(req_l.q & opc_l.q)# & self.shadown_i)
+            m.d.comb += self.req_rel_o.eq(req_l.q & opc_l.q & self.shadown_i)
 
         # create a latch/register for src1/src2
         latchregister(m, self.src1_i, self.alu.a, src_l.q)