turn CompALU/CompLDST latches synchronous

to cut down combinatorial loops

diff --git a/src/soc/experiment/compalu_multi.py b/src/soc/experiment/compalu_multi.py
index d33be619d01ddac18539a7873da644ae7fa190c8..3d1f7249af461fea77452dce19cdc57267330d13 100644 (file)
--- a/src/soc/experiment/compalu_multi.py
+++ b/src/soc/experiment/compalu_multi.py
@@ -258,7 +258,7 @@ class MultiCompUnit(RegSpecALUAPI, Elaboratable):
         # src operand latch (not using go_wr_i) ANDed with rdmask
         rdmaskn = Signal(self.n_src)
         latchregister(m, self.rdmaskn, rdmaskn, self.issue_i, name="rdmask_l")
-        m.d.comb += src_l.s.eq(Repl(self.issue_i, self.n_src) & ~rdmaskn)
+        m.d.sync += src_l.s.eq(Repl(self.issue_i, self.n_src) & ~rdmaskn)
         m.d.sync += src_l.r.eq(reset_r)
 
         # dest operand latch (not using issue_i)

diff --git a/src/soc/experiment/compldst_multi.py b/src/soc/experiment/compldst_multi.py
index 094fbc6dcd65df4eeaee36549e4a7bd86ce8f659..2a54e51bf0caacddd0af4df62b7facb45c1a6395 100644 (file)
--- a/src/soc/experiment/compldst_multi.py
+++ b/src/soc/experiment/compldst_multi.py
@@ -266,7 +266,7 @@ class LDSTCompUnit(RegSpecAPI, Elaboratable):
 
         #####################
         # latches for the FSM.
-        m.submodules.opc_l = opc_l = SRLatch(sync=False, name="opc")
+        m.submodules.opc_l = opc_l = SRLatch(sync=True, name="opc")
         m.submodules.src_l = src_l = SRLatch(False, self.n_src, name="src")
         m.submodules.alu_l = alu_l = SRLatch(sync=False, name="alu")
         m.submodules.adr_l = adr_l = SRLatch(sync=False, name="adr")
@@ -372,8 +372,8 @@ class LDSTCompUnit(RegSpecAPI, Elaboratable):
         # opcode latch - inverted so that busy resets to 0
         # note this MUST be sync so as to avoid a combinatorial loop
         # between busy_o and issue_i on the reset latch (rst_l)
-        sync += opc_l.s.eq(issue_i)  # XXX NOTE: INVERTED FROM book!
-        sync += opc_l.r.eq(reset_o)  # XXX NOTE: INVERTED FROM book!
+        comb += opc_l.s.eq(issue_i)  # XXX NOTE: INVERTED FROM book!
+        comb += opc_l.r.eq(reset_o)  # XXX NOTE: INVERTED FROM book!
 
         # src operand latch
         sync += src_l.s.eq(Repl(issue_i, self.n_src) & ~self.rdmaskn)