eater: PC inc included, decode on negedgemain

Some cycles can be saved.
As previously (wrongly) committed, the PC can be incremented early,
but the decoder needs to do this "early", so as now implemented,
on the falling clock adge already.

1 files changed, 4 insertions, 1 deletions

diff --git a/eater_cpu/eater_computer.sv b/eater_cpu/eater_computer.sv
index 6569831..2fca29e 100644
--- a/eater_cpu/eater_computer.sv
+++ b/eater_cpu/eater_computer.sv
@@ -167,8 +167,11 @@ eater_register OUT (
   .always_out(OUT_out)
 );
 
+// run decoder on negated clock,
+// allowing stuff to be clocked in "early"
+wire DEC_clk_neg = ~clk_in;
 eater_decoder decoder (
-  .clk_i(clk_in),
+  .clk_i(DEC_clk_neg),
   .instruction_i(INS_out),
   .flags_o(automatic_flags)
 );