From: Martin Meloun <meloumar@cmp.felk.cvut.cz>
Date: Thu, 19 Sep 2013 19:17:48 +0000 (+0200)
Subject: When branching, do not execute the instruction behind the branch
X-Git-Url: http://rtime.felk.cvut.cz/gitweb/fpga/lx-cpu1/tumbl.git/commitdiff_plain/9b3c6c50afd73593508f59b83ea3ec5d23906736

When branching, do not execute the instruction behind the branch

Note: To effectively use this feature, gcc requires patching
---

diff --git a/hw/core_ctrl.vhd b/hw/core_ctrl.vhd
index da5752b..5e9d5a4 100644
--- a/hw/core_ctrl.vhd
+++ b/hw/core_ctrl.vhd
@@ -257,7 +257,11 @@ regd_proc:
                 lp_rst_ID2EX_REG;
             ELSIF (clken_pipe_s = '1') THEN
                 setup_int_r <= '0';
-                ID2EX_REG_r <= ID2EX_REG_i;
+                if (EX2IF_REG_i.take_branch = '1') THEN
+                    lp_rst_ID2EX_REG;
+                ELSE
+                    ID2EX_REG_r <= ID2EX_REG_i;
+                END IF;
                 delayBit_r  <= ID2CTRL_i.delayBit;
             END IF;
             -- exeq-to-mem unit registers