From: Paul Mackerras <paulus@ozlabs.org>
Date: Sat, 21 Nov 2020 02:54:14 +0000 (+1100)
Subject: execute1: Fix writing LR for bdnzl/bdzl instructions
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=27ac74a3415d894437d5a3b146d270615c637f6f;p=microwatt.git

execute1: Fix writing LR for bdnzl/bdzl instructions

Branch instructions which do a redirect and write both CTR and LR were
not doing the write to LR due to a logic error.  This fixes it.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
---

diff --git a/execute1.vhdl b/execute1.vhdl
index de6bd25..61df974 100644
--- a/execute1.vhdl
+++ b/execute1.vhdl
@@ -1131,10 +1131,16 @@ begin
             if e_in.insn_type = OP_FETCH_FAILED then
                 do_trace := '0';
             end if;
+        end if;
+
+        -- The following cases all occur when r.busy = 1 and therefore
+        -- valid_in = 0.  Hence they don't happen in the same cycle as any of
+        -- the cases above which depend on valid_in = 1.
 
-        elsif r.f.redirect = '1' then
+        if r.f.redirect = '1' then
             v.e.valid := '1';
-	elsif r.lr_update = '1' then
+        end if;
+	if r.lr_update = '1' then
             v.e.exc_write_enable := '1';
 	    v.e.exc_write_data := r.next_lr;
 	    v.e.exc_write_reg := fast_spr_num(SPR_LR);