From 5667e081a0b6243cb2ce14f55fb330aa6e07a6ad Mon Sep 17 00:00:00 2001
From: Gyorgy Szombathelyi <gyurco@freemail.hu>
Date: Mon, 3 Sep 2018 03:26:18 +0200
Subject: [PATCH] C16: [T65] fix SO signal samping

---
 cores/c16/t65/T65.vhd | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/cores/c16/t65/T65.vhd b/cores/c16/t65/T65.vhd
index b9fa335..d6aba9c 100755
--- a/cores/c16/t65/T65.vhd
+++ b/cores/c16/t65/T65.vhd
@@ -463,9 +463,6 @@ begin
             --This should happen after P has been pushed to stack
             tmpP(Flag_I) := '1';
           end if;
-          if SO_n_o = '1' and SO_n = '0' then
-            tmpP(Flag_V) := '1';
-          end if;
           if RstCycle = '1' then
             tmpP(Flag_I) := '1';
             tmpP(Flag_D) := '0';
@@ -474,7 +471,6 @@ begin
 
           P<=tmpP;--new way
 
-          SO_n_o <= SO_n;
           if IR(4 downto 0)/="10000" or Jump/="01" then -- delay interrupts during branches (checked with Lorenz test and real 6510), not best way yet, though - but works...
             IRQ_n_o <= IRQ_n;
           end if;
@@ -484,6 +480,13 @@ begin
           NMI_n_o <= NMI_n;
         end if;
       end if;
+      -- act immediately on SO pin change
+      -- The signal is sampled on the trailing edge of phi1 and must be externally synchronized (from datasheet)
+      SO_n_o <= SO_n;
+		if SO_n_o = '1' and SO_n = '0' then
+          P(Flag_V) <= '1';
+      end if;
+
     end if;
   end process;