From 08fdc65d69f5d24d71f8aff63a78bd5cd5ec3f3f Mon Sep 17 00:00:00 2001
From: Gyorgy Szombathelyi <gyurco@freemail.hu>
Date: Mon, 23 Mar 2020 16:12:05 +0100
Subject: [PATCH] [C64] T65: detect IRQ even when not RDY

Fixes Tsunami demo

Waiting for RDY while the interrupt already asserted causes too much
delay. The interrupt cycle will still start at the correct position,
as soon as the RDY line is de-asserted, and other conditions are satisfied.
---
 cores/c64/rtl/t65/T65.vhd | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/cores/c64/rtl/t65/T65.vhd b/cores/c64/rtl/t65/T65.vhd
index 90bf886..66df868 100755
--- a/cores/c64/rtl/t65/T65.vhd
+++ b/cores/c64/rtl/t65/T65.vhd
@@ -474,9 +474,11 @@ begin
 
           P<=tmpP;--new way
 
-          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;
+        end if;
+
+        -- detect irq even if not rdy
+        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;
         -- detect nmi even if not rdy
         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...