From b0e08dff9a4ff71333321b931d4155479f35428e Mon Sep 17 00:00:00 2001
From: notaz <notasas@gmail.com>
Date: Tue, 26 Sep 2017 02:59:31 +0300
Subject: [PATCH] allow limited z80 vdp access

lame and totally wrong timing
---
 pico/memory.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/pico/memory.c b/pico/memory.c
index 83fe1819..cb1b5ac3 100644
--- a/pico/memory.c
+++ b/pico/memory.c
@@ -1165,7 +1165,9 @@ void PicoWrite16_32x(u32 a, u32 d) {}
 
 static unsigned char z80_md_vdp_read(unsigned short a)
 {
-  // TODO?
+  if ((a & 0x00e0) == 0x0000)
+    return PicoVideoRead8(a); // FIXME: depends on 68k cycles
+
   elprintf(EL_ANOMALY, "z80 invalid r8 [%06x] %02x", a, 0xff);
   return 0xff;
 }
@@ -1192,13 +1194,13 @@ static void z80_md_ym2612_write(unsigned int a, unsigned char data)
 
 static void z80_md_vdp_br_write(unsigned int a, unsigned char data)
 {
-  // TODO: allow full VDP access
   if ((a&0xfff9) == 0x7f11) // 7f11 7f13 7f15 7f17
   {
     if (PicoOpt & POPT_EN_PSG)
       SN76496Write(data);
     return;
   }
+  // at least VDP data writes hang my machine
 
   if ((a>>8) == 0x60)
   {
-- 
2.39.5