From 9eba6f1517e65d0a4450af2e68af7177d17367cd Mon Sep 17 00:00:00 2001
From: Curt Coder <curtcoder@mail.com>
Date: Tue, 2 Jun 2009 06:49:59 +0000
Subject: [PATCH] [Z80PIO] Added alternate read/write handlers.

---
 src/emu/machine/z80pio.c | 14 ++++++++++++++
 src/emu/machine/z80pio.h |  2 ++
 2 files changed, 16 insertions(+)

diff --git a/src/emu/machine/z80pio.c b/src/emu/machine/z80pio.c
index 1070450a3f4..6643251b43a 100644
--- a/src/emu/machine/z80pio.c
+++ b/src/emu/machine/z80pio.c
@@ -532,6 +532,20 @@ WRITE8_DEVICE_HANDLER(z80pio_w)
 		z80pio_d_w(device, offset & 1, data);
 }
 
+READ8_DEVICE_HANDLER(z80pio_alt_r)
+{
+	int channel = BIT(offset, 1);
+	return (offset & 1) ? z80pio_c_r(device, channel) : z80pio_d_r(device, channel);
+}
+
+WRITE8_DEVICE_HANDLER(z80pio_alt_w)
+{
+	int channel = BIT(offset, 1);
+	if (offset & 1)
+		z80pio_c_w(device, channel, data);
+	else
+		z80pio_d_w(device, channel, data);
+}
 
 static DEVICE_START( z80pio )
 {
diff --git a/src/emu/machine/z80pio.h b/src/emu/machine/z80pio.h
index 9b7b490d4ba..187210f8434 100644
--- a/src/emu/machine/z80pio.h
+++ b/src/emu/machine/z80pio.h
@@ -104,6 +104,8 @@ void z80pio_bstb_w(const device_config *device, int state);
 ***************************************************************************/
 READ8_DEVICE_HANDLER(z80pio_r);
 WRITE8_DEVICE_HANDLER(z80pio_w);
+READ8_DEVICE_HANDLER(z80pio_alt_r);
+WRITE8_DEVICE_HANDLER(z80pio_alt_w);
 
 
 /* ----- device interface ----- */