From dfd6d4e2df6f22bdd18c0c40c422db5b4f97c25a Mon Sep 17 00:00:00 2001
From: RichardG867 <richardg867@gmail.com>
Date: Thu, 3 Jun 2021 01:14:48 -0300
Subject: [PATCH] Add game port device with 6 I/O ports for the Crystal
 CS4237/8B

---
 src/game/gameport.c          | 25 ++++++++++++++++++-------
 src/include/86box/gameport.h |  1 +
 src/sound/snd_cs423x.c       |  7 ++++---
 3 files changed, 23 insertions(+), 10 deletions(-)

diff --git a/src/game/gameport.c b/src/game/gameport.c
index 2c56f13b8..d33efb897 100644
--- a/src/game/gameport.c
+++ b/src/game/gameport.c
@@ -45,6 +45,7 @@ typedef struct {
 
 typedef struct _gameport_ {
     uint16_t	addr;
+    uint8_t	len;
     struct _joystick_instance_ *joystick;
     struct _gameport_ *next;
 } gameport_t;
@@ -314,7 +315,7 @@ gameport_remap(void *priv, uint16_t address)
 		}
 	}
 
-	io_removehandler(dev->addr, (dev->addr & 1) ? 1 : 8,
+	io_removehandler(dev->addr, dev->len,
 			 gameport_read, NULL, NULL, gameport_write, NULL, NULL, dev);
     }
 
@@ -334,7 +335,7 @@ gameport_remap(void *priv, uint16_t address)
 		other_dev->next = dev;
 	}
 
-	io_sethandler(dev->addr, (dev->addr & 1) ? 1 : 8,
+	io_sethandler(dev->addr, dev->len,
 		      gameport_read, NULL, NULL, gameport_write, NULL, NULL, dev);
     }
 }
@@ -358,7 +359,7 @@ gameport_add(const device_t *gameport_type)
 {
     /* Prevent a standalone game port from being added later on, unless this
        is an unused Super I/O game port (no MACHINE_GAMEPORT machine flag). */
-    if (!(gameport_type->local & 0x10000) || (machines[machine].flags & MACHINE_GAMEPORT))
+    if (!(gameport_type->local & 0x1000000) || (machines[machine].flags & MACHINE_GAMEPORT))
 	standalone_gameport_type = NULL;
 
     /* Add game port device. */
@@ -401,6 +402,7 @@ gameport_init(const device_t *info)
     dev->joystick = joystick_instance;
 
     /* Map game port to the default address. Not applicable on PnP-only ports. */
+    dev->len = (info->local >> 16) & 0xff;
     gameport_remap(dev, info->local & 0xffff);
 
     /* Register ISAPnP if this is a standard game port card. */
@@ -433,7 +435,7 @@ gameport_close(void *priv)
 
 const device_t gameport_device = {
     "Game port",
-    0, 0x200,
+    0, 0x080200,
     gameport_init,
     gameport_close,
     NULL, { NULL }, NULL,
@@ -442,7 +444,7 @@ const device_t gameport_device = {
 
 const device_t gameport_201_device = {
     "Game port (port 201h only)",
-    0, 0x201,
+    0, 0x010201,
     gameport_init,
     gameport_close,
     NULL, { NULL }, NULL,
@@ -451,7 +453,16 @@ const device_t gameport_201_device = {
 
 const device_t gameport_pnp_device = {
     "Game port (Plug and Play only)",
-    0, 0,
+    0, 0x080000,
+    gameport_init,
+    gameport_close,
+    NULL, { NULL }, NULL,
+    NULL
+};
+
+const device_t gameport_pnp_6io_device = {
+    "Game port (Plug and Play only, 6 I/O ports)",
+    0, 0x060000,
     gameport_init,
     gameport_close,
     NULL, { NULL }, NULL,
@@ -460,7 +471,7 @@ const device_t gameport_pnp_device = {
 
 const device_t gameport_sio_device = {
     "Game port (Super I/O)",
-    0, 0x10000,
+    0, 0x1080000,
     gameport_init,
     gameport_close,
     NULL, { NULL }, NULL,
diff --git a/src/include/86box/gameport.h b/src/include/86box/gameport.h
index 9f5da7f00..be8eec813 100644
--- a/src/include/86box/gameport.h
+++ b/src/include/86box/gameport.h
@@ -108,6 +108,7 @@ extern "C" {
 extern const device_t	gameport_device;
 extern const device_t	gameport_201_device;
 extern const device_t	gameport_pnp_device;
+extern const device_t	gameport_pnp_6io_device;
 extern const device_t	gameport_sio_device;
 
 extern const device_t	*standalone_gameport_type;
diff --git a/src/sound/snd_cs423x.c b/src/sound/snd_cs423x.c
index 57bf083ca..fbc8595b1 100644
--- a/src/sound/snd_cs423x.c
+++ b/src/sound/snd_cs423x.c
@@ -720,6 +720,10 @@ cs423x_init(const device_t *info)
 				break;
 		}
 
+		/* Initialize game port. The '7B and '8B game port only responds to 6 I/O ports; the remaining
+		   2 ports are reserved on those chips, and probably connected to the Digital Assist feature. */
+		dev->gameport = gameport_add((dev->type == CRYSTAL_CS4236B) ? &gameport_pnp_device : &gameport_pnp_6io_device);
+
 		break;
     }
 
@@ -731,9 +735,6 @@ cs423x_init(const device_t *info)
     cs423x_reset(dev);
     sound_add_handler(cs423x_get_buffer, dev);
 
-    /* Initialize game port. */
-    dev->gameport = gameport_add(&gameport_pnp_device);
-
     /* Initialize I2C bus for the EEPROM. */
     dev->i2c = i2c_gpio_init("nvr_cs423x");