From 13e8d9c923ef3198c91aa942aaf8af865968a396 Mon Sep 17 00:00:00 2001
From: OBattler <oubattler@gmail.com>
Date: Tue, 30 Jun 2020 03:24:06 +0200
Subject: [PATCH] Fixed Shadow RAM handling for all OPTi 486 chipsets.

---
 src/chipset/opti495.c | 30 ++++++++++++++++--------------
 src/chipset/opti895.c | 30 ++++++++++++++++--------------
 2 files changed, 32 insertions(+), 28 deletions(-)

diff --git a/src/chipset/opti495.c b/src/chipset/opti495.c
index c192062a7..c3fa1bda4 100644
--- a/src/chipset/opti495.c
+++ b/src/chipset/opti495.c
@@ -90,14 +90,15 @@ opti495_recalc(opti495_t *dev)
 
 	if ((dev->regs[0x22] & ((base >= 0xe0000) ? 0x20 : 0x40)) &&
 	    (dev->regs[0x23] & (1 << i))) {
-		if (dev->regs[0x26] & 0x40)
-			shflags = MEM_READ_EXTANY | MEM_WRITE_INTERNAL;
-		else {
-			shflags = MEM_READ_INTERNAL;
+		shflags = MEM_READ_INTERNAL;
+		shflags |= (dev->regs[0x22] & ((base >= 0xe0000) ? 0x08 : 0x10)) ? MEM_WRITE_DISABLED : MEM_WRITE_INTERNAL;
+	} else {
+		if (dev->regs[0x26] & 0x40) {
+			shflags = MEM_READ_EXTANY;
 			shflags |= (dev->regs[0x22] & ((base >= 0xe0000) ? 0x08 : 0x10)) ? MEM_WRITE_DISABLED : MEM_WRITE_INTERNAL;
-		}
-	} else
-		shflags = MEM_READ_EXTANY | MEM_WRITE_EXTANY;
+		} else
+			shflags = MEM_READ_EXTANY | MEM_WRITE_EXTANY;
+	}
 
 	mem_set_mem_state_both(base, 0x4000, shflags);
     }
@@ -106,14 +107,15 @@ opti495_recalc(opti495_t *dev)
 	base = 0xc0000 + (i << 14);
 
 	if ((dev->regs[0x26] & 0x10) && (dev->regs[0x26] & (1 << i))) {
-		if (dev->regs[0x26] & 0x40)
-			shflags = MEM_READ_EXTANY | MEM_WRITE_INTERNAL;
-		else {
-			shflags = MEM_READ_INTERNAL;
+		shflags = MEM_READ_INTERNAL;
+		shflags |= (dev->regs[0x26] & 0x20) ? MEM_WRITE_DISABLED : MEM_WRITE_INTERNAL;
+	} else {
+		if (dev->regs[0x26] & 0x40) {
+			shflags = MEM_READ_EXTANY;
 			shflags |= (dev->regs[0x26] & 0x20) ? MEM_WRITE_DISABLED : MEM_WRITE_INTERNAL;
-		}
-	} else
-		shflags = MEM_READ_EXTANY | MEM_WRITE_EXTANY;
+		} else
+			shflags = MEM_READ_EXTANY | MEM_WRITE_EXTANY;
+	}
 
 	mem_set_mem_state_both(base, 0x4000, shflags);
     }
diff --git a/src/chipset/opti895.c b/src/chipset/opti895.c
index a01bf099d..8c1f050b4 100644
--- a/src/chipset/opti895.c
+++ b/src/chipset/opti895.c
@@ -89,14 +89,15 @@ opti895_recalc(opti895_t *dev)
 	base = 0xd0000 + (i << 14);
 
 	if (dev->regs[0x23] & (1 << i)) {
-		if (dev->regs[0x26] & 0x40)
-			shflags = MEM_READ_EXTANY | MEM_WRITE_INTERNAL;
-		else {
-			shflags = MEM_READ_INTERNAL;
+		shflags = MEM_READ_INTERNAL;
+		shflags |= (dev->regs[0x22] & ((base >= 0xe0000) ? 0x08 : 0x10)) ? MEM_WRITE_DISABLED : MEM_WRITE_INTERNAL;
+	} else {
+		if (dev->regs[0x26] & 0x40) {
+			shflags = MEM_READ_EXTANY;
 			shflags |= (dev->regs[0x22] & ((base >= 0xe0000) ? 0x08 : 0x10)) ? MEM_WRITE_DISABLED : MEM_WRITE_INTERNAL;
-		}
-	} else
-		shflags = MEM_READ_EXTANY | MEM_WRITE_EXTANY;
+		} else
+			shflags = MEM_READ_EXTANY | MEM_WRITE_EXTANY;
+	}
 
 	mem_set_mem_state_both(base, 0x4000, shflags);
     }
@@ -105,14 +106,15 @@ opti895_recalc(opti895_t *dev)
 	base = 0xc0000 + (i << 14);
 
 	if (dev->regs[0x26] & (1 << i)) {
-		if (dev->regs[0x26] & 0x40)
-			shflags = MEM_READ_EXTANY | MEM_WRITE_INTERNAL;
-		else {
-			shflags = MEM_READ_INTERNAL;
+		shflags = MEM_READ_INTERNAL;
+		shflags |= (dev->regs[0x26] & 0x20) ? MEM_WRITE_DISABLED : MEM_WRITE_INTERNAL;
+	} else {
+		if (dev->regs[0x26] & 0x40) {
+			shflags = MEM_READ_EXTANY;
 			shflags |= (dev->regs[0x26] & 0x20) ? MEM_WRITE_DISABLED : MEM_WRITE_INTERNAL;
-		}
-	} else
-		shflags = MEM_READ_EXTANY | MEM_WRITE_EXTANY;
+		} else
+			shflags = MEM_READ_EXTANY | MEM_WRITE_EXTANY;
+	}
 
 	mem_set_mem_state_both(base, 0x4000, shflags);
     }