SCI: Move ScummVM kernel calls to 0xe0

5 files changed, 43 insertions, 17 deletions

diff --git a/engines/sci/engine/guest_additions.cpp b/engines/sci/engine/guest_additions.cpp
index 6477e3284b..8ac780ac17 100644
--- a/engines/sci/engine/guest_additions.cpp
+++ b/engines/sci/engine/guest_additions.cpp
@@ -315,10 +315,10 @@ void GuestAdditions::patchGameSaveRestoreSCI16() const {
 
 #ifdef ENABLE_SCI32
 static const byte SRDialogPatch[] = {
-	0x76,                   // push0
-	0x59, 0x00,             // &rest 0
-	0x43, 0x57, 0x00, 0x00, // callk kScummVMSaveLoad, 0
-	0x48                    // ret
+	0x76,                                 // push0
+	0x59, 0x01,                           // &rest 1
+	0x43, kScummVMSaveLoadId, 0x00, 0x00, // callk kScummVMSaveLoad, 0
+	0x48                                  // ret
 };
 
 void GuestAdditions::patchGameSaveRestoreSCI32(Script &script) const {
diff --git a/engines/sci/engine/kernel.cpp b/engines/sci/engine/kernel.cpp
index 13a836ab77..68a09e9935 100644
--- a/engines/sci/engine/kernel.cpp
+++ b/engines/sci/engine/kernel.cpp
@@ -905,11 +905,6 @@ void Kernel::loadKernelNames(GameFeatures *features) {
 		} else {
 			// Normal SCI2.1 kernel table
 			_kernelNames = Common::StringArray(sci21_default_knames, kKernelEntriesSci21);
-
-			// Used by script patcher to remove CPU spinning on kGetTime
-			if (g_sci->getGameId() == GID_HOYLE5) {
-				_kernelNames[0x4f] = "Wait";
-			}
 		}
 		break;
 
@@ -936,6 +931,32 @@ void Kernel::loadKernelNames(GameFeatures *features) {
 		break;
 	}
 
+#ifdef ENABLE_SCI32
+	// Reserve a high range of kernel call IDs (0xe0 to 0xef) that can be used
+	// by ScummVM to improve integration and fix bugs in games that require
+	// more help than can be provided by a simple script patch (e.g. spinloops
+	// in Hoyle5).
+	// Using a new high range instead of just replacing dummied kernel calls in
+	// the normal kernel range is intended to avoid any conflicts with fangames
+	// that might try to add their own kernel calls in the same manner. It also
+	// helps to separate ScummVM interpreter's kernel calls from SSCI's standard
+	// kernel calls.
+	if (getSciVersion() >= SCI_VERSION_2) {
+		const uint kernelListSize = _kernelNames.size();
+		_kernelNames.resize(0xe2);
+		for (uint id = kernelListSize; id < 0xe0; ++id) {
+			_kernelNames[id] = "Dummy";
+		}
+
+		// Used by Hoyle5 script patches to remove CPU spinning on kGetTime
+		// (this repurposes the existing SCI16 kWait call that was removed in SCI32)
+		_kernelNames[kScummVMWaitId] = "Wait";
+
+		// Used by GuestAdditions to support integrated save/load dialogue
+		_kernelNames[kScummVMSaveLoadId] = "ScummVMSaveLoad";
+	}
+#endif
+
 	mapFunctions();
 }
 
diff --git a/engines/sci/engine/kernel.h b/engines/sci/engine/kernel.h
index e5b84dd089..2b61a9e0d9 100644
--- a/engines/sci/engine/kernel.h
+++ b/engines/sci/engine/kernel.h
@@ -98,6 +98,11 @@ struct SciWorkaroundEntry;	// from workarounds.h
 
 // ---- Kernel signatures -----------------------------------------------------
 
+enum {
+	kScummVMWaitId     = 0xe0,
+	kScummVMSaveLoadId = 0xe1
+};
+
 // internal kernel signature data
 enum {
 	SIG_TYPE_NULL          =  0x01, // may be 0:0       [0]
diff --git a/engines/sci/engine/kernel_tables.h b/engines/sci/engine/kernel_tables.h
index 5dbd5a5f46..f075da3005 100644
--- a/engines/sci/engine/kernel_tables.h
+++ b/engines/sci/engine/kernel_tables.h
@@ -1264,7 +1264,7 @@ static const char *const sci2_default_knames[] = {
 	/*0x54*/ "Dummy",
 	/*0x55*/ "DeleteKey",
 	/*0x56*/ "Dummy",
-	/*0x57*/ "ScummVMSaveLoad", // Dummy in SSCI
+	/*0x57*/ "Dummy",
 	/*0x58*/ "ListAt",
 	/*0x59*/ "ListIndexOf",
 	/*0x5a*/ "ListEachElementDo",
@@ -1428,7 +1428,7 @@ static const char *const sci21_default_knames[] = {
 	/*0x54*/ "HaveMouse",
 	/*0x55*/ "SetCursor",
 	/*0x56*/ "VibrateMouse",	// Dummy in SCI3
-	/*0x57*/ "ScummVMSaveLoad", // Dummy in SSCI
+	/*0x57*/ "Dummy",
 	/*0x58*/ "Dummy",
 	/*0x59*/ "Dummy",
 	/*0x5a*/ "List",
diff --git a/engines/sci/engine/script_patches.cpp b/engines/sci/engine/script_patches.cpp
index 97e53a0742..82a10d5e31 100644
--- a/engines/sci/engine/script_patches.cpp
+++ b/engines/sci/engine/script_patches.cpp
@@ -704,8 +704,8 @@ static const SciScriptPatcherEntry freddypharkasSignatures[] = {
 // Several scripts in Hoyle5 contain a subroutine which spins on kGetTime until
 // a certain number of ticks elapse. Since this wastes CPU and makes ScummVM
 // unresponsive, the kWait kernel function (which was removed in SCI2) is
-// reintroduced at 0x4f in kernel.cpp only for Hoyle5, and the spin subroutines
-// are patched here to call that function instead.
+// reintroduced for Hoyle5, and the spin subroutines are patched here to call
+// that function instead.
 // Applies to at least: English Demo
 static const uint16 hoyle5SignatureSpinLoop[] = {
 	SIG_MAGICDWORD,
@@ -719,10 +719,10 @@ static const uint16 hoyle5SignatureSpinLoop[] = {
 };
 
 static const uint16 hoyle5PatchSpinLoop[] = {
-	0x78,                           // push1
-	0x8f, 0x01,                     // lsp param[1]
-	0x43, 0x4f, PATCH_UINT16(0x02), // callk Wait, $2
-	0x48,                           // ret
+	0x78,                                     // push1
+	0x8f, 0x01,                               // lsp param[1]
+	0x43, kScummVMWaitId, PATCH_UINT16(0x02), // callk Wait, $2
+	0x48,                                     // ret
 	PATCH_END
 };