SCI: Replace magic '-42' by an enum

svn-id: r44492

3 files changed, 13 insertions, 8 deletions

diff --git a/engines/sci/console.cpp b/engines/sci/console.cpp
index 032264bcaf..1cba6077d2 100644
--- a/engines/sci/console.cpp
+++ b/engines/sci/console.cpp
@@ -2003,7 +2003,7 @@ bool Console::cmdBacktrace(int argc, const char **argv) {
 		break;
 
 		case EXEC_STACK_TYPE_KERNEL: // Kernel function
-			printf(" %x:[%x]  k%s(", i, call.origin, _vm->getKernel()->getKernelName(-(call.selector) - 42).c_str());
+			printf(" %x:[%x]  k%s(", i, call.origin, _vm->getKernel()->getKernelName(kMagicSelectorOffset - call.selector).c_str());
 			break;
 
 		case EXEC_STACK_TYPE_VARSELECTOR:
diff --git a/engines/sci/engine/vm.cpp b/engines/sci/engine/vm.cpp
index c9b665d881..acb89824b2 100644
--- a/engines/sci/engine/vm.cpp
+++ b/engines/sci/engine/vm.cpp
@@ -953,7 +953,7 @@ void run_vm(EngineState *s, int restoring) {
 						xstack = add_exec_stack_entry(s, NULL_REG, NULL, NULL_REG, argc, argv - 1, 0, NULL_REG,
 	                              s->_executionStack.size()-1, SCI_XS_CALLEE_LOCALS);
 						// Debugging hack to identify kernel function
-						xstack->selector = -42 - opparams[0];
+						xstack->selector = kMagicSelectorOffset - opparams[0];
 						xstack->type = EXEC_STACK_TYPE_KERNEL;
 
 						// Call kernel function
@@ -962,14 +962,11 @@ void run_vm(EngineState *s, int restoring) {
 						// Remove callk stack frame again
 						s->_executionStack.pop_back();
 					} else {
-						Common::String warningMsg = "Dummy function " + kfun.orig_name + "[";
-						warningMsg += warningMsg.printf("0x%x", opparams[0]);
-						warningMsg += "] invoked - ignoring. Params: ";
-						warningMsg += warningMsg.printf("%d", argc);
-						warningMsg += " (";
+						Common::String warningMsg = "Dummy function " + kfun.orig_name;
+						warningMsg += Common::String::printf("[0x%x] invoked - ignoring. Params: %d (", opparams[0], argc);
 
 						for (int i = 0; i < argc; i++) {
-							warningMsg += warningMsg.printf("%04x:%04x", PRINT_REG(argv[i]));
+							warningMsg +=  Common::String::printf("%04x:%04x", PRINT_REG(argv[i]));
 							warningMsg += (i == argc - 1 ? ")" : ", ");
 						}
 
diff --git a/engines/sci/engine/vm.h b/engines/sci/engine/vm.h
index 530a293081..9247bfa350 100644
--- a/engines/sci/engine/vm.h
+++ b/engines/sci/engine/vm.h
@@ -102,6 +102,14 @@ enum SelectorType {
 	kSelectorMethod
 };
 
+enum {
+	/**
+	 * Magic offset, used to compute fake selector values for use in ExecStack
+	 * when doing a callk. See the callk code in vm.cpp for details.
+	 */
+	kMagicSelectorOffset = -42
+};
+
 struct Class {
 	int script; /**< number of the script the class is in, -1 for non-existing */
 	reg_t reg; /**< offset; script-relative offset, segment: 0 if not instantiated */