Create a define for the special "signal" offset used throughout the engine, and fixed the arbitrary 0 values from commit #44294, set when some math functions do invalid calculations

svn-id: r44359

9 files changed, 33 insertions, 29 deletions

diff --git a/engines/sci/console.cpp b/engines/sci/console.cpp
index 2b3570daf5..e50139b3bc 100644
--- a/engines/sci/console.cpp
+++ b/engines/sci/console.cpp
@@ -2750,7 +2750,7 @@ bool Console::cmdStopSfx(int argc, const char **argv) {
 	if (id.segment) {
 		_vm->_gamestate->_sound.sfx_song_set_status(handle, SOUND_STATUS_STOPPED);
 		_vm->_gamestate->_sound.sfx_remove_song(handle);
-		PUT_SEL32V(id, signal, -1);
+		PUT_SEL32V(id, signal, SIGNAL_OFFSET);
 		PUT_SEL32V(id, nodePtr, 0);
 		PUT_SEL32V(id, handle, 0);
 	}
diff --git a/engines/sci/engine/kfile.cpp b/engines/sci/engine/kfile.cpp
index 2a1d997da4..df4e3274af 100644
--- a/engines/sci/engine/kfile.cpp
+++ b/engines/sci/engine/kfile.cpp
@@ -144,7 +144,7 @@ void file_open(EngineState *s, const char *filename, int mode) {
 
 	if (!inFile && !outFile) { // Failed
 		debug(3, "file_open() failed");
-		s->r_acc = make_reg(0, -1);
+		s->r_acc = make_reg(0, SIGNAL_OFFSET);
 		return;
 	}
 
diff --git a/engines/sci/engine/kgraphics.cpp b/engines/sci/engine/kgraphics.cpp
index 363ce81910..fc72e6e3f1 100644
--- a/engines/sci/engine/kgraphics.cpp
+++ b/engines/sci/engine/kgraphics.cpp
@@ -873,7 +873,7 @@ reg_t kIsItSkip(EngineState *s, int, int argc, reg_t *argv) {
 
 	if (!res) {
 		warning("[GFX] Attempt to get cel parameters for invalid view %d", view);
-		return make_reg(0, -1);
+		return make_reg(0, SIGNAL_OFFSET);
 	}
 
 	pxm = res->loops[loop].cels[cel];
diff --git a/engines/sci/engine/kmath.cpp b/engines/sci/engine/kmath.cpp
index 97f3ca4382..f2702839ca 100644
--- a/engines/sci/engine/kmath.cpp
+++ b/engines/sci/engine/kmath.cpp
@@ -129,8 +129,8 @@ reg_t kCosDiv(EngineState *s, int, int argc, reg_t *argv) {
 	double cosval = cos(angle * PI / 180.0);
 
 	if ((cosval < 0.0001) && (cosval > -0.0001)) {
-		warning("Attempted division by zero");
-		return make_reg(0, 0);
+		warning("kCosDiv: Attempted division by zero");
+		return make_reg(0, SIGNAL_OFFSET);
 	} else
 		return make_reg(0, (int16)(value / cosval));
 }
@@ -141,8 +141,8 @@ reg_t kSinDiv(EngineState *s, int, int argc, reg_t *argv) {
 	double sinval = sin(angle * PI / 180.0);
 
 	if ((sinval < 0.0001) && (sinval > -0.0001)) {
-		warning("Attempted division by zero");
-		return make_reg(0, 0);
+		warning("kSinDiv: Attempted division by zero");
+		return make_reg(0, SIGNAL_OFFSET);
 	} else
 		return make_reg(0, (int16)(value / sinval));
 }
@@ -153,8 +153,8 @@ reg_t kTimesTan(EngineState *s, int, int argc, reg_t *argv) {
 
 	param -= 90;
 	if ((param % 90) == 0) {
-		warning("Attempted tan(pi/2)");
-		return make_reg(0, 0);
+		warning("kTimesTan: Attempted tan(pi/2)");
+		return make_reg(0, SIGNAL_OFFSET);
 	} else
 		return make_reg(0, (int16) - (tan(param * PI / 180.0) * scale));
 }
@@ -164,8 +164,8 @@ reg_t kTimesCot(EngineState *s, int, int argc, reg_t *argv) {
 	int scale = (argc > 1) ? argv[1].toSint16() : 1;
 
 	if ((param % 90) == 0) {
-		warning("Attempted tan(pi/2)");
-		return make_reg(0, 0);
+		warning("kTimesCot: Attempted tan(pi/2)");
+		return make_reg(0, SIGNAL_OFFSET);
 	} else
 		return make_reg(0, (int16)(tan(param * PI / 180.0) * scale));
 }
diff --git a/engines/sci/engine/kmisc.cpp b/engines/sci/engine/kmisc.cpp
index 1ec2ffee1c..dbbb10a4d1 100644
--- a/engines/sci/engine/kmisc.cpp
+++ b/engines/sci/engine/kmisc.cpp
@@ -60,7 +60,7 @@ reg_t kGameIsRestarting(EngineState *s, int, int argc, reg_t *argv) {
 }
 
 reg_t kHaveMouse(EngineState *s, int, int argc, reg_t *argv) {
-	return make_reg(0, -1);
+	return make_reg(0, SIGNAL_OFFSET);
 }
 
 enum kMemoryInfoFunc {
diff --git a/engines/sci/engine/kmovement.cpp b/engines/sci/engine/kmovement.cpp
index a647a84cdb..ac4a2382ad 100644
--- a/engines/sci/engine/kmovement.cpp
+++ b/engines/sci/engine/kmovement.cpp
@@ -401,7 +401,7 @@ reg_t kDoAvoider(EngineState *s, int, int argc, reg_t *argv) {
 	int dx, dy;
 	int destx, desty;
 
-	s->r_acc = make_reg(0, -1);
+	s->r_acc = make_reg(0, SIGNAL_OFFSET);
 
 	if (!s->segMan->isHeapObject(avoider)) {
 		warning("DoAvoider() where avoider %04x:%04x is not an object", PRINT_REG(avoider));
diff --git a/engines/sci/engine/ksound.cpp b/engines/sci/engine/ksound.cpp
index 43dfcae98b..628b8313b1 100644
--- a/engines/sci/engine/ksound.cpp
+++ b/engines/sci/engine/ksound.cpp
@@ -184,7 +184,7 @@ void process_sound_events(EngineState *s) { /* Get all sound events, apply their
 			debugC(2, kDebugLevelSound, "[process-sound] Song %04x:%04x looped (to %d)\n",
 			          PRINT_REG(obj), cue);
 			/*			PUT_SEL32V(obj, loops, GET_SEL32V(obj, loop) - 1);*/
-			PUT_SEL32V(obj, signal, -1);
+			PUT_SEL32V(obj, signal, SIGNAL_OFFSET);
 			break;
 
 		case SI_RELATIVE_CUE:
@@ -202,7 +202,7 @@ void process_sound_events(EngineState *s) { /* Get all sound events, apply their
 		case SI_FINISHED:
 			debugC(2, kDebugLevelSound, "[process-sound] Song %04x:%04x finished\n",
 			          PRINT_REG(obj));
-			PUT_SEL32V(obj, signal, -1);
+			PUT_SEL32V(obj, signal, SIGNAL_OFFSET);
 			PUT_SEL32V(obj, state, _K_SOUND_STATUS_STOPPED);
 			break;
 
@@ -372,7 +372,7 @@ static reg_t kDoSoundSci0(EngineState *s, int argc, reg_t *argv) {
 		if (obj.segment) {
 			s->_sound.sfx_song_set_status(handle, SOUND_STATUS_STOPPED);
 			PUT_SEL32V(obj, state, SOUND_STATUS_STOPPED);
-			PUT_SEL32V(obj, signal, -1);
+			PUT_SEL32V(obj, signal, SIGNAL_OFFSET);
 		}
 		break;
 
@@ -560,7 +560,7 @@ static reg_t kDoSoundSci1Early(EngineState *s, int argc, reg_t *argv) {
 		break;
 	}
 	case _K_SCI01_SOUND_STOP_HANDLE : {
-		PUT_SEL32V(obj, signal, -1);
+		PUT_SEL32V(obj, signal, SIGNAL_OFFSET);
 		if (obj.segment) {
 			s->_sound.sfx_song_set_status(handle, SOUND_STATUS_STOPPED);
 		}
@@ -581,7 +581,7 @@ static reg_t kDoSoundSci1Early(EngineState *s, int argc, reg_t *argv) {
 		 * TODO: Figure out the exact semantics */
 
 		/* FIXME: The next couple of lines actually STOP the song right away */
-		PUT_SEL32V(obj, signal, -1);
+		PUT_SEL32V(obj, signal, SIGNAL_OFFSET);
 		if (obj.segment) {
 			s->_sound.sfx_song_set_status(handle, SOUND_STATUS_STOPPED);
 		}
@@ -622,7 +622,7 @@ static reg_t kDoSoundSci1Early(EngineState *s, int argc, reg_t *argv) {
 
 		case SI_FINISHED:
 			debugC(2, kDebugLevelSound, "---    [FINISHED] %04x:%04x\n", PRINT_REG(obj));
-			PUT_SEL32V(obj, signal, -1);
+			PUT_SEL32V(obj, signal, SIGNAL_OFFSET);
 			break;
 
 		case SI_LOOP:
@@ -842,7 +842,7 @@ static reg_t kDoSoundSci1Late(EngineState *s, int argc, reg_t *argv) {
 					warning("Could not open song number %d", number);
 					// Send a "stop handle" event so that the engine won't wait forever here
 					s->_sound.sfx_song_set_status(handle, SOUND_STATUS_STOPPED);
-					PUT_SEL32V(obj, signal, -1);
+					PUT_SEL32V(obj, signal, SIGNAL_OFFSET);
 					return s->r_acc;
 				}
 				debugC(2, kDebugLevelSound, "Initializing song number %d\n", number);
@@ -890,7 +890,7 @@ static reg_t kDoSoundSci1Late(EngineState *s, int argc, reg_t *argv) {
 		break;
 	}
 	case _K_SCI1_SOUND_STOP_HANDLE : {
-		PUT_SEL32V(obj, signal, -1);
+		PUT_SEL32V(obj, signal, SIGNAL_OFFSET);
 		if (obj.segment) {
 			s->_sound.sfx_song_set_status(handle, SOUND_STATUS_STOPPED);
 		}
@@ -914,13 +914,13 @@ static reg_t kDoSoundSci1Late(EngineState *s, int argc, reg_t *argv) {
 			/* FIXME: The next couple of lines actually STOP the handle, rather
 			** than fading it! */
 			if (argv[5].toUint16()) {
-				PUT_SEL32V(obj, signal, -1);
+				PUT_SEL32V(obj, signal, SIGNAL_OFFSET);
 				PUT_SEL32V(obj, nodePtr, 0);
 				PUT_SEL32V(obj, handle, 0);
 				s->_sound.sfx_song_set_status(handle, SOUND_STATUS_STOPPED);
 			} else {
 				// FIXME: Support fade-and-continue. For now, send signal right away.
-				PUT_SEL32V(obj, signal, -1);
+				PUT_SEL32V(obj, signal, SIGNAL_OFFSET);
 			}
 		}
 		break;
@@ -976,7 +976,7 @@ static reg_t kDoSoundSci1Late(EngineState *s, int argc, reg_t *argv) {
 			break;
 
 		case SI_FINISHED:
-			PUT_SEL32V(obj, signal, -1);
+			PUT_SEL32V(obj, signal, SIGNAL_OFFSET);
 			break;
 
 		case SI_LOOP:
@@ -1106,7 +1106,7 @@ reg_t kDoSync(EngineState *s, int, int argc, reg_t *argv) {
 		} else {
 			warning("DoSync: failed to find resource %s", id.toString().c_str());
 			// Notify the scripts to stop sound sync
-			PUT_SEL32V(argv[1], syncCue, -1);
+			PUT_SEL32V(argv[1], syncCue, SIGNAL_OFFSET);
 		}
 		break;
 	}
diff --git a/engines/sci/engine/vm_types.h b/engines/sci/engine/vm_types.h
index ba8a4d7057..62dc35aae7 100644
--- a/engines/sci/engine/vm_types.h
+++ b/engines/sci/engine/vm_types.h
@@ -67,9 +67,13 @@ typedef reg_t *StackPtr;
 typedef int Selector;
 #define NULL_SELECTOR -1
 
+// Offset sent to indicate an error, or that an operation has finished
+// (depending on the case)
+#define SIGNAL_OFFSET 0xffff
+
 #define PRINT_STK(v) (unsigned) (v - s->stack_base)
 
-static inline reg_t make_reg(SegmentId segment, int16 offset) {
+static inline reg_t make_reg(SegmentId segment, uint16 offset) {
 	reg_t r;
 	r.offset = offset;
 	r.segment = segment;
diff --git a/engines/sci/gfx/menubar.cpp b/engines/sci/gfx/menubar.cpp
index d6debea824..1c04486d4d 100644
--- a/engines/sci/gfx/menubar.cpp
+++ b/engines/sci/gfx/menubar.cpp
@@ -343,10 +343,10 @@ int Menubar::setAttribute(EngineState *s, int menu_nr, int item_nr, int attribut
 
 reg_t Menubar::getAttribute(int menu_nr, int item_nr, int attribute) const {
 	if ((menu_nr < 0) || (item_nr < 0))
-		return make_reg(0, -1);
+		return make_reg(0, SIGNAL_OFFSET);
 
 	if ((menu_nr >= (int)_menus.size()) || (item_nr >= (int)_menus[menu_nr]._items.size()))
-		return make_reg(0, -1);
+		return make_reg(0, SIGNAL_OFFSET);
 
 	const MenuItem &item = _menus[menu_nr]._items[item_nr];
 
@@ -368,7 +368,7 @@ reg_t Menubar::getAttribute(int menu_nr, int item_nr, int attribute) const {
 
 	default:
 		warning("Attempt to read invalid attribute from menu %d, item %d: 0x%04x", menu_nr, item_nr, attribute);
-		return make_reg(0, -1);
+		return make_reg(0, SIGNAL_OFFSET);
 	}
 }