use arithmetic shift instead of signed div by 2

Source/DiabloUI/text_draw.cpp

@@ -10,7 +10,7 @@ DEVILUTION_BEGIN_NAMESPACE
 static int AlignXOffset(int flags, const SDL_Rect& dest, int w)
 {
 	if (flags & UIS_HCENTER)
-		return (dest.w - w) / 2;
+		return (dest.w - w) >> 1;
 	if (flags & UIS_RIGHT)
 		return dest.w - w;
 	return 0;
@@ -57,7 +57,7 @@ void DrawArtStr(const char* text, const SDL_Rect& rect, int flags)
 	}
 
 	int x = rect.x + AlignXOffset(flags, rect, w) + SCREEN_X;
-	int y = rect.y + ((flags & UIS_VCENTER) ? (rect.h - h) / 2 : 0) + SCREEN_Y + h;
+	int y = rect.y + ((flags & UIS_VCENTER) ? ((rect.h - h) >> 1) : 0) + SCREEN_Y + h;
 
 	y += dy;
 	h += dy;

Source/control.cpp

@@ -381,6 +381,7 @@ void DrawSkillIcons()
 	case TGT_OBJECT:
 		str = "Object";
 		numchar = lengthof("Object") - 1;
+		static_assert((lengthof("Object") - 1) * SMALL_FONT_HEIGHT <= 2 * SPLICON_WIDTH, "DrawSkillIcons uses unsigned division to calculate sy.");
 		break;
 	case TGT_OTHER:
 		str = "Other";
@@ -399,12 +400,12 @@ void DrawSkillIcons()
 	}
 	// PrintSmallVerticalStr centered
 	int sx = PANEL_X + PANEL_WIDTH - SMALL_FONT_HEIGHT - 2;
-	int sy = PANEL_Y + PANEL_HEIGHT - 2 * SPLICON_WIDTH + (2 * SPLICON_WIDTH - numchar * SMALL_FONT_HEIGHT) / 2;
+	int sy = PANEL_Y + PANEL_HEIGHT - 2 * SPLICON_WIDTH + (2 * SPLICON_WIDTH - numchar * SMALL_FONT_HEIGHT) / 2u;
 	for (unsigned i = 0; i < numchar; i++) {
 		sy += SMALL_FONT_HEIGHT;
 		BYTE nCel = gbStdFontFrame[str[i]];
 		// PrintSmallChar(sx + (SMALL_FONT_WIDTH - smallFontWidth[nCel]) / 2, sy, str[i], COL_GOLD);
-		PrintSmallColorChar(sx + (13 - smallFontWidth[nCel]) / 2, sy, nCel, COL_GOLD);
+		PrintSmallColorChar(sx + (13 - smallFontWidth[nCel]) / 2u, sy, nCel, COL_GOLD);
 	}
 }
 
@@ -1462,7 +1463,7 @@ static int DrawTooltip2(const char* text1, const char* text2, int x, int y, BYTE
 
 	if (y < 0)
 		return result;
-	x -= width / 2;
+	x -= width / 2u;
 	if (x < 0) {
 		result = -x;
 		x = 0;
@@ -1532,8 +1533,8 @@ static POS32 GetMousePos(int x, int y)
 		pos.y <<= 1;
 	}
 
-	pos.x += SCREEN_WIDTH / 2;
-	pos.y += VIEWPORT_HEIGHT / 2;
+	pos.x += SCREEN_WIDTH / 2u;
+	pos.y += VIEWPORT_HEIGHT / 2u;
 
 	return pos;
 }
@@ -1569,7 +1570,7 @@ static int DrawTooltip(const char* text, int x, int y, BYTE col)
 
 	if (y < 0)
 		return result;
-	x -= width / 2;
+	x -= width / 2u;
 	if (x < 0) {
 		result = -x;
 		x = 0;
@@ -1831,7 +1832,7 @@ void DrawInfoStr()
 		DrawTrigInfo();
 	} else if (pcursicon >= CURSOR_FIRSTITEM) {
 		GetItemInfo(&myplr._pHoldItem);
-		DrawTooltip(infostr, MousePos.x + cursW / 2, MousePos.y - TOOLTIP_OFFSET, infoclr);
+		DrawTooltip(infostr, MousePos.x + cursW / 2u, MousePos.y - TOOLTIP_OFFSET, infoclr);
 	}
 }
 

Source/controls/modifier_hints.cpp

@@ -32,11 +32,11 @@ struct CircleMenuHint {
 	    , bottom(bottom)
 	    , left(left)
 	{
-		int left_w = CalculateTextWidth(left);
-		int x_mid = left_w + SpaceWidth() * 5 / 2;
+		int left_w = CalculateTextWidth(left); // std::max(CalculateTextWidth(left), CalculateTextWidth(right));
+		int x_mid = left_w + SpaceWidth() * 5 / 2u;
 		width = 2 * x_mid;
-		top_offx = x_mid - CalculateTextWidth(top) / 2;
-		bottom_offx = x_mid - CalculateTextWidth(bottom) / 2;
+		top_offx = x_mid - CalculateTextWidth(top) / 2u;
+		bottom_offx = x_mid - CalculateTextWidth(bottom) / 2u;
 		right_offx = left_w + SpaceWidth() * 5;
 	}
 

Source/debug.cpp

@@ -251,6 +251,10 @@ void ValidateData()
 		if (gbStdFontFrame[i] >= lengthof(smallFontWidth))
 			app_fatal("Width of the small font %d ('%c') is undefined (frame number: %d).", i, i, gbStdFontFrame[i]);
 	}
+	for (i = 0; i < lengthof(smallFontWidth); i++) {
+		if (smallFontWidth[i] > 13)
+			app_fatal("Width of the small font %d is too high.", i); // required by DrawSkillIcons
+	}
 
 	if (GetHugeStringWidth("Pause") != 135)
 		app_fatal("gmenu_draw_pause expects hardcoded width 135.");

Source/diablo.cpp

@@ -141,7 +141,7 @@ static int diablo_parse_flags(int argc, char** argv)
 
 static void diablo_init_screen()
 {
-	MousePos.x = SCREEN_WIDTH / 2;
+	MousePos.x = SCREEN_WIDTH / 2u;
 	MousePos.y = MAINMENU_TOP + MAINMENU_ITEM_HEIGHT / 2;
 #if HAS_GAMECTRL || HAS_JOYSTICK || HAS_KBCTRL || HAS_DPAD
 	if (!sgbControllerActive)

Source/drlg_l4.cpp

@@ -1374,7 +1374,7 @@ static void L4RoomGen(int x, int y, int w, int h, bool dir)
 		for (i = 20; i != 0; i--) {
 			width = RandRange(2, 6) & ~1;
 			height = RandRange(2, 6) & ~1;
-			ry = h / 2 + y - height / 2;
+			ry = h / 2u + y - height / 2u;
 			rx = x - width;
 			if (L4CheckVHall(x, ry - 1, height + 2)
 			 && L4CheckRoom(rx - 1, ry - 1, width + 1, height + 2))  /// BUGFIX: swap args 3 and 4 ("ch+2" and "cw+1") (fixed)
@@ -1400,7 +1400,7 @@ static void L4RoomGen(int x, int y, int w, int h, bool dir)
 		for (i = 20; i != 0; i--) {
 			width = RandRange(2, 6) & ~1;
 			height = RandRange(2, 6) & ~1;
-			rx = w / 2 + x - width / 2;
+			rx = w / 2u + x - width / 2u;
 			ry = y - height;
 			if (L4CheckHHall(y, rx - 1, width + 2)
 			 && L4CheckRoom(rx - 1, ry - 1, width + 2, height + 1))
@@ -1959,29 +1959,29 @@ static void DRLG_L4ThemeExitFix()
 		y2 = themes[i]._tsy2;
 		switch (random_(0, 4)) {
 		case 0:
-			yy = (y1 + y2 + 1) / 2;
+			yy = (y1 + y2 + 1) / 2u;
 			dungeon[x1][yy - 1] = 53;
 			dungeon[x1][yy + 0] = 50;
 			dungeon[x1][yy + 1] = 52;
 			//dungeon[x2 - 1][yy - 1] = 54;
 			break;
 		case 1:
-			yy = (y1 + y2 + 1) / 2;
+			yy = (y1 + y2 + 1) / 2u;
 			dungeon[x2][yy - 1] = 53;
 			dungeon[x2][yy + 0] = 50;
 			dungeon[x2][yy + 1] = 52;
 			//dungeon[x2 - 1][yy - 1] = 54;
 			break;
 		case 2:
-			xx = (x1 + x2 + 1) / 2;
+			xx = (x1 + x2 + 1) / 2u;
 			dungeon[xx - 1][y1] = 57;
 			dungeon[xx + 0][y1] = 50;
 			dungeon[xx + 1][y1] = 56;
 			//dungeon[xx + 0][y2 - 1] = 59;
 			//dungeon[xx - 1][y2 - 1] = 58;
 			break;
 		case 3:
-			xx = (x1 + x2 + 1) / 2;
+			xx = (x1 + x2 + 1) / 2u;
 			dungeon[xx - 1][y2] = 57;
 			dungeon[xx + 0][y2] = 50;
 			dungeon[xx + 1][y2] = 56;

Source/gmenu.cpp

@@ -182,8 +182,8 @@ static TMenuItem* current_menu_item(bool activate)
 	if (!(pItem->dwFlags & GMF_ENABLED)) {
 		return NULL;
 	}
-	w = gmenu_get_lfont(pItem) / 2;
-	if (abs(MousePos.x - SCREEN_WIDTH / 2) > w)
+	w = gmenu_get_lfont(pItem) / 2u;
+	if (abs(MousePos.x - (int)(SCREEN_WIDTH / 2u)) > w)
 		return NULL;
 
 	if (activate)
@@ -285,7 +285,7 @@ static void gmenu_mouse_slider()
 	TMenuItem* pItem;
 	int offset;
 
-	offset = MousePos.x - (SCREEN_WIDTH / 2 - SLIDER_ROW_WIDTH / 2 + SLIDER_OFFSET + SLIDER_BORDER + SLIDER_BUTTON_WIDTH / 2);
+	offset = MousePos.x - (SCREEN_WIDTH / 2u - SLIDER_ROW_WIDTH / 2 + SLIDER_OFFSET + SLIDER_BORDER + SLIDER_BUTTON_WIDTH / 2);
 	if (offset < 0) {
 		if (offset < -(SLIDER_BUTTON_WIDTH / 2))
 			return;
@@ -351,8 +351,9 @@ void gmenu_slider_set(TMenuItem* pItem, int min, int max, int value)
 	int nSteps;
 
 	//assert(pItem != NULL);
+	//assert(max > min);
 	nSteps = pItem->wMenuParam1;
-	pItem->wMenuParam2 = ((max - min) / 2 + (value - min) * nSteps) / (max - min);
+	pItem->wMenuParam2 = ((max - min) / 2u + (value - min) * nSteps) / (max - min);
 }
 
 int gmenu_slider_get(TMenuItem* pItem, int min, int max)

Source/scrollrt.cpp

@@ -1253,14 +1253,14 @@ static void scrollrt_draw(int x, int y, int sx, int sy, int rows, int columns)
  */
 static void Zoom()
 {
-	int wdt = SCREEN_WIDTH / 2;
-	int nSrcOff = SCREENXY(SCREEN_WIDTH / 2 - 1, VIEWPORT_HEIGHT / 2 - 1);
+	int wdt = SCREEN_WIDTH / 2u;
+	int nSrcOff = SCREENXY(SCREEN_WIDTH / 2u - 1, VIEWPORT_HEIGHT / 2u - 1);
 	int nDstOff = SCREENXY(SCREEN_WIDTH - 1, VIEWPORT_HEIGHT - 1);
 
 	BYTE* src = &gpBuffer[nSrcOff];
 	BYTE* dst = &gpBuffer[nDstOff];
 
-	for (int hgt = 0; hgt < VIEWPORT_HEIGHT / 2; hgt++) {
+	for (unsigned hgt = 0; hgt < VIEWPORT_HEIGHT / 2u; hgt++) {
 		for (int i = 0; i < wdt; i++) {
 			*dst-- = *src;
 			*dst-- = *src;

Source/storm/storm_svid.cpp

@@ -420,8 +420,8 @@ bool SVidPlayContinue()
 		outputRect.w = SVidWidth * outputSurface->h / SVidHeight;
 		outputRect.h = outputSurface->h;
 	}
-	outputRect.x = (outputSurface->w - outputRect.w) / 2;
-	outputRect.y = (outputSurface->h - outputRect.h) / 2;
+	outputRect.x = (outputSurface->w - outputRect.w) >> 1;
+	outputRect.y = (outputSurface->h - outputRect.h) >> 1;
 
 	if (isIndexedOutputFormat
 	 || outputSurface->w == static_cast<int>(SVidWidth)

tools/patcher/DiabloUI/text_draw.cpp

@@ -10,7 +10,7 @@ DEVILUTION_BEGIN_NAMESPACE
 static int AlignXOffset(int flags, const SDL_Rect& dest, int w)
 {
 	if (flags & UIS_HCENTER)
-		return (dest.w - w) / 2;
+		return (dest.w - w) >> 1;
 	if (flags & UIS_RIGHT)
 		return dest.w - w;
 	return 0;
@@ -57,7 +57,7 @@ void DrawArtStr(const char* text, const SDL_Rect& rect, int flags)
 	}
 
 	int x = rect.x + AlignXOffset(flags, rect, w) + SCREEN_X;
-	int y = rect.y + ((flags & UIS_VCENTER) ? (rect.h - h) / 2 : 0) + SCREEN_Y + h;
+	int y = rect.y + ((flags & UIS_VCENTER) ? ((rect.h - h) >> 1) : 0) + SCREEN_Y + h;
 
 	y += dy;
 	h += dy;

tools/patcher/diablo.cpp

@@ -42,7 +42,7 @@ static int diablo_parse_flags(int argc, char** argv)
 
 static void diablo_init_screen()
 {
-	MousePos.x = SCREEN_WIDTH / 2;
+	MousePos.x = SCREEN_WIDTH / 2u;
 	MousePos.y = MAINMENU_TOP + MAINMENU_ITEM_HEIGHT / 2;
 #if HAS_GAMECTRL || HAS_JOYSTICK || HAS_KBCTRL || HAS_DPAD
 	if (!sgbControllerActive)